The investigators examined whether supplying coniferyl alcohol, a compound positioned upstream of the lignan branch in the phenylpropanoid pathway, could support justicidin B production. The pathway described in the study proceeds through pinoresinol, lariciresinol and secoisolariciresinol before reaching downstream arylnaphthalene lignans including justicidin B.

The study used previously established root cultures derived from aseptically germinated seedlings. L. austriacum cultures were maintained on modified Murashige and Skoog medium supplemented with 1 mg/L α-naphthaleneacetic acid and 0.4 mg/L indole-3-acetic acid. L. alpinum cultures were maintained on modified Murashige and Skoog medium containing 5 mg/L indole-3-acetic acid, 2 mg/L kinetin and 1 g/L casein hydrolysate. Root cultures were subcultured every 30 days under controlled conditions before the experiments.

Justicidin B was measured by liquid chromatography coupled with high-resolution electrospray ionization mass spectrometry. The researchers characterized accumulation over a 30-day cultivation period before testing supplementation. In L. alpinum, justicidin B rose gradually from 0.07 μg/mg dry weight on day 5 to 0.08 on day 10 and 0.09 on day 20, remained at 0.09 on day 25 and reached 0.12 μg/mg dry weight on day 30.

L. austriacum showed a different profile. Its justicidin B content was 1.19 μg/mg dry weight on day 5, declined to 0.91 on day 10 and 0.75 on day 20, and reached 0.58 on day 25. It then partially recovered to 0.72 μg/mg dry weight on day 30. Untreated cultures and cultures treated with the ethanol vehicle served as controls, and all supplementation treatments were performed in triplicate.

In the five-day screening experiment, both species received coniferyl alcohol on cultivation day 25 at final concentrations of 10, 50 or 100 μM and were harvested on day 30. The ethanol controls did not differ significantly from untreated cultures in either species, with p = 0.924 for L. alpinum and p = 0.729 for L. austriacum. In L. alpinum, 10 μM yielded 0.09 μg/mg dry weight of justicidin B and 50 μM yielded 0.12, close to the untreated value of 0.12. The highest tested concentration, 100 μM, produced 0.14 μg/mg dry weight, about 1.2 times the untreated control.

The response in L. austriacum was larger. Supplementation with 10 μM increased justicidin B to 1.23 μg/mg dry weight, about 1.6 times the untreated control of 0.72, with p = 0.01. The strongest result followed 50 μM treatment: 1.49 μg/mg dry weight, approximately twice the untreated level, with p = 0.002. This treated value also exceeded the highest justicidin B level recorded during the 30-day untreated accumulation profile. At 100 μM, however, justicidin B measured 0.62 μg/mg dry weight, showing that the highest tested dose did not support accumulation.

Based on that screening result, the researchers selected 50 μM for further testing in L. austriacum. When the compound was added on cultivation day 30 and cultures were harvested on day 35, justicidin B reached 0.88 μg/mg dry weight, about 1.4 times the untreated value of 0.62. In cultures supplemented on day 35 and harvested on day 40, the treated value was 1.15 μg/mg dry weight, matching the untreated control of 1.15. These results associate the effectiveness of supplementation in this species with precursor concentration and cultivation stage, rather than indicating that additional coniferyl alcohol invariably raises metabolite output.

Overall, the experiments identify 50 μM coniferyl alcohol as the most effective tested condition for increasing justicidin B accumulation in L. austriacum root cultures, particularly when applied during the day-25-to-day-30 cultivation period. The findings support a role for precursor availability in justicidin B accumulation, but the results are bounded to the tested culture systems, doses, treatment schedules and two Linum species. The study assessed cultured roots rather than intact plants or large-scale production, and it did not establish clinical effects. It also did not determine which enzymatic steps or physiological factors caused the differences among concentrations and treatment times.

Subject of Research: Effects of coniferyl alcohol supplementation on justicidin B accumulation in Linum root cultures

Article Title: Coniferyl alcohol drives arylnaphthalene-type lignan biosynthesis in root cultures of Linum species

Article References: Zarev, Y., Nedelcheva, R., & Ionkova, I. (2026). Coniferyl alcohol drives arylnaphthalene-type lignan biosynthesis in root cultures of Linum species. Pharmacia, 73, Article e206407. https://doi.org/10.3897/pharmacia.73.e206407

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e206407

Keywords: coniferyl alcohol, justicidin B, Linum austriacum, Linum alpinum, root cultures, precursor feeding, lignan biosynthesis, plant biotechnology, in vitro cultures, Coniferyl, alcohol, drives

The results establish a communication system under controlled laboratory conditions, not yet a field-ready method for regulating microbes in agricultural soils. The researchers first installed the genetic code expansion machinery in B. subtilis PY79, a laboratory model strain. They used an engineered Methanocaldococcus jannaschii tyrosyl-tRNA synthetase and its corresponding suppressor tRNA, together with a fluorescent reporter containing an in-frame amber stop codon.

Without OMY, translation was expected to stop at that codon; with OMY, the reporter should be completed and become fluorescent. Exogenous OMY produced dose-dependent activation, including twofold induction at 1 micromolar and fivefold induction at 10 micromolar, although incomplete termination created substantial background signal. Adding a second amber codon reduced background almost 55-fold and yielded a 3,100-fold difference between conditions with and without OMY.

The number and position of stop codons therefore emerged as an important design variable rather than a universal setting. The system was not limited to a fluorescent marker. The researchers inserted an amber codon into the sfp gene, which encodes the enzyme required to activate the surfactin synthetase machinery.

Without OMY, the engineered B. subtilis strain produced no detectable surfactin; with 500 micromolar OMY, it produced approximately 0.18 grams per litre. OMY itself did not alter bacterial growth under the tested conditions. These experiments demonstrate that a plant-derived chemical can control bacterial protein production and a microbially synthesized compound.

They do not yet show that the platform can improve crop yield, control plant pathogens or safely deploy engineered organisms in an open agricultural environment. The result also remained dependent on the engineered translation machinery and the placement of amber codons in the targeted bacterial genes. On the plant side, the researchers engineered expression of the enzyme MfnG, which enables OMY biosynthesis.

Transient expression in Nicotiana benthamiana leaves produced a metabolite with the expected mass-to-charge ratio that coeluted with an OMY standard; no corresponding signal appeared in control leaves. They then generated stable Arabidopsis lines expressing an sfGFP–MfnG fusion under the constitutive UBQ10 promoter. Hydroponically grown transgenic seedlings released an average of 3.1 micromolar OMY into the surrounding medium, whereas none was detected from wild-type plants.

No optimization of metabolic flux, transport or tyrosine supplementation was required to reach this concentration in the laboratory setup. The finding establishes that a plant can manufacture and release the chemical signal under the tested growth conditions, without demonstrating how much would be available in a mature crop or a field rhizosphere. When the OMY-producing Arabidopsis plants were placed on agar with bacteria carrying an OMY-dependent NanoLuc reporter, luminescence appeared specifically around the transgenic roots.

In mixed plates containing transformed and wild-type seedlings, the signal remained concentrated around the OMY-producing plants, demonstrating genotype-specific activation rather than a general effect of seedling placement. OMY-independent bacteria also generated somewhat stronger signals near roots, which the researchers attributed to higher local bacterial density. The results nevertheless support spatial selectivity: chemical production by one plant could regulate nearby bacterial gene expression while producing a smaller signal around neighboring wild-type plants.

The researchers did not directly measure OMY concentration or bacterial cell density at the roots, so the relative contributions of the chemical gradient and local accumulation of cells remain unresolved. Constitutive OMY production carried a biological cost. Arabidopsis lines overexpressing MfnG had shorter primary roots, reduced lateral-root density, impaired gravitropism, delayed germination and a more rapid decline in seed viability with age.

Lateral-root density was the number of emerged lateral roots normalized by total primary-root length, rather than a direct count of lateral roots. Exogenous OMY inhibited wild-type root growth in a concentration-dependent manner, with a half-maximal inhibitory concentration of approximately 94–101 micromolar. The investigators found no evidence that the effect resulted from depletion of aromatic amino acid precursors or elevated misincorporation of OMY into native proteins.

