Integrative transcriptomic and functional analyses identify TaARF in the auxin response pathway as a hub gene...

Heat stress severely impacts the growth, development, and yield of wheat (Triticum aestivum L.) throughout its lifecycle. Identifying key genes regulating heat tolerance is crucial for breeding climate-resilient wheat cultivars. In this study, Zhenongmai 1 (ZNM1), a heat-tolerant wheat cultivar from Zhejiang Province, exhibited a significantly higher seedling survival rate than the heat-sensitive Yangmai 20 after heat stress. At the maturity stage, ZNM1 maintained superior grain yield components under heat stress, retaining 90.05% of its thousand-grain weight (TGW), while YM20 only retained 84.53%. To elucidate the molecular regulatory mechanism underlying heat tolerance in ZNM1, Weighted Gene Co-expression Network Analysis (WGCNA), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, were performed to screen heat stress-responsive candidate genes. The results revealed that these candidate genes were predominantly enriched in biological processes including auxin metabolism and NAD(P)H dehydrogenase complex assembly, which are critical for wheat heat tolerance regulation. The expression patterns of 11 core candidate genes were verified by quantitative real-time PCR (RT-qPCR), validating the credibility of the transcriptomic data. Heterologous yeast expression assays further confirmed that TaARF positively regulated plant heat tolerance. Additionally, we systematically analyzed the haplotype variations of TaARF among wheat germplasms from different geographical environments and characterized its tissue-specific expression profiles. This study clarifies the key genes and potential molecular pathways associated with wheat heat tolerance, providing valuable gene resources and theoretical references for the genetic improvement of heat-resistant wheat varieties.