LOX-A4 shapes Triticum urartu gene pools and contributions to the A subgenome of polyploid wheat.

Li, Bei; Wang, Zhiyong; Dong, Lingli; Dong, Zhenying; Zhang, Kunpu; Wang, Yanpeng; Mir, Reyazul Rouf; Chu, Jinfang et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Lipoxygenases (LOXs) play vital roles in plant growth and defense. In this study, through genomic and molecular analyses, we discover a major LOX gene (LOX-A4) differentially expressed in Triticum urartu (Tu), the diploid progenitor of A subgenome in polyploid wheat. Compared to Tu accessions carrying wild type gene (LOX-A4<sup>W</sup>), those bearing mutant allele (LOX-A4<sup>m</sup>) show better growth but lower stress tolerance. These differences concur with a wider geographical distribution of LOX-A4<sup>m</sup> accessions than LOX-A4<sup>W</sup> materials in the Fertile Crescent. Interestingly, only mutant LOX-A4 alleles are detected in 3,516 worldwide tetraploid and hexaploid wheat lines; restoring LOX-A4<sup>W</sup> expression in common wheat inhibits growth but enhances stress tolerance. Furthermore, genome-wide identity-by-state analysis reveals that polyploid wheat A subgenome is more related to the A genome in 13 LOX-A4<sup>m</sup> Tu accessions. Thus, our work provides evidence that LOX gene variation shapes plant gene pools and their contributions to polyploid genome formation via regulating growth-defense trade-offs.