Aromatic amino acid supplementation did not rescue the phenotype, and proteomics detected no significant increase in O-methylated tyrosine residues. The mechanism of toxicity therefore remained unresolved, although the severity of the measured effects was reduced when OMY production was restricted in space or time. The team next restricted when and where the signal was made.

A root-cap-specific promoter produced OMY in approximately one-fifth of root cells, while an estradiol-inducible system allowed production to be triggered by treatment. Both conditional designs produced less severe growth abnormalities than constitutive expression and brought root growth, lateral-root density, gravitropism and germination close to wild-type values. Root-cap-specific plants released 0.73 micromolar OMY in the tested hydroponic medium and activated the bacterial reporter in cocultivation, although their signal was weaker than that from constitutively expressing plants.

More sensitive flow-cytometry measurements detected reporter induction at OMY concentrations as low as 0.05 and 0.5 micromolar. The experiments therefore showed that spatially restricted production could preserve a detectable response without requiring the larger accumulation measured under constitutive expression. The inducible Arabidopsis system also produced a strong response after activation.

Plants treated with 20 micromolar estradiol generated approximately 18.7 times more maximum bacterial luminescence than uninduced plants. The peak-to-baseline ratio did not differ significantly between treated and untreated groups because the baseline did not decay equally between plant positions, showing why maximum intensity and spatial contrast must be interpreted separately. Collectively, the conditional experiments demonstrate a way to reduce the plant fitness costs while retaining measurable bacterial control.

They do not establish that either promoter would provide useful control in mature crops exposed to natural environmental and microbial variation. In particular, the estradiol system depends on an external chemical trigger, while the root-cap promoter is linked to a specific tissue and developmental context. To move beyond the model laboratory strain, the researchers engineered B. subtilis UD1022, a wild isolate known to colonize Arabidopsis roots.

Its response to OMY was dose-dependent, but its optimal reporter configuration differed from that of PY79: a single amber codon produced the best fold change in UD1022, whereas two codons were most effective in PY79. In autoclaved soil supplied with 500 micromolar OMY, UD1022 reporter fluorescence increased 41-fold by day three. When OMY-producing and wild-type Arabidopsis grew in the same sterilized soil, bacteria exposed to the engineered plants had a median fluorescence of 802 arbitrary fluorescence units, compared with 530 for wild-type plants, and the fluorescent bacterial fraction rose from 9.8% to 36.1%.

This experiment showed transfer of plant-derived OMY in soil, but its sterilized, single-strain setting excluded interactions with a natural microbial community. The platform was also tested in agriculturally relevant plants through a rapid hairy-root transformation method. Composite tomato plants carrying MfnG in transgenic hairy roots and composite poplar plants with the same construct produced luminescence from OMY-dependent B. subtilis reporters specifically at fluorescent-marker-positive roots.

These results show that OMY biosynthesis and bacterial activation can extend beyond Arabidopsis to tomato and poplar, but the shoots in the composite plants remained wild type, and the work did not produce stable, whole-plant transgenic crops. Field use will require testing in nonsterile soils, where OMY may be degraded or transformed by resident organisms, engineered bacteria may face competition, and unintended activation of native organisms must be assessed. The study’s central achievement is therefore a cross-kingdom proof of concept: plants can synthesize a chemical signal that selectively activates engineered bacterial genes, while tissue-specific and inducible production can limit the plant-level costs.

Subject of Research: Genetic code expansion for plant-directed control of engineered soil bacteria

Article Title: Genetic code expansion enables plant-directed control of bacterial activity

Article References: Zhong, V., Jones, M. A., Cabales, A., Gevorgyan, A., Inckemann, R., Johnson, A. A., Karunadasa, S. S., Forti, A. M., Xu, S.-L., Kunjapur, A. M., & Brophy, J. A. N. (2026). Genetic code expansion enables plant-directed control of bacterial activity. Nature Biotechnology. https://doi.org/10.1038/s41587-026-03360-5

Image Credits: AI Generated

DOI: 10.1038/s41587-026-03360-5

Keywords: genetic code expansion, noncanonical amino acids, plant-microbe signaling, synthetic biology, Bacillus subtilis, Arabidopsis, plant biotechnology, soil bacteria, OMY, surfactin, Genetic, code

The work was designed to address low maturation efficiency, identified by the authors as a major limitation to the commercial application of somatic embryogenesis. Somatic embryogenesis is a biotechnology platform used for large-scale propagation and germplasm conservation. The investigators first evaluated the five nitrogen sources and then used an L18(3⁵) orthogonal experimental design to test combinations of them.

This approach allowed the researchers to assess several source combinations systematically while examining total embryo formation and cotyledonary embryo formation as separate outcomes. The results showed distinct optima among the three tested slash pine lines. Medium 14 was most conducive to total embryo formation in the S7-5 and S24-1 lines and to cotyledonary embryo formation in S7-2.

Medium 11 was optimal for total embryo formation in S7-2 and for cotyledonary embryo differentiation in S24-1, while Medium 13 was most favorable for cotyledonary embryo formation in S7-5. These line-specific results suggest that the most effective nitrogen balance can differ according to the embryogenic material and the developmental stage being evaluated. The study therefore identified several practical media options rather than a single formulation intended to maximize every outcome across slash pine lines.

Its scope remained the controlled maturation of somatic embryos from the tested cultures. Correlation analysis identified calcium nitrate and glutamine as significant promoting factors associated with embryo maturation. Instead, calcium nitrate and glutamine emerged as components that tracked with improved maturation outcomes in the tested conditions.

Enzyme activity assays provided a biochemical measure accompanying the developmental response. Under the optimized nitrogen ratio, activity of glutamine synthetase, or GS, increased, while the activities of nitrate reductase, NR, and nitrite reductase, NiR, decreased. The authors interpreted this pattern as facilitating the assimilation of nitrogen into organic forms.

By linking medium composition to embryo formation, cotyledonary development and enzyme activity, the study provides a nitrogen-focused regulatory framework for slash pine somatic embryogenesis. The authors say the results offer theoretical foundations and technical support for large-scale breeding and genetic improvement. However, the reported evidence comes from laboratory maturation experiments with three slash pine lines; it does not establish performance across additional lines, laboratories, culture cycles or subsequent plant-regeneration stages.

Subject of Research: Nitrogen-source optimization for somatic embryo maturation in three Pinus elliottii embryogenic lines

Article Title: Optimization of nitrogen source ratios for somatic embryo maturation in Pinus elliottii

Article References: Xu, L., Liu, Q., Du, Q., Deng, Z., Ding, W., Luan, Q., & Yang, C. (2026). Optimization of nitrogen source ratios for somatic embryo maturation in Pinus elliottii. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09765-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09765-3

Keywords: slash pine, Pinus elliottii, somatic embryogenesis, nitrogen nutrition, embryo maturation, cotyledonary embryos, glutamine synthetase, nitrate reductase, plant biotechnology, orthogonal design, Optimization, nitrogen

The genes in question encode proteins from the BRI1 EMS SUPPRESSOR 1/BRASSINAZOLE RESISTANT 1 family, usually abbreviated BES1/BZR1. These transcription factors sit at the very end of the brassinosteroid signaling pathway, the cascade that carries instructions from steroid hormones at the cell surface down to the DNA in the nucleus. When brassinosteroids are abundant, BES1 and BZR1 proteins accumulate in the nucleus and switch large sets of genes on or off, promoting stem elongation, leaf expansion, flowering, and other growth processes. When the hormone signal is absent or when stress conditions demand a change of priorities, the proteins are phosphorylated and retained in the cytoplasm, effectively putting growth on hold. Because of this dual role, BES1/BZR1 factors have become a major focus for researchers trying to breed crops that grow vigorously while still tolerating hostile environments.

