Researchers systematically assessed four key variables affecting transformation: culture medium, A. rhizogenes strain, seedling age and explant type. The selected protocol used strain K599 for infection and Hoagland-moistened vermiculite as the substrate. This combination produced successful hairy-root induction from all three explant types examined. The study did not describe the exact culture conditions, replicate numbers or statistical uncertainty in the supplied abstract, so the performance of the protocol across additional genotypes and experimental environments cannot be determined from this evidence.

Among nine developmental regulators tested, FsMP co-transformation increased leaf transformation efficiency to 95%. The abstract does not report efficiency values for the other eight regulators, meaning that 95% can be described as the reported performance of FsMP co-transformation but not as a demonstrated maximum across the full comparison. The broader objective was to reduce the low efficiency and long culture cycles associated with conventional A. tumefaciens-mediated transformation, which has hindered genomic and molecular-breeding studies in F. suspensa.

The authors characterized the resulting hairy-root system as a rapid, economical alternative to conventional tissue culture and proposed it as a platform for validating gene function and supporting molecular breeding in F. suspensa and other woody species. These are stated research conclusions rather than demonstrated field or breeding outcomes: the supplied evidence comes from an abstract and does not address genetic stability, regeneration of transformed shoots, field performance or long-term expression. The article was also identified as an early peer-reviewed version subject to further editorial changes.

Subject of Research: Optimization of hairy-root transformation and gene editing in Forsythia suspensa

Article Title: Establishment of a high-efficiency hairy root transformation system for Forsythia suspensa and enhancement of transformation efficiency by developmental regulators

Article References: Li, Q., Shao, Q., Wang, D., Zhang, N., Qiao, Y., & Song, Y. (2026). Establishment of a high-efficiency hairy root transformation system for Forsythia suspensa and enhancement of transformation efficiency by developmental regulators. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09996-4

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09996-4

Keywords: Forsythia suspensa, hairy-root transformation, Agrobacterium rhizogenes, FsMP, CRISPR/Cas9, RUBY reporter, leaf transformation, gene editing, woody plants, molecular breeding, Establishment, high-efficiency

The urgency behind this work stems from a fundamental weakness of modern disease control. Resistant cultivars remain the most effective and environmentally sustainable strategy against Fusarium wilt, because the fungus persists in soil for years and cannot be reliably eliminated by crop rotation or chemical treatment. Yet pathogens are adaptable: when a single resistance gene is deployed across large areas, the fungus can evolve to overcome it. With only a handful of known resistance genes available in pea, breeders have had limited options for rotating or stacking defenses. The identification of PsFwC9 broadens that genetic base in a meaningful way, particularly because the new gene sits on a different chromosome from previously characterized resistance loci and appears to operate through a mechanism distinct from the classical resistance proteins that have dominated plant pathology for decades.

Finding the gene required a combination of large-scale sequencing and painstaking genetic mapping. The researchers began with whole-genome resequencing of the resistant line Chengwan 9-8 and used bulked segregant analysis sequencing, or BSA-seq, a technique that accelerates gene discovery by sequencing pooled DNA from many resistant offspring and many susceptible offspring separately. Variants that consistently differ between the two pools are likely to lie near the gene responsible for the trait. This approach allowed the team to narrow the search to an 817.06 kilobase interval on chromosome 4, where four molecular markers showed complete co-segregation with resistance across the mapping population. Fine mapping then zeroed in on a single candidate gene, Psat4g213640, as the most likely source of the resistance phenotype.

The most striking result came from haplotype analysis across 218 diverse pea accessions. When the researchers compared genetic variants across this broad germplasm panel, exactly one polymorphism was consistently associated with resistance: a single G/A single-nucleotide polymorphism within Psat4g213640. That one-letter difference in the DNA sequence changes a single amino acid in the encoded protein, substituting alanine for threonine at a specific position. Such a seemingly modest change can alter protein folding, stability, or interaction surfaces, and in this case it appears to be the molecular switch that separates resistant plants from susceptible ones. The finding illustrates how enormous phenotypic consequences in agriculture can trace back to the smallest possible unit of genetic variation.

