The enzymes in question are Δ³,Δ²-enoyl-CoA isomerase (ECI) and Δ³,⁵,Δ²,⁴-dienoyl-CoA isomerase (DCI). Both act as essential auxiliary enzymes in peroxisomal β-oxidation, the core metabolic pathway responsible for fatty acid catabolism and energy replenishment. While the canonical β-oxidation spiral handles saturated fatty acids with ease, unsaturated fatty acids pose a topological problem: their double bonds leave gaps in the pathway that standard enzymes cannot bridge. ECI and DCI fill exactly those gaps, rearranging double bonds so the degradation spiral can continue. Without them, the plant cannot efficiently mobilize unsaturated lipid reserves, a critical process when environmental stress forces rapid energy reallocation.

Using the reference genome of hexaploid wheat cultivar Chinese Spring, the researchers identified 13 TaECI and 5 TaDCI family members. Phylogenetic analysis, gene structure annotation and conserved motif detection revealed high sequence and structural conservation within each subfamily, hinting that members of the same subfamily may perform similar biochemical functions. This kind of conservation is significant in wheat because, as a hexaploid, it carries three homoeologous copies of most genes, one on each of its A, B and D subgenomes. The fact that these copies have retained their structural integrity over millions of years of polyploid evolution suggests that their functions have been actively preserved by natural selection.

Promoter cis-element analysis added a regulatory dimension to the picture. The regions upstream of the TaECI and TaDCI genes are densely populated with cis-regulatory elements associated with phytohormone signaling and abiotic stress responses. This implies that the two gene families are extensively modulated by multiple environmental and hormonal signals, rather than being constitutively expressed housekeeping components. In practical terms, it means the plant can dial these genes up or down depending on what the environment demands, a flexibility that could be exploited in breeding programs aimed at stress-resilient varieties.

To test whether this regulatory potential translates into actual stress-responsive behavior, the team performed quantitative real-time PCR (qRT-PCR) assays under two stress conditions: PEG-simulated osmotic stress, which mimics drought at the cellular level by reducing water availability, and heat stress. The results were strikingly specific. Under PEG-simulated osmotic stress, TaECI4-D was significantly upregulated with a 3.2-fold induction (FDR-adjusted P < 0.01), while TaECI4-A showed a 2.1-fold induction (FDR-adjusted P < 0.05). Under high-temperature stress, TaECI4-B, TaECI4-A, TaDCI1-D and TaDCI1-A were all significantly upregulated at the transcriptional level.

Notably, qRT-PCR validation confirmed that TaECI4-D was significantly upregulated under PEG-simulated osmotic stress, while TaECI4-B, TaDCI1-D and TaDCI1-A were significantly upregulated under heat stress. Only one gene, TaECI4-A, showed positive transcriptional responses to both PEG-simulated osmotic stress and heat stress, making it a dual-stress responsive candidate. This kind of cross-stress responsiveness is exactly what breeders look for when trying to develop varieties that can cope with the unpredictable combination of heat and drought that climate change is increasingly delivering to wheat-growing regions.

Protein-protein interaction network prediction further indicated potential functional coordination between TaECI and TaDCI proteins. The researchers suggest that these proteins may synergistically promote peroxisomal fatty acid degradation, thereby enhancing wheat stress tolerance. This coordination makes biochemical sense: ECI and DCI handle different types of unsaturated fatty acid intermediates, and their cooperation ensures that the full spectrum of unsaturated lipids can be efficiently catabolized when the plant needs to mobilize energy reserves under stress.

The significance of this work extends beyond basic plant biology. Wheat is one of the world’s most important staple crops, feeding billions of people, and high temperature and drought are the predominant abiotic stresses that severely limit wheat yield and productivity worldwide. By systematically characterizing the evolutionary features, structural characteristics and divergent stress-responsive expression patterns of the TaECI and TaDCI gene families, the study provides a foundation for future functional characterization. TaECI4-A, whose induction under both stresses was independently confirmed by qRT-PCR, stands out as a particularly promising candidate for further investigation into wheat responses to multiple abiotic stresses.