Despite their importance in the model plant Arabidopsis thaliana and in major cereals, the BES1/BZR1 family had not been systematically cataloged in flowering Chinese cabbage. A team led by Haobo Yang, Jinpeng Lu, Jia Li, and Hongyong Shi of Guangzhou University set out to close that gap. Using the recently available genome annotation of the crop, they searched the entire genome for sequences encoding the characteristic BES1-type DNA-binding motif, the molecular signature that allows these proteins to recognize their target genes. The search returned ten genes, which the team named BraBES1, each carrying the conserved motif that defines the family. That number fits the general pattern seen across the Brassica genus, whose genomes expanded through an ancient whole-genome triplication event that left many gene families larger than their counterparts in Arabidopsis.

Identifying the genes was only the first step. To understand how the ten BraBES1 proteins relate to one another and to their relatives in other species, the researchers carried out phylogenetic analysis, constructing an evolutionary tree of BES1/BZR1 proteins. The analysis sorted the wider family into six groups, designated A through F. The ten BraBES1 proteins from flowering Chinese cabbage fell into five of those groups, namely A, C, D, E, and F, with no member assigned to group B. This distribution matters because group membership often predicts function: proteins that cluster together tend to share DNA-binding preferences, interaction partners, and expression patterns inherited from a common ancestor. The absence of a group B representative suggests that whatever ancestral gene gave rise to that lineage was lost or diverged beyond recognition in this species.

The team also examined where the genes sit on the chromosomes and how their neighborhoods compare with those of Arabidopsis. The ten BraBES1 genes were distributed across seven chromosomes, and synteny analysis revealed strong conservation of genomic context with the BES1/BZR1 homologs of Arabidopsis. Synteny, the preservation of gene order across chromosomes of different species, is a powerful clue to evolutionary history. It indicates that the BraBES1 family members are true orthologs, descended from the same ancestral genes as their Arabidopsis counterparts rather than arising through unrelated duplications. For breeders and molecular biologists, this conserved synteny is practical good news, because it means that decades of functional knowledge accumulated in Arabidopsis can serve as a reasonable starting hypothesis for interpreting how the Brassica genes behave.

Subcellular localization provided the next layer of insight. Transcription factors must enter the nucleus to do their work, so where a protein accumulates within the cell often hints at how it is regulated. Using transient expression in tobacco leaves, the researchers found that BraBES1 proteins from groups A, E, and F localized to both the nucleus and the cytoplasm, while proteins from groups C and D were found predominantly in the nucleus. The cytoplasmic fraction in the first group is consistent with the canonical brassinosteroid logic, in which the GSK3-like kinase BIN2 phosphorylates BES1 and BZR1 in the absence of hormone, holding them outside the nucleus until brassinosteroid signaling releases them. The predominantly nuclear behavior of the C and D groups hints at a different regulatory logic, one that may not depend so heavily on hormone-controlled shuttling.

That interpretation gained support from protein interaction assays. Using yeast two-hybrid tests, which detect physical binding between two proteins inside yeast cells, the team showed that all ten BraBES1 proteins interact with BraSK21, a SHAGGY-LIKE KINASE 21 in the crop. In Arabidopsis, the equivalent kinase family, which includes BIN2, acts as the central brake on brassinosteroid signaling, phosphorylating BES1 and BZR1 to inactivate them. The finding that every BraBES1 member binds BraSK21 points to a conserved BR-associated regulatory module: a kinase-and-transcription-factor circuit that has been maintained across hundreds of millions of years of evolution and across the divergence of the Brassica and Arabidopsis lineages. Conservation at this level underscores how fundamental the pathway is to plant life, and it gives researchers an immediate entry point for manipulating the pathway in the vegetable.

Where the family truly diverges is in its regulatory wiring. The researchers found sequence variation among the ten genes, and their promoter regions, the stretches of DNA upstream of each gene that control when and where it is switched on, carried divergent cis-elements, the short motifs that bind other regulatory proteins. Consistent with that promoter diversity, the genes showed distinct expression profiles across tissues and conditions. When the team exposed plants to a panel of hormones, including brassinolide, the active brassinosteroid, along with gibberellic acid, the auxin indole-3-acetic acid, abscisic acid, and salicylic acid, each BraBES1 gene responded in its own characteristic pattern. The same held true under abiotic stresses: cold and heat, drought, high light, and salt each elicited gene-specific changes in expression. This is the signature of a gene family that has undergone subfunctionalization, in which duplicated copies shed redundant roles and each specialized for particular signals, tissues, or conditions.

One pattern stood out from the stress and hormone experiments. Genes in group A showed especially strong responsiveness to hormones and to high temperature in the cultivar Sijiu-19, a traditional variety of flowering Chinese cabbage. Given that heat stress is an increasingly serious constraint on vegetable production in southern China, a transcription factor family member that couples brassinosteroid signaling with heat responsiveness is an obvious candidate for further study. If group A BraBES1 genes turn out to mediate the well-documented role of brassinosteroids in thermotolerance, they could become targets for marker-assisted selection or genome editing aimed at producing varieties that hold their yield through heat waves. The authors position the whole dataset as a resource for exactly this kind of functional analysis of BR-linked development and stress adaptation.

The study is a reminder of how much modern crop improvement depends on cataloging the parts list before tinkering with the machine. By combining genome-wide identification, evolutionary classification, chromosomal synteny, protein localization, interaction mapping, and expression profiling under a dozen different treatments, the Guangzhou University team has built a multi-layered picture of a single transcription factor family in a crop that had been largely invisible to this kind of analysis. The conserved features, the shared DNA-binding motif, the interaction with BraSK21, the syntenic anchors to Arabidopsis, give the field confidence that established brassinosteroid biology transfers to flowering Chinese cabbage. The divergent features, the split localization patterns, the varied promoters, and the gene-specific responses to hormones and stresses, show where the interesting specialization lies. The next step, functional validation of individual BraBES1 genes in the crop itself, will determine whether this catalog becomes a toolkit for breeding leafy vegetables that grow fast, flower on schedule, and shrug off the stresses of a warming climate.

Subject of Research: BES1/BZR1 transcription factor gene family identification and brassinosteroid signaling in flowering Chinese cabbage

Article Title: Genome-wide identification of BraBES1 genes reveals conserved BR-module features and differential hormone/stress responsiveness in Brassica rapa var. parachinensis

Article References: Yang, H., Lu, J., Li, J., & Shi, H. (2026). Genome-wide identification of BraBES1 genes reveals conserved BR-module features and differential hormone/stress responsiveness in Brassica rapa var. parachinensis. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10215-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10215-3

Keywords: Brassica rapa, flowering Chinese cabbage, BES1/BZR1, brassinosteroid, transcription factors, gene family, phylogenetics, synteny, abiotic stress, hormone signaling, plant biotechnology, Guangzhou University

The two species at the center of the work, Linum austriacum and Linum alpinum, are recognized as some of the richest natural sources of arylnaphthalene lignans. L. austriacum is among the most productive justicidin B-accumulating species known, while L. alpinum, a rare alpine endemic of European mountain regions, has recently emerged as an additional promising source of the same bioactive lignan. Because harvesting wild plants is constrained by the limited range of these species and the low natural abundance of justicidin B, the research team turned to in vitro root cultures, which combine genetic and biochemical stability with rapid growth and the capacity to maintain specialized metabolic pathways under fully controlled conditions. Root cultures are established from aseptically germinated seedlings and maintained on modified Murashige and Skoog medium supplemented with defined auxins and, in the case of L. alpinum, kinetin and casein hydrolysate, subcultured every 30 days to keep biomass development and metabolic state uniform before each experiment.

Understanding why vitexin was chosen requires a look at the architecture of the phenylpropanoid pathway itself. This central metabolic network originates from phenylalanine and proceeds through cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, and coniferyl alcohol before the sequential formation of pinoresinol, lariciresinol, and secoisolariciresinol, ultimately yielding arylnaphthalene lignans including justicidin B. Crucially, the same pathway also gives rise to flavonoids and numerous other phenolic compounds, so the relative activity of competing branches plays a decisive role in determining which end products accumulate. Flavonoids have traditionally been regarded as terminal products of phenylpropanoid metabolism, but increasing evidence suggests they also participate in metabolic crosstalk and signaling within the network. Vitexin, a naturally occurring C-glycosyl flavone, is a characteristic specialized metabolite of Linum species: it and related mono- and di-C-glycosyl flavones have been identified in the aerial tissues of cultivated flax, and high-resolution mass spectrometry profiling of other Linum species has revealed vitexin among the major detected compounds. Prior work showing that stress-induced accumulation of phenolics, flavonoids including vitexin, and lignans occurs together in Linum cell cultures further supported the close metabolic relationship between the two branches.