Equally intriguing is where the protein does its work. Subcellular localization studies placed the PsFwC9 protein in the endoplasmic reticulum, the membrane network responsible for folding and processing proteins within the cell. The endoplasmic reticulum has increasingly been recognized as a key player in plant immunity, serving as a hub for the perception of pathogen attack and the trafficking of defense signals, but resistance genes operating from this compartment remain unusual. Notably, the predicted protein lacks the NB-ARC domains that characterize many classic intracellular immune receptors, suggesting that PsFwC9 defends peas through a fundamentally different route than the well-studied resistance genes deployed in crops worldwide.

To confirm that the candidate gene truly causes resistance rather than merely sitting near it, the team turned to functional validation using Agrobacterium rhizogenes-mediated hairy root transformation. When the resistant version of PsFwC9 was overexpressed in the roots of susceptible pea plants, the transformed plants gained significant resistance to Fop race 5, with wilting symptoms delayed by nearly two weeks. In the reciprocal experiment, silencing the gene in resistant plants compromised their defense, leaving them vulnerable to infection. Together, these gain-of-function and loss-of-function results provide strong evidence that Psat4g213640 is the gene underlying the PsFwC9 resistance locus, closing the loop between genetic mapping and biological mechanism.

The practical implications for breeding are immediate. Alongside the gene discovery, the researchers developed a diagnostic molecular marker, designated A016615, that allows breeders to identify the resistance allele directly from a DNA sample. Instead of conducting time-consuming and environmentally dependent disease assays, in which seedlings must be inoculated with the fungus and observed over weeks, breeders can now screen large numbers of plants quickly and accurately for the resistance haplotype. Marker-assisted selection of this kind dramatically shortens the timeline for introducing resistance into elite cultivars, and it enables precise tracking of the gene through multiple generations of crossing.

Beyond single-gene deployment, the discovery lays the groundwork for gene pyramiding, the practice of combining multiple resistance genes within a single variety. Because PsFwC9 resides on chromosome 4 and differs in both location and likely mechanism from previously known Fusarium wilt resistance genes, it can be stacked with existing genes to create varieties that the pathogen would need to defeat several times over simultaneously. Durable resistance of this kind is the holy grail of disease breeding, since it reduces the evolutionary pressure on the pathogen to adapt and extends the useful lifespan of each individual gene. The authors emphasized that the identification of PsFwC9 adds a valuable new tool to the pea breeder’s toolbox and opens new possibilities for understanding how peas defend themselves against vascular pathogens.

The broader scientific significance extends past peas. Fusarium oxysporum is a species complex that attacks hundreds of crops, from tomatoes and bananas to melons and cabbages, and vascular wilt diseases remain among the hardest plant diseases to manage. An ER-localized resistance protein working independently of NB-ARC domains adds to a growing body of evidence that plant immunity is more mechanistically diverse than textbook models suggest. Understanding how a single amino acid substitution in an endoplasmic reticulum protein translates into near-total protection against a lethal vascular fungus could inform resistance strategies in other crops facing related pathogens, and may reveal conserved immune pathways that have gone unnoticed under the shadow of canonical resistance genes.

As global demand for plant protein rises, peas occupy an increasingly important place in sustainable cropping systems, fixing nitrogen and enriching soils while feeding people and livestock. Protecting that role against Fusarium wilt requires exactly the kind of work this team has delivered: a precisely mapped gene, a validated mechanism, and a ready-to-use diagnostic marker. The research, published in Horticulture Research and supported by the China Agriculture Research System, the National Key R&D Program of China, and related funding programs, transforms a devastating disease problem into a tractable breeding challenge. For growers watching their fields wilt year after year, a single letter of DNA may soon make the difference between loss and harvest.

