ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Pathogen Interactions
This article is part of the Research TopicPlant Molecular Biology and Microbiome Engineering: Next-Generation Strategies for Multi-Stress ResilienceView all 6 articles
Genome-wide Analysis of Soybean Cinnamyl Alcohol Dehydrogenase Genes Identifies GmCAD3 as a Positive Regulator of Fusarium oxysporum Resistance
Provisionally accepted
- 1Soybean Research Institute, Heilongjiang Academy of Agricultural Sciences, Harbin, China
- 2Alexandria University Faculty of Agriculture Sababasha, Alexandria, Egypt
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Background: Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in monolignol biosynthesis and plays critical roles in lignin-mediated plant defense against pathogens. Despite soybean global agricultural importance, systematic characterization of the CAD gene family and its role in disease resistance remains lacking. Methods: We performed comprehensive genome-wide identification, phylogenetic analysis, and expression profiling of soybean CAD genes. Haplotype diversity was assessed through whole-genome resequencing of 289 Chinese soybean accessions. Population genetic parameters (Fst, π, Tajima's D) were calculated to examine selection signatures. Functional validation was conducted through promoter activity assays, subcellular localization, and transgenic hairy root overexpression challenged with Fusarium oxysporum. Results: Seven GmCAD genes with conserved catalytic domains (PF00107, PF08240) were identified and grouped into four phylogenetic clusters. Expression profiling revealed strong pathogen-induced upregulation, with GmCAD3 showing the most dramatic response (8.64-fold induction at 14 days post-inoculation). Three major GmCAD3 haplotypes were identified based on seven SNPs (five promoter, two coding sequence). Haplotype 2 exhibited significantly enhanced disease resistance (disease severity index 72.4 ± 2.1) compared to Haplotype 1 (88.6 ± 1.8; P < 0.001), correlating with superior promoter activity. Population genetic analysis indicated maintenance of multiple functional haplotypes during domestication. Transgenic validation confirmed that GmCAD3 overexpression increases CAD enzyme activity (2-3 fold), lignin accumulation (70-88%), and pathogen resistance. Conclusions: This study provides the first comprehensive characterization of the soybean CAD gene family and demonstrates that GmCAD3 functions as a key regulator of lignin-mediated defense against F. oxysporum. Natural haplotype variation in GmCAD3 provides valuable molecular markers for breeding Fusarium-resistant soybean cultivars.
Keywords: Soybean, Cinnamyl alcohol dehydrogenase, Fusarium oxysporum, Genefunction characterization, haplotype analysis
Received: 24 Oct 2025; Accepted: 25 Nov 2025.
Copyright: © 2025 Zhou, You, Li, Li, Lamlom, Ren and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Honglei Ren
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