Before any supplementation, the researchers first mapped the endogenous accumulation of justicidin B in untreated root cultures of both species over a 30-day cultivation period, quantifying the compound by liquid chromatography coupled with high-resolution electrospray ionization mass spectrometry using an external calibration curve prepared from purified justicidin B. The two species told strikingly different stories. In L. alpinum root cultures, justicidin B was consistently detected and rose gradually from 0.07 micrograms per milligram dry weight on day 5 to a maximum of 0.12 micrograms per milligram dry weight on day 30, with no early accumulation maximum, indicating a slow and progressive trend. In L. austriacum, justicidin B was already present at relatively high levels during early culture development, reaching 1.19 micrograms per milligram dry weight on day 5, then declined to 0.75 on day 20 and bottomed out at 0.58 on day 25, a dip the authors associate with increased biomass development, before partially recovering to 0.72 by day 30. This profile established that justicidin B accumulation in L. austriacum varies with culture age rather than progressing steadily, and it identified day 25 as a suitable intervention point, a phase of reduced endogenous production where the effect of an external supplement could be cleanly evaluated.

The first supplementation experiment applied vitexin at final concentrations of 1, 3, and 5 micromolar to root cultures of both species on cultivation day 25, with harvest after 5 days of treatment on day 30. Each treatment was performed in triplicate, and ethanol-treated cultures were included as solvent controls to distinguish the effects of vitexin from those of the solvent, since stock solutions were prepared in absolute ethanol and diluted with sterile distilled water immediately before use. The ethanol control proved statistically inert in every comparison, confirming that any changes in justicidin B content could be attributed to the flavonoid itself. The results were species-specific in a way that defied a simple concentration-response curve. In L. alpinum, 1 micromolar vitexin produced the highest justicidin B accumulation at 0.14 micrograms per milligram dry weight, roughly a 1.2-fold increase over the untreated control, while higher concentrations of 3 and 5 micromolar yielded contents comparable to controls, indicating that increasing the dose beyond 1 micromolar did not further enhance accumulation in this species.

L. austriacum responded far more dramatically. Supplementation with 1 micromolar vitexin increased justicidin B content to 0.93 micrograms per milligram dry weight, a tendency that fell just short of statistical significance, and 3 micromolar produced 0.86, but the strongest response came at 5 micromolar, where justicidin B reached 1.30 micrograms per milligram dry weight, an approximately 1.8-fold increase over the untreated control that was highly significant. Notably, 3 micromolar did not produce an intermediate response between 1 and 5 micromolar, so vitexin did not induce a simple dose-dependent pattern across the tested range. The authors interpret this as evidence that the effect depends on the metabolic capacity and physiological state of each root culture system, consistent with the known influence of genotype, culture conditions, and treatment optimization on secondary metabolite production in plant in vitro systems.

Because L. austriacum had shown the stronger response, the team extended the work with a prolonged supplementation experiment using higher concentrations and later cultivation stages. Independent sets of cultures were supplemented with 5 or 10 micromolar vitexin on day 30 and harvested on day 35, or supplemented on day 35 and harvested on day 40, again following 5 days of treatment. On day 35, 10 micromolar vitexin significantly increased justicidin B accumulation to 1.45 micrograms per milligram dry weight, approximately 2.4-fold above the untreated control, the strongest effect recorded anywhere in the study. On day 40, however, the picture reversed: 5 micromolar vitexin left justicidin B levels comparable to controls at 1.24 micrograms per milligram dry weight, and 10 micromolar actually produced a slight reduction to 1.01, lower than both the untreated and ethanol-treated controls. This shift demonstrates that the optimal vitexin concentration changes during culture development and that the response is tightly linked to the physiological state of the cultures, with the same dose that strongly supports accumulation at one stage potentially inhibiting the phenylpropanoid pathway at a later one.

The mechanistic hypothesis the authors propose is what makes the study conceptually novel. Vitexin is not a direct biosynthetic precursor of justicidin B, so the observed increases cannot be explained by precursor feeding in the classical sense. Instead, the external supply of vitexin may act through feedback-related modulation of the flavonoid branch of the phenylpropanoid pathway: flooding the cultures with a flavonoid end product may suppress or partially block further metabolic activity toward flavonoid biosynthesis, allowing shared phenylpropanoid intermediates such as coniferyl alcohol to be preferentially directed toward the lignan branch and ultimately toward arylnaphthalene lignan production. In effect, inhibiting a competitive metabolic pathway promotes justicidin B accumulation, exactly as the study’s title suggests. The cultivation-stage-dependent response in L. austriacum further indicates that this redirection is influenced by the physiological state of the cultures and by the applied concentration, emphasizing the importance of optimizing both treatment timing and dose.

The authors are careful to stress that this mechanism remains hypothetical. Future experiments should include targeted metabolomic profiling of flavonoid and lignan intermediates, expression analysis of key genes involved in both branches, and enzyme activity assays for relevant phenylpropanoid pathway enzymes to clarify whether the increased justicidin B accumulation truly results from redirected metabolic activity toward arylnaphthalene lignan biosynthesis. Such analyses would confirm whether exogenous flavonoid supplementation suppresses flavonoid biosynthesis and promotes justicidin B production at the molecular and enzymatic levels, converting a promising correlation into a demonstrated regulatory interaction.

Even with that caveat, the practical implications are considerable. To the best of current knowledge, this is the first study demonstrating that exogenous supplementation with the flavonoid vitexin can influence justicidin B accumulation in Linum root cultures, introducing a novel strategy for enhancing arylnaphthalene lignan production through flavonoid-mediated regulation of the phenylpropanoid pathway. The findings highlight the importance of species-specific metabolic capacity, vitexin concentration, and treatment timing, with L. austriacum root cultures treated with 10 micromolar vitexin on day 30 delivering the highest fold increase in the study. For a compound with such pronounced pharmacological potential and such limited natural availability, a controlled in vitro system that can be steered toward higher lignan output by a single well-timed flavonoid supplement represents a meaningful step toward sustainable biotechnological production, and it opens a new line of inquiry into how the competing branches of one of plant biology’s central metabolic networks can be manipulated by the very molecules they produce.

Subject of Research: Flavonoid-mediated metabolic rerouting enhances anticancer lignan production in Linum root cultures

Article Title: Inhibition of competitive metabolic pathways promotes lignan accumulation in Linum in vitro root cultures

Article References: Zarev, Y., Nedelcheva, R., & Ionkova, I. (2026). Inhibition of competitive metabolic pathways promotes lignan accumulation in Linum in vitro root cultures. Pharmacia, 73, Article e206408. https://doi.org/10.3897/pharmacia.73.e206408

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e206408

Keywords: lignans, justicidin B, Linum, vitexin, phenylpropanoid pathway, plant biotechnology, in vitro root cultures, secondary metabolites, Inhibition, competitive, metabolic, pathways

The research, led by Tolga Bozkurt and colleagues at Imperial College London together with collaborators including Chih-Horng Kuo, Erh-Min Lai, Jiorgos Kourelis, and Lida Derevnina, positions AS109 as what the authors describe as an accessible and versatile chassis for functional genomics in non-model crops. The significance of that claim lies in the widening gap it addresses. Modern genomics generates candidate genes at a pace that far outstrips the capacity of stable transformation to test them, particularly in crop species where regeneration protocols are slow, expensive, or simply unavailable. A transient expression system that works across families would allow researchers to move from hypothesis to experimental validation in days rather than seasons.

Agrobacterium-mediated transfer works by exploiting the natural ability of certain soil bacteria to smuggle DNA into plant cells. In transient expression, the delivered construct is not integrated into the genome in a heritable way; instead, it drives temporary production of a protein of interest, typically within two to five days of infiltration. This makes the technique ideal for testing protein localization, reconstituting signaling pathways, screening for molecular recognition events, and dissecting host-pathogen interactions. But host range has always been the constraint. The canonical laboratory strains, derived largely from Agrobacterium tumefaciens isolates, perform well in Nicotiana species and a handful of other solanaceous hosts, while many legumes, brassicas, and other crops respond poorly, if at all, to infection by these strains.