Subject of Research: Identification of the PsFwC9 gene conferring resistance to Fusarium wilt in pea

Article Title: A single gene change turns susceptible peas into fusarium wilt fighters

Article References: A single gene change turns susceptible peas into fusarium wilt fighters. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: pea, Fusarium wilt, Fusarium oxysporum, PsFwC9, plant resistance gene, BSA-seq, haplotype analysis, hairy root transformation, marker-assisted selection, gene pyramiding, endoplasmic reticulum, plant immunity

The research, led by Luying Chen and Shaojie Han of Zhejiang University together with colleagues at Northeast Agricultural University and Purdue University, centers on a mixture the team calls Agrobacterium Auxiliary Solution, or AAS. The solution combines B5 medium, sucrose, a MES buffering salt, the surfactant Silwet L-77, acetosyringone, and two plant hormones, the cytokinin 6-benzylaminopurine and gibberellin A3. Each ingredient has a rationale. Acetosyringone is a phenolic compound that induces the virulence genes Agrobacterium needs to transfer DNA into plant cells. The hormones encourage wounded tissues to regenerate roots. Silwet L-77, a detergent famously used in the floral-dip transformation of Arabidopsis, reduces surface tension so that the bacterial suspension can infiltrate plant surfaces and reach cells at wound sites.

To measure whether the solution actually worked, the researchers first had to solve a detection problem. Soybean roots naturally autofluoresce, which makes conventional green and red fluorescent protein markers difficult to distinguish from background signal. The team therefore built a panel of reporter vectors using Golden Gate assembly into the pAGM4673 binary backbone, all driven by a double cauliflower mosaic virus 35S promoter. Two of these carried the brighter fluorescent proteins ZsGreen and TdTomato, which proved clearly distinguishable from the roots’ own fluorescence under a stereomicroscope. The third was based on the Ruby reporter system, which packages the three betalain biosynthesis enzymes CYP76AD1, DODA, and glucosyltransferase into a single open reading frame. Because tyrosine, the substrate for betalain synthesis, is present in every plant cell, Ruby-positive roots turn visibly red without any microscope at all.

With reporters in hand, the team tested AAS on the cotyledon transformation method, in which excised soybean cotyledons are infected with Agrobacterium rhizogenes strain Ar.Qual and induced to sprout transgenic hairy roots. In the variety Wandou 28, adding only the hormone mixture to the solution produced a modest, statistically insignificant increase of roughly 1.9-fold in the proportion of positive roots among total roots. But when Silwet L-77 was included alongside the hormones, the transformation efficiency jumped to about 3.8 times the untreated control. The same pattern held when the researchers scored cotyledons rather than individual roots: the hormone mixture alone gave a 2.5-fold increase in the fraction of cotyledons producing positive roots, while hormones plus surfactant delivered a 4.0-fold enhancement. The combined treatment also raised the overall rate at which cotyledons produced any hairy roots at all, by about 1.4-fold, indicating that the solution stimulates both infection and regeneration.

Crucially, the benefit was not confined to a single variety. When the team applied AAS across Zhonghuang 39, Williams 82, Forrest, and Wandou 28, positive root conversion rates rose three to four times above baseline in every genotype tested. The effect on overall root induction varied more by variety; in Zhonghuang 39 and Williams 82 the proportion of cotyledons making roots was not significantly changed, whereas in Forrest and Wandou 28 it was. Even so, the consistent boost in positive transformation across genotypes suggests the solution addresses a bottleneck that is common to soybean rather than an idiosyncrasy of one cultivar. The full workflow, from seed sterilization to scored hairy roots, takes only about 22 days, and the cotyledon method routinely converted 90 to 99 percent of infected explants into hairy-root producers, of which 30 to 60 percent were genuinely transgenic.

The study also uncovered a variable that transformation protocols rarely discuss explicitly: the size of the DNA payload. Markers such as GFP, at under one kilobase, and GUS, at roughly two kilobases, historically yielded high transformation rates. But when the researchers used the full three-gene Ruby cassette, totaling about four kilobases, efficiency dropped sharply. GFP and RFP constructs achieved root transformation efficiencies around 52 percent, while Ruby 1+2+3 managed only about 29 percent. At the cotyledon level the gap was similar, with fluorescent markers reaching 89 to 96 percent positive rates and the full Ruby cassette falling to 64 percent. A truncated two-gene version, Ruby 1+2, which still produces a red-root phenotype at 2.3 kilobases, performed better than the full cassette, confirming a size-dependent trend rather than a quirk of the betalain system itself.