What makes this research especially timely is the growing recognition that lipid metabolism is not merely a background process in plant stress responses but a central player. As climate volatility intensifies, understanding how wheat reprograms its fatty acid catabolism under heat and osmotic stress could unlock new strategies for crop improvement. The identification of specific, stress-responsive members of the ECI and DCI families gives researchers concrete molecular targets to manipulate, whether through conventional breeding, marker-assisted selection or genome editing approaches.

The study, published in BMC Plant Biology, was supported by the National Natural Science Foundation of China, the Key Scientific Research Project Plan of Higher Education Institutions in Henan Province, and the National Training Program of Innovation and Entrepreneurship for Undergraduates. As the global demand for climate-resilient wheat continues to grow, this genome-wide characterization of auxiliary β-oxidation enzymes offers a fresh molecular entry point into one of agriculture’s most pressing challenges.

Subject of Research: Genome-wide identification of wheat ECI and DCI gene families linked to heat and osmotic stress response

Article Title: Genome-wide identification and expression profiling of TaECI and TaDCI gene families suggest their potential involvement in wheat response to heat and osmotic stress

Article References: Niu, K.-X., Zhu, S.-L., Gao, H., Ma, Y.-X., Xi, X.-H., Dang, X.-Y., Sun, S.-Y., & Zhao, T.-Y. (2026). Genome-wide identification and expression profiling of TaECI and TaDCI gene families suggest their potential involvement in wheat response to heat and osmotic stress. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10173-w

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10173-w

Keywords: wheat, heat stress, osmotic stress, β-oxidation, gene families, crop stress tolerance, Genome-wide, identification, expression, profiling, TaECI, TaDCI

The research team, led by Zhenhua Lu and Zheng Li of Yunnan University together with collaborators including Laura Ellen Rose of Heinrich-Heine-Universität Düsseldorf, took advantage of a natural experiment that evolution has run repeatedly across the rice genus Oryza. Within this genus, several closely related species pairs exist in which one member is perennial and the other is annual. The researchers compared three such pairs: Oryza rufipogon, a perennial wild relative of cultivated rice, against its annual counterpart Oryza nivara; Oryza glumaepatula, a perennial South American wild rice, against the African cultivated annual Oryza glaberrima; and Oryza meyeriana against Oryza brachyantha. By lining up the genomes of species that have independently converged on annuality, the team could search for genetic changes that recur across these transitions, a far stronger signal than any single species comparison could provide.

The central logic of the study is elegantly simple. If a gene family is retained in every perennial species examined but is absent from every annual species, then its loss is unlikely to be random noise. Across the three pairs, the researchers identified exactly 91 gene families that fit this pattern: present in all three perennials, missing from all three annuals. These 91 families represent the strongest candidates for genetic changes that accompanied or enabled the perennial-to-annual transition, and they now form a curated shortlist for anyone seeking the molecular basis of plant life history.

What do these lost genes actually do? Functional annotation and prediction of the 91 families suggested that they are not a random assortment of housekeeping genes. Instead, they map onto a battery of physiological systems that one would expect to matter for a plant that must survive year after year. The categories include phenology, the timing of developmental events such as flowering and dormancy; energy allocation, the decisions about where captured carbon and nutrients are invested; and source–sink dynamics, the coordinated movement of photosynthate from producing tissues such as leaves to consuming tissues such as roots, seeds and storage organs. A perennial plant must budget its resources across multiple reproductive cycles, and the study suggests that annual species shed genes that help manage that long-horizon accounting.