The PLOS Biology team systematically evaluated AS109 across diverse dicot species spanning multiple taxonomic families and found that the engineered Rhizobium strain mediated efficient transient expression where conventional strains faltered. The breadth of the host range is the headline result, but the consistency matters just as much: across the species tested, AS109 outperformed commonly used laboratory agrobacterial strains, suggesting that the advantage is not a niche adaptation to one or two unusual hosts but a general property of the strain’s interaction with plant tissue.

To demonstrate what a broad-host-range chassis makes possible, the researchers built a suite of functional assays in faba bean (Vicia faba), a legume of global agricultural importance that has long lacked accessible rapid assay tools. The assays covered protein localization, allowing researchers to see where a candidate protein travels within faba bean cells; RNA interference-mediated gene silencing, enabling targeted knockdown of endogenous genes to test function; cell-surface elicitor recognition screens, which reveal whether a plant’s immune receptors can detect molecules characteristic of invading pathogens; and nucleotide-binding leucine-rich repeat receptor, or NLR, activation, the intracellular immune signaling events that trigger programmed cell death upon effector recognition.

The fifth assay in the suite pushes into infection cell biology at the host-pathogen interface, the frontier where plant immunity research increasingly operates. Using live-cell imaging approaches refined in model solanaceous systems, researchers can now watch, in faba bean cells, how pathogens attempt to suppress defenses and how resistance proteins respond in real time. Bringing this capability to a non-model crop transforms faba bean from a species studied mainly through forward genetics and field trials into one amenable to the same mechanistic cell biology that has accelerated discovery in Arabidopsis and Nicotiana benthamiana.

Among the most consequential demonstrations is the cross-family transferability of disease-resistance genes. NLR proteins are the intracellular immune receptors that plants use to detect pathogen effectors, and engineering broad-spectrum resistance increasingly depends on moving NLRs between species. The team showed that both singleton NLRs and sensor-helper NLR pairs—two-member systems in which one receptor perceives the pathogen effector and a partner propagates the signal—originating from the Solanaceae retain their effector recognition and cell death activity when transferred into faba bean. In practical terms, this means a researcher can take a resistance gene characterized in potato or tomato and, within days, test in faba bean whether it recognizes the corresponding effector and mounts the appropriate immune response.

That result has implications well beyond faba bean. Sensor-helper NLR pairs are architecturally complex, requiring coordinated expression and physical interaction, so their successful reconstitution in a distantly related legume suggests that the cellular machinery supporting NLR signaling is more conserved across families than pessimistic assessments had assumed. For crop protection, the AS109 platform offers a rapid pre-screen: before committing years to stable transformation of a candidate resistance gene into a crop, breeders and biotechnologists can evaluate its recognition specificity and signaling competence in a transient assay, triaging candidates that would otherwise consume resources without delivering durable resistance.

The study also speaks to a structural problem in plant science. Research infrastructure has concentrated on a small number of model species, so the tools, protocols, and reference strains are optimized for them, while orphan crops and regionally important staples lag behind. The authors frame AS109 as bridging the gap between hypothesis generation and experimental validation across diverse plant species, and the phrase captures a genuine bottleneck. As genome assemblies and gene annotations accumulate for crops such as faba bean, the limiting step is no longer identifying candidate genes but testing what they do. A chassis that accepts diverse hosts converts that bottleneck from a multi-year transformation cycle into an experiment of days.

What remains to be seen is how the community adopts and extends the platform. The authors present AS109 as accessible, and its performance across families suggests immediate utility for labs working on legumes and other previously underserved dicots. Monocots, which include the cereal crops that supply the majority of human calories, present distinct barriers to Agrobacterium-mediated transfer and were not the focus of this study, so the broad-host-range claim is best understood within the dicot lineage it demonstrates. Even so, for the families it covers, the arrival of a strain that reliably outperforms standard laboratory agrobacteria across species boundaries redefines what a routine experiment in crop biology can look like—moving functional genomics for non-model crops closer to the speed and flexibility that model systems have long enjoyed.

Subject of Research: Broad-host-range Rhizobium rhizogenes-mediated transient expression for functional genomics in diverse crop species

Article Title: A broad-host-range Rhizobium rhizogenes strain enables transient expression across diverse crop species

Article References: King, F., Lopez-Agudelo, J. C., Stephens, C., Aung, M. H., Ibrahim, T., Yuen, E. L. H., Chen, A., Eilmann, N., Jenkins, S., Vuolo, C., Swee, Y.-N., Liu, W.-J., Bruty, S., Toghani, A., Kuo, C.-H., Lai, E.-M., Kourelis, J., Derevnina, L., Wu, C.-H., & Bozkurt, T. (2026). A broad-host-range Rhizobium rhizogenes strain enables transient expression across diverse crop species. PLOS Biology, 24(10), e3004010. https://doi.org/10.1371/journal.pbio.3004010

Image Credits: AI Generated

DOI: 10.1371/journal.pbio.3004010

Keywords: Rhizobium rhizogenes, transient expression, Agrobacterium, faba bean, functional genomics, NLR receptors, plant immunity, crop biotechnology, gene silencing, host-pathogen interface, disease resistance, non-model crops

The target of the work was 4-hydroxyphenylpyruvate dioxygenase, or HPPD, an enzyme that sits at a critical junction in plant metabolism. HPPD catalyzes a step in the breakdown of tyrosine that feeds the production of homogentisate, a precursor required for plastoquinone and tocopherol synthesis. Plastoquinone, in turn, is essential for carotenoid biosynthesis, and carotenoids protect the photosynthetic machinery of chloroplasts from oxidative damage. This dependency is exactly what makes HPPD such an effective herbicidal target: compounds that inhibit the enzyme, including widely used triketone herbicides such as mesotrione, starve plants of carotenoids, causing bleaching of newly emerged tissue and ultimately death. Weeds, crops, and everything green in between share this vulnerability, which is why engineering tolerance at the HPPD locus has long been an attractive but difficult proposition.

The difficulty lies in a classic trade-off. Mutations in the coding sequence of HPPD that weaken herbicide binding tend also to compromise the enzyme’s catalytic performance, because the herbicide-binding pocket overlaps with the chemistry the enzyme must perform. A plant carrying such a mutation may survive spraying, but it pays a growth penalty. Conversely, simply cranking up expression of an unmodified HPPD gene can raise the amount of enzyme available and dilute the herbicide’s effect, but regulatory overexpression often brings pleiotropic problems — metabolic imbalance, developmental defects, and unpredictable performance across genetic backgrounds and environments. The research team behind the new study recognized that dosage-sensitive traits like herbicide tolerance demand simultaneous optimization of both protein function and protein abundance.

Their solution was a dual-layer strategy. On the first layer, they used structure-guided protein design to identify amino acid substitutions in HPPD that would reduce sensitivity to herbicide inhibitors while preserving catalytic activity. Rather than screening random mutagenesis libraries, the researchers reasoned from the three-dimensional structure of the enzyme, focusing on positions that line the inhibitor-binding site but sit at a tolerable distance from the catalytic machinery. This rational approach, informed by computational tools for protein engineering that integrate structural and evolutionary constraints — an area that has advanced rapidly with artificial-intelligence-based inverse-folding models — allowed them to prioritize a small set of candidate substitutions with a high probability of decoupling inhibitor binding from enzymatic function.

On the second layer, the team turned to cis-regulatory engineering at the endogenous HPPD locus. Instead of inserting a transgene under a strong constitutive promoter, they edited the native promoter and regulatory regions of the crop’s own HPPD gene to tune its expression upward in the tissues where tolerance matters most. Because the edits were made in cis, at the gene’s natural address in the genome, the resulting plants carry modified versions of their own gene rather than foreign DNA constructs. This endogenous approach matters both scientifically and commercially: it preserves native regulation as much as possible, reduces the risk of position effects and silencing that plague transgenic insertions, and may ease the regulatory and public-acceptance pathways for edited crops in jurisdictions that distinguish gene-edited from transgenic plants.