The team pushed this observation further with a co-transformation experiment, splitting the Ruby system across two separate binary vectors, one carrying Ruby 1+2 and the other Ruby 3, and mixing two Agrobacterium strains to deliver both. A root only turned red if both vectors landed in the same cell, making co-transformation directly visible. The two-vector approach worked, producing red roots indistinguishable from those made by the single full-length cassette, but the efficiency was slightly yet significantly lower than the single-vector version, and fewer cotyledons produced roots at all. For researchers designing multi-gene constructs or genome-editing payloads, the message is clear: every additional kilobase and every extra vector carries a measurable cost, and compact designs will pay dividends in recovery of transgenic material.

AAS proved equally valuable in a second, even simpler system. In the hypocotyl method, used to generate so-called composite soybean plants with transgenic roots on wild-type shoots, six-day-old seedlings are soaked in an Agrobacterium suspension and then cut just below the cotyledons, allowing the solution to be drawn into the stem. This approach requires no sterile facilities at all. Testing Williams 82, Forrest, and Dongnong 50 with both Ruby vectors, the researchers found that AAS consistently raised both the positive root efficiency and the positive explant efficiency. Varietal differences were pronounced, with Forrest behaving distinctly from Williams 82 and Dongnong 50, a reminder that genotype remains a major determinant even with an optimized protocol. Interestingly, the strain Ar.Qual, which performed well on cotyledons, failed entirely in the hypocotyl system, underscoring that strain choice and tissue context matter as much as the additives themselves.

Perhaps most significantly for the future of stable soybean engineering, AAS also improved the classic Agrobacterium tumefaciens-mediated cotyledonary node transformation, the workhorse method for producing fully transgenic plants. Using the pCAMBIA3301-GUS vector with A. tumefaciens strain EHA105 on the variety Dongnong 50, the team found that adding AAS raised the GUS staining rate in cotyledons from 45.8 percent to 73.4 percent, and the staining rate in adventitious shoots from 43.2 percent to 67.5 percent. Because cotyledonary node transformation is the gateway to heritable, whole-plant lines, an improvement of this magnitude could shorten the timelines that currently make soybean functional genomics and genome editing so laborious.

The broader implications extend beyond soybean. Transgenic hairy roots generated by these systems are versatile tools for protein expression, subcellular localization, bimolecular fluorescence complementation, and the screening of guide RNAs before committing to full CRISPR/Cas9 plant production. The hairy root approach has already been adapted in tomato and other species, and the authors suggest the AAS-enhanced protocol could be tuned for root biology studies across a wide range of plant genotypes. For a crop in which narrow genetic diversity and long breeding cycles have slowed both basic research and applied improvement, a cheap, mix-and-soak solution that reliably multiplies transformation efficiency is the kind of unglamorous but consequential advance on which much of modern plant biotechnology depends.

Subject of Research: Improving Agrobacterium-mediated soybean transformation efficiency using an auxiliary solution with surfactant and plant hormones

Article Title: Enhancing Agrobacterium-mediated soybean transformation efficiency with an auxiliary solution

Article References: Chen, L., Wang, L., Zhang, L., Li, Y., & Han, S. (2024). Enhancing Agrobacterium-mediated soybean transformation efficiency with an auxiliary solution. Crop Health, 2(1), Article 17. https://doi.org/10.1007/s44297-024-00037-w

Image Credits: AI Generated

DOI: 10.1007/s44297-024-00037-w

Keywords: soybean, Agrobacterium rhizogenes, hairy root transformation, Silwet L-77, Ruby reporter, plant hormones, genetic transformation, cotyledon transformation, hypocotyl transformation, plant biotechnology, GUS assay, vector size