To probe function more deeply, the team went beyond sequence annotation and performed comparative co-expression analysis. Genes rarely act alone; they operate in regulatory networks whose activity patterns reveal their roles. By comparing co-expression relationships between perennial and annual Oryza species, the researchers found that many of the 91 candidate gene families likely participate in orchestrating processes that differ systematically between the two life histories. Three themes stood out: reproduction, root development, and responses to environmental stimuli. Each makes intuitive sense for the perennial-to-annual shift. Annual plants pour resources into a single, terminal flowering event, while perennials must regulate reproduction so that it can recur; perennial roots, which anchor the plant through multiple seasons and store reserves, require developmental programs that annuals can afford to simplify; and a plant that lives for years must continuously adjust to a changing environment rather than timing its entire life cycle to a single season.

The study also examined the regulatory architecture surrounding these candidate genes, analyzing promoter cis-elements and protein motifs, and documented pseudogenes in Oryza nivara, hints of genes decaying into nonfunctional remnants in the annual lineage. While the paper presents these as candidate-level evidence rather than proven causation, the convergence of several independent lines of evidence, presence-absence patterns, functional annotation, enrichment analyses, and co-expression comparisons, strengthens the case that gene loss played a real role in the emergence of annuality in Oryza.

Perhaps the most important conceptual takeaway is that the transition to annuality appears to be evolutionarily complex rather than the product of one or a few master mutations. The 91 gene families touch on a wide range of biological processes, and the co-expression results imply that annual species have rewired regulatory networks across reproduction, root biology and environmental response. This complexity carries a direct message for breeders: improving perennial rice will likely require attending to many aspects of perennial physiology in combination, rather than fixing a single perenniality gene and expecting the whole life-history package to follow. The authors argue that a combinatorial view of perenniality is needed to improve the overall agronomic performance of perennial rice varieties.

The practical stakes are considerable. Perennial rice has already demonstrated potential to alleviate the multidimensional sustainability problems of current rice agriculture, reducing the need for yearly tillage, planting and the associated labor and inputs. But breeding better perennial varieties has been hampered precisely by the limited knowledge of perenniality mechanisms that this study begins to address. By supplying a defined set of candidate gene families, the work gives geneticists concrete targets for functional validation, and gives breeders molecular markers that could be tracked as they combine perennial traits from wild relatives such as Oryza rufipogon with the yield and grain quality of cultivated rice.

Methodologically, the study showcases the power of treating evolution’s replicates seriously. Any single perennial-annual pair might differ for reasons unrelated to life history, such as local adaptation or domestication bottlenecks. But requiring a gene family to be absent from all three annual lineages while present in all three perennials filters out much of that noise. The team supplemented genome comparisons with RNA-sequence data from public archives, measured expression in counts per million, and built co-expression networks in the perennial O. rufipogon that they then connected to modules in cultivated annual rice, allowing them to ask whether the regulatory neighborhoods of candidate genes had been reorganized during the transition. Enrichment analyses against Gene Ontology, Trait Ontology, KEGG pathways, Pfam protein domains and EggNOG orthology groups rounded out the annotation pipeline.

The work, which received support from China’s National Key Research and Development Program, the National Natural Science Foundation of China, Yunnan provincial research programs, the New Cornerstone Science Foundation and Germany’s Excellence Strategy, opens a clear path forward. The next step is experimental: knocking out or transferring individual candidate genes in controlled backgrounds to test whether they genuinely influence perennial traits such as regrowth after harvest, ratooning ability or resource storage. If even a fraction of the 91 families proves functional, the study will have converted a long-standing evolutionary puzzle into an actionable breeding toolkit, bringing the vision of rice fields that never need replanting closer to routine agricultural reality.

Subject of Research: Comparative genomics of perennial-to-annual evolutionary transitions in Oryza rice species

Article Title: Mining genetic changes underlying perennial-to-annual transitions in Oryza with comparative genomics

Article References: Lu, Z., Zhou, Y., Zheng, H., Yang, G., Rose, L. E., Hu, F., & Li, Z. (2026). Mining genetic changes underlying perennial-to-annual transitions in Oryza with comparative genomics. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10041-7

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10041-7

Keywords: Oryza, perennial rice, comparative genomics, gene families, life history evolution, annual plants, co-expression analysis, crop breeding, genome evolution, plant genetics, sustainable agriculture, source-sink dynamics