Neither layer alone was sufficient. Coding-sequence edits that conferred reduced herbicide sensitivity produced plants whose tolerance was real but incomplete, while regulatory edits alone raised enzyme levels without addressing the fundamental vulnerability of the wild-type protein to inhibition. It was the combination — an enzyme variant less easily poisoned, produced at elevated levels from its own tuned promoter — that produced the striking tolerance phenotypes. The authors describe these combined versions as elite alleles: single, precisely defined haplotypes at the native locus that deliver a trait at a level useful for breeding, without the need for transgenes or multi-gene stacks.

Demonstrating the strategy in both rice and wheat is a significant part of the result. Rice, a model grass with a compact genome and efficient editing protocols, served as the development platform, but wheat presents a far harder engineering challenge because of its large polyploid genome, in which multiple homoeologous copies of genes must often be edited in concert to see an effect. That the dual-layer approach transferred between these two species suggests it is not a quirk of one crop’s genetics but a generalizable design principle for engineering dosage-sensitive traits — traits whose performance depends on getting both the quality and the quantity of a gene product right.

The implications extend well beyond herbicide tolerance. Herbicide-resistant weeds are a mounting global problem, documented across hundreds of species and virtually every major herbicide class, and new tolerance traits are needed both to replace overused chemistries and to enable rotation between different modes of action — a practice that slows the evolution of resistance in weed populations. An HPPD-based tolerance allele generated by editing native sequences could be introduced into elite breeding lines by conventional crossing once created in a donor background, or recreated directly in elite germplasm by editing, dramatically shortening the path from discovery to farmers’ fields compared with transgenic trait development.

More broadly, the study offers a template for how genome editing in crops is maturing. Early editing work largely mimicked loss-of-function genetics, knocking out genes to study their roles or eliminate undesirable traits. The frontier is now precision gain-of-function engineering: redesigning proteins in place, tuning their expression from native regulatory landscapes, and combining these edits into coherent alleles that behave predictably. The same dual-layer logic could apply to other dosage-sensitive agricultural targets, including disease resistance genes, nutrient biosynthetic pathways, and tolerance to drought, salinity, or heat, where both the biochemical properties of a protein and the amount of it a tissue produces determine the phenotype.

Challenges remain before elite HPPD alleles reach commercial reality. Edited crops must clear regulatory review in each market, and the agronomic performance of tolerance alleles must be validated across seasons, soils, and herbicide application regimes. Fitness costs of modified enzyme variants, if any, will need to be quantified over full crop lifecycles, and stewardship plans will be required to manage resistance evolution in weed populations exposed to HPPD-inhibiting chemistry. Yet the conceptual advance is clear and consequential: by treating a gene’s coding sequence and its regulatory architecture as a single coordinated design problem, plant biologists have shown that traits once requiring transgenic stacks can be built into the crop’s own genome, one precisely placed edit at a time. For a world that needs higher yields on finite land under intensifying weed pressure, that is a blueprint worth watching closely.

Subject of Research: Dual-layer genome editing of coding and cis-regulatory sequences at the HPPD locus to engineer herbicide-tolerant rice and wheat

Article Title: Coordinated editing of coding and regulatory sequences creates elite herbicide-tolerant alleles

Article References: Coordinated editing of coding and regulatory sequences creates elite herbicide-tolerant alleles. (2026). Nature Plants. https://doi.org/10.1038/s41477-026-02426-1 (Author names are not included in the publisher’s citation export.)

Image Credits: AI Generated

DOI: 10.1038/s41477-026-02426-1

Keywords: genome editing, herbicide tolerance, HPPD, rice, wheat, cis-regulatory engineering, protein design, crop breeding, gene editing, plant biotechnology, elite alleles, Nature Plants

Cytochrome P450s are often described as the chemistry set of the plant world. These heme-containing enzymes catalyze an extraordinary range of oxidation reactions, decorating simple carbon skeletons with hydroxyl groups and other modifications that transform them into hormones, pigments, fragrances, and defensive toxins. In humans, P450s are famous for metabolizing drugs; in plants, they are the architects of specialized metabolism, the vast chemical repertoire that helps a rooted organism attract pollinators, deter herbivores, and cope with a hostile environment. Because a single P450 can redirect an entire biosynthetic pathway, knowing exactly which P450 genes a species carries, and where they sit in the genome, is a powerful starting point for understanding and eventually manipulating its chemistry.

Dendrobium nobile makes an especially compelling target. As one of the most valued species in traditional Chinese medicine, it accumulates a suite of alkaloids and sesquiterpenes whose biosynthesis has remained largely unmapped at the genetic level. Picrotoxane-type sesquiterpene alkaloids, in particular, share structural themes with picrotoxin, a compound long used in neuroscience research to block inhibitory receptors. Yet the enzymatic steps that assemble these molecules in the orchid, and the genes that perform the late-stage oxidation chemistry, have been almost entirely unknown. The new study set out to close that gap by treating the entire P450 superfamily as a searchable inventory rather than chasing individual enzymes one at a time.

The scale of the inventory is itself notable. Using the published D. nobile genome, the researchers systematically scanned for P450 sequences and confirmed 242 functional genes, which they named DnCYPs according to standard nomenclature. Phylogenetic analysis sorted these proteins into 39 families distributed across the nine major clans that define the plant P450 landscape, from the sprawling CYP71 clan, which specializes in defensive and aromatic compounds, to the CYP86 and CYP97 clans involved in cuticle lipids and carotenoid metabolism. Motif analysis and gene-structure comparisons showed the expected conserved architecture, including the oxygen-binding pocket and heme-binding signature that define the family, while chromosomal mapping revealed that the genes are not scattered randomly across the orchid’s chromosomes but cluster in hotspots shaped by duplication.

Those duplication patterns tell an evolutionary story. The team documented tandem duplication events, in which a gene is copied side by side with its original, in several families, most prominently CYP71, CYP72, CYP76, CYP81, CYP92, and CYP704. Tandem duplicates are evolutionarily significant because they can diverge rapidly, with one copy retaining the ancestral function while the other drifts toward a new substrate or expression pattern. In plants known for chemical novelty, this process is a classic engine of metabolic innovation. The finding suggests that D. nobile’s capacity to synthesize unusual alkaloids may rest, in part, on repeated local expansions of its P450 arsenal during the orchid lineage’s history.

One discovery stands out as a genuine orchid-specific signature. Among all the species the researchers compared, genes of the CYP71K subfamily were detected only in orchids, and D. nobile carried more of them than the other Dendrobium species analyzed. This lineage-restricted expansion hints that CYP71K enzymes may underpin chemical traits unique to the orchid family, possibly including the alkaloid chemistry for which Dendrobium is prized. Subfamily-level specificity of this kind is exactly the kind of clue metabolic biologists look for when hunting for the enzymes responsible for a plant’s most distinctive molecules, because a gene family present only in the species that makes the compound is a natural suspect.

The strongest leads came from combining genome position with expression data. Five genes, DnCYP71K30, DnCYP71K32, DnCYP71K33, DnCYP71K34, and DnCYP71B1, all reside on chromosome 15, and their transcript levels across different tissues rose and fell in step with upstream genes of the picrotoxane-type sesquiterpene alkaloid pathway, including DnHMGR, a key enzyme of the mevalonate pathway that supplies the building blocks for sesquiterpenes, and various DnTPS terpene synthases that assemble the carbon skeletons. Coordinated expression is not proof of function, but it is a powerful filter: enzymes acting in the same biosynthetic route are typically switched on together in the tissues where the compound accumulates. The researchers also measured picrotoxane-type sesquiterpenoid alkaloid content in stems and flowers, anchoring the expression patterns to actual chemistry.

Stress added a second dimension to the story. RNA sequencing under four treatments, methyl jasmonate application, drought, low temperature, and high temperature, identified a subset of DnCYP genes whose transcript abundance shifted in response to these challenges. Scanning the DNA sequences upstream of these genes, the team found putative stress-responsive cis-regulatory elements, the short motifs that transcription factors recognize to dial gene expression up or down under environmental pressure. For selected genes, quantitative reverse-transcription PCR confirmed the direction of the expression changes seen in the RNA-seq data, a standard validation step that strengthens confidence in the sequencing results. Together, these findings suggest that some of the same enzymes that build medicinal compounds may also participate in the orchid’s response to a changing environment, a dual role increasingly recognized in plant specialized metabolism.

The practical implications reach from the greenhouse to the laboratory bench. For breeders and growers in Guizhou and beyond, the study provides candidate markers that could eventually be used to select orchid lines with higher alkaloid content or improved stress tolerance, both traits of direct economic value in a crop whose quality is judged by its chemistry. For synthetic biologists, the chromosome 15 cluster and the orchid-specific CYP71K expansion offer a shortlist of enzymes to test for roles in assembling picrotoxane-type scaffolds, work that could one day enable production of these molecules in engineered microbes or plant hosts. The authors are careful to note the essential caveat: every candidate identified here is a hypothesis. Biochemical function must be confirmed directly, through heterologous expression and enzyme assays or gene editing, before any of the 242 DnCYPs can be assigned a definitive role.

Even so, the study illustrates how a systematic, family-wide approach can transform an obscure biosynthetic puzzle into a tractable research program. Rather than waiting for chemists to isolate an enzyme from orchid stems, the Guizhou team inverted the process, using the genome to nominate suspects and expression patterns to rank them. As genome sequences accumulate for other medicinal plants, this strategy, catalogue the enzyme superfamily, map the duplications, correlate expression with chemistry, and stress-test the candidates, is likely to become the standard playbook. For Dendrobium nobile, an orchid that has been prized for two thousand years, the genetic instructions for its most valuable chemistry are finally coming into focus, one P450 at a time.

Subject of Research: Cytochrome P450 gene family evolution and specialized metabolism in the medicinal orchid Dendrobium nobile

Article Title: Genome-wide characterization of the cytochrome P450 superfamily reveals candidate genes associated with specialized metabolism and abiotic stress responses in Dendrobium nobile

Article References: Wang, B. J., Luo, C., Zhou, X., Fu, S., Wang, H., Wang, X., & Li, D. (2026). Genome-wide characterization of the cytochrome P450 superfamily reveals candidate genes associated with specialized metabolism and abiotic stress responses in Dendrobium nobile. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10026-6

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10026-6

Keywords: Dendrobium nobile, cytochrome P450, specialized metabolism, sesquiterpene alkaloids, picrotoxane, abiotic stress, gene duplication, orchid genomics, methyl jasmonate, terpene synthase, gene expression, plant biotechnology

The logic behind the experiment rests on a biological paradox. Soybean, Glycine max, is a staple of global agriculture, supplying vegetable oil and animal feed protein on a massive scale, yet it is notoriously sensitive to the twin abiotic stresses of drought and soil salinity, both of which are expanding as climates shift and irrigation practices concentrate salts in farmland. Deinococcus radiodurans, by contrast, is a microbial celebrity, renowned for its uncanny ability to reassemble a shattered genome after irradiation and to withstand desiccation, oxidative damage, and other assaults that destroy most living cells. Its arsenal of protective proteins has long intrigued biologists, and the gene DR1372 is one piece of that arsenal, implicated in the bacterium’s extreme stress tolerance. What remained unknown was whether that microbial protection could function inside the cells of a crop plant.

To find out, the team cloned DR1372 from D. radiodurans and engineered soybean plants to overexpress it, then subjected the transgenic lines and ordinary wild-type plants to controlled salt and drought treatments. The comparison produced some of the clearest physiological evidence yet that a bacterial stress protein can meaningfully rewiring a plant’s defenses. Under salt stress, the transgenic lines mounted a dramatically stronger antioxidant response than their unmodified counterparts: superoxide dismutase activity rose by approximately 51.8 percent and peroxidase activity by about 93.4 percent relative to wild type. These two enzymes form a critical first line of defense against reactive oxygen species, the toxic molecules that flood plant cells when salt, drought, or heat disrupt normal metabolism.

The damage-side numbers told an equally compelling story. Malondialdehyde, or MDA, is a standard chemical marker of lipid peroxidation—the destruction of cell membranes by reactive oxygen species—and lower MDA means less membrane injury. In the transgenic lines, MDA content fell by 26.7 percent in one engineered line, designated OE-11, and by 41.6 percent in another, OE-38, compared with wild-type plants under salt stress. In other words, the bacterial gene did not merely strengthen the enzymatic antioxidant shield; it measurably reduced the cellular wreckage that salt stress inflicts on soybean membranes, preserving the structural integrity of cells under conditions that normally degrade them.

Drought told a similar tale of enhanced survival. After the researchers withheld water and then rehydrated the plants, the survival rate of the DR1372-overexpressing lines was three times that of the wild type. For a crop whose yields can collapse in dry seasons, that kind of survival differential is not a subtle laboratory effect; it is the difference between a field that recovers after a dry spell and one that must be replanted. The authors caution that these results were obtained under controlled salt and drought conditions, so the next challenge is confirming that the advantage holds in open-field environments, where stress arrives in unpredictable combinations and intensities.

What makes the study particularly valuable to plant biologists is that the physiological measurements were paired with transcriptome analysis, an RNA-sequencing survey that reveals which suites of genes the transgenic plants switch on under stress. That molecular snapshot showed DR1372 acting not as a single-purpose shield but as a broad regulatory influence. Under drought conditions, the gene upregulated photosynthesis-related pathways, suggesting the engineered plants keep their light-harvesting and carbon-fixing machinery running when water scarcity would normally force them to throttle photosynthesis down. Under salt stress, the transgenic plants boosted brassinosteroid biosynthesis, tapping into a plant hormone family long associated with stress resilience, growth regulation, and the alleviation of oxidative damage.

These transcriptomic findings connect DR1372 to well-established threads in plant stress biology. Brassinosteroids have been shown in numerous studies to help plants manage reactive oxygen species and maintain growth under adversity, and preserving photosynthetic capacity during drought is a central goal of crop improvement, because a plant that keeps photosynthesizing keeps growing even as its neighbors shut down. By nudging both pathways upward, the bacterial gene appears to shift the soybean’s stress response from a passive posture of damage limitation toward an active program of maintained function. The combined physiological and transcriptomic data, the authors note, provide new insight into the biological roles DR1372 can play once placed in a plant context, something that had rarely been reported before this work.

The broader significance lies in the strategy itself. Most transgenic approaches to stress tolerance in soybean have drawn on plant transcription factors—regulatory proteins such as GmDREB1, GmWRKY16, or members of the NAC and bZIP families—or on protective proteins like late embryogenesis abundant, or LEA, proteins from plants. Borrowing a gene from a bacterium best known for surviving nuclear-radiation-level damage represents a bolder cross-kingdom bet, and one that appears to have paid off. Deinococcus proteins evolved under selection pressures far more extreme than any soybean field will ever present, and DR1372 evidently performs compatibly within plant cellular biochemistry, interfacing productively with antioxidant systems and hormone pathways that soybean already possesses. The study thus adds to a growing body of work, sometimes described as climate-resilient microbial biotechnology, that treats microorganisms as a deep reservoir of stress-hardy genes for agriculture.

There are, of course, the usual caveats that separate a promising greenhouse result from a farmer’s harvest. The experiments described were performed on specific transgenic lines under laboratory conditions, and yield, seed quality, and agronomic performance in the field remain to be demonstrated. Regulatory approval for a soybean carrying a bacterial gene would face the same public and policy scrutiny as any transgenic crop. Still, the researchers conclude that DR1372 acts as a positive regulator of both salt and drought tolerance in soybean, making it a promising candidate gene for the genetic improvement of abiotic stress tolerance in the crop. As droughts intensify and saline soils spread across the world’s breadbaskets, the idea that a radiation-proof microbe’s survival kit can be grafted onto the soybean genome is exactly the kind of unconventional thinking that stress-tolerant agriculture may increasingly depend on. The research was supported by China’s National Key R&D Program, the National Natural Science Foundation of China, and related programs, reflecting the country’s substantial investment in stress-resilient crop breeding.

Subject of Research: Transferring the Deinococcus radiodurans DR1372 gene into soybean to improve salt and drought tolerance

Article Title: Overexpression of DR1372 gene from Deinococcus radiodurans improves the salt and drought tolerance in soybean

Article References: Zhou, L., Zang, K., Liu, X., Wang, P., Guo, W., Su, X., Afridi, M., Wang, J., Lin, M., Cheng, H., & Guo, H. (2026). Overexpression of DR1372 gene from Deinococcus radiodurans improves the salt and drought tolerance in soybean. Plant and Soil. https://doi.org/10.1007/s11104-026-09038-w

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09038-w

Keywords: Deinococcus radiodurans, DR1372, soybean, drought tolerance, salt stress, transgenic plants, antioxidant enzymes, brassinosteroids, photosynthesis, abiotic stress, plant biotechnology, transcriptomics

The team focused on a gene called lemon white1, or lw1, a key regulator of chlorophyll and carotenoid biosynthesis. The choice was strategic. When lw1 function is knocked out across enough gene copies, the resulting plants display a pale, yellowish foliage that can be scored visually, giving the researchers an immediate, unambiguous readout of whether their editing constructs were actually working in a genome where sequencing every allele is a formidable chore. Visible markers of this kind have become a favorite calibration tool in polyploid crop editing, and the sugarcane community had previously used a magnesium chelatase gene for the same purpose with Cas9. Extending the approach to Cas12a, however, required solving several technical problems at once.

Cas12a, originally characterized as Cpf1, differs from the more familiar Cas9 nuclease in ways that matter for crops like sugarcane. It recognizes a T-rich DNA motif called a PAM, which makes it particularly well suited for targeting AT-rich genomic regions, including many cis-regulatory elements that control when and where genes are switched on. It also produces staggered DNA cuts and processes its own guide RNAs, simplifying multiplexed editing. Until now, despite these advantages, Cas12a had never been demonstrated in sugarcane. The Florida group compared two engineered versions of the Lachnospiraceae bacterium-derived enzyme: an intron-containing LbCas12a-R variant, in which added intron sequences boost expression in plant cells, and LbCas12a-RRV, a more recently developed high-activity variant.

The results were striking. Editing efficiencies across the experimental lines ranged from 31 to 85 percent, and the LbCas12a-RRV variant consistently outperformed the intron-containing LbCas12a-R in both overall editing frequency and the proportion of alleles edited within individual plants. In a genome where every gene may be present in a dozen or more copies, allelic editing efficiency, the fraction of homologous copies that carry a mutation, is the metric that ultimately determines whether an edited phenotype appears at all. The demonstration that a modern Cas12a variant can push multiallelic disruption to visually scorable levels in sugarcane opens a substantially larger fraction of the genome to precision editing, particularly the AT-rich promoter and enhancer regions that Cas9 systems reach less comfortably.

The second half of the study addresses a problem that goes beyond efficiency: the size of the edits themselves. Standard CRISPR cutting typically produces small insertions and deletions as the cell repairs the break, and in a polyploid genome these tiny changes can be difficult to detect and may not fully abolish gene function. The researchers therefore co-expressed mTREX2, the mouse version of Three prime repair exonuclease 2, alongside the Cas12a machinery. TREX2 is a processive exonuclease that chews back DNA ends after the nuclease cut, enlarging the gap that the repair machinery must fill. When the cell reseals the break, the result is a deletion that is often far larger than what standard repair would produce. The strategy has precedent in other systems, where TREX enzymes fused to or co-expressed with Cas nucleases have been shown to enlarge deletion sizes in both plants and human cells, but its application to Cas12a editing in a highly polyploid crop is new.

The effect on the sugarcane mutation spectrum was dramatic. Co-expression of mTREX2 shifted the profile of recovered mutations toward moderate and large deletions, with the class of deletions measuring at least 51 base pairs increasing approximately seven-fold in both Cas12a variants. Larger deletions matter for two reasons. First, they are far more likely to completely disrupt gene function rather than leaving a partially active protein. Second, and arguably more important in polyploids, they are much easier to detect. A deletion of 51 or more base pairs creates a size difference that standard fragment analysis can resolve, even when dozens of unedited homologous copies are present in the same sample. In effect, mTREX2 co-expression converts the hardest part of polyploid genotyping, distinguishing edited from unedited alleles, into a comparatively simple measurement.

That measurement itself was a focus of the study. Rather than relying on next-generation sequencing, which is expensive and computationally demanding when applied to the tangled allele sets of sugarcane, the team used capillary electrophoresis-based genotyping, a fragment analysis approach that separates DNA molecules by size. The method proved to be a cost-effective, high-throughput alternative that accurately predicted both allelic editing efficiency and indel size. For breeding programs and laboratories in sugarcane-producing countries that may not have routine access to deep sequencing infrastructure, this is a practical advance as significant as the editing system itself. It lowers the barrier to screening the hundreds of independent transgenic events that polyploid editing typically requires before a useful line emerges.

The broader significance lies in what Cas12a unlocks for sugarcane improvement. Much of the regulatory information that governs yield, stress tolerance, and sugar accumulation resides in AT-rich cis-regulatory DNA, and fine-tuning those elements, rather than knocking out coding sequences outright, is increasingly recognized as the most sophisticated use of genome editing in crops. Previous work from the same laboratory and others has shown that multiallelic editing of genes such as LIGULELESS1 can tune leaf architecture and biomass yield in sugarcane, and that promoter editing can adjust gene expression levels in rice and maize. A reliable Cas12a platform, especially one enhanced with mTREX2 to generate large deletions, gives breeders a tool for reshaping regulatory landscapes that were previously out of reach, whether the goal is reduced lignin for easier ethanol extraction, altered flowering, or enhanced disease resistance.

The work, funded by the US Department of Energy’s Center for Advanced Bioenergy and Bioproducts Innovation and by the USDA National Institute of Food and Agriculture, arrives at a moment when genome editing is accelerating across global crop improvement. Sugarcane occupies a unique position at the intersection of food security and renewable energy, and its genomic complexity has kept it a generation behind rice, wheat, and maize in editing-based improvement. With this study, the crop gains not only a new nuclease platform but also a validated workflow, from construct design through visual phenotyping to affordable genotyping, that other teams working on polyploid crops such as switchgrass, Miscanthus, and potato can adapt. The seven-fold boost in large deletions from a single co-expressed exonuclease suggests that the remaining technical gaps in polyploid editing may be closed not by entirely new technologies, but by clever combinations of components that already exist.

For now, the lemon white1 seedlings glowing pale yellow in the Florida greenhouse stand as proof of concept that Cas12a can function in one of nature’s most demanding genomes. The next steps will be to apply the LbCas12a-RRV and mTREX2 system to agronomically meaningful targets, to test whether large deletions can be directed toward promoter regions for fine-tuned expression changes, and to determine how edited lines perform under field conditions. If those efforts succeed, the study may be remembered as the moment sugarcane, long the most genomically intimidating of the major crops, finally became a tractable target for the full toolkit of modern plant synthetic biology.

Subject of Research: CRISPR/Cas12a genome editing with mTREX2 co-expression in the highly polyploid sugarcane genome

Article Title: mTREX2 co-expression promotes large deletions in CRISPR/Cas12a editing of the highly polyploid sugarcane genome

Article References: Ali, Q., Trujillo, C., & Altpeter, F. (2026). mTREX2 co-expression promotes large deletions in CRISPR/Cas12a editing of the highly polyploid sugarcane genome. Plant Cell Reports, 45(11), Article 328. https://doi.org/10.1007/s00299-026-03935-1

Image Credits: AI Generated

DOI: 10.1007/s00299-026-03935-1

Keywords: sugarcane, CRISPR/Cas12a, mTREX2, LbCas12a-RRV, polyploid genome, genome editing, lw1 gene, large deletions, capillary electrophoresis, plant biotechnology, biofuel feedstock, cis-regulatory elements