Co‐expression network analysis of diverse wheat landraces reveals markers of early thermotolerance and a candidate master regulator of thermotolerance genes.

SUMMARY: Triticum aestivum L. (bread wheat) is a crop relied upon by billions of people around the world, as a major source of both income and calories. Rising global temperatures, however, pose a genuine threat to the livelihood of these people, as wheat growth and yields are extremely vulnerable to damage by heat stress. Here we present the YoGI wheat landrace panel, comprising 342 accessions that show remarkable phenotypic and genetic diversity thanks to their adaptation to different climates. We quantified the abundance of 110 790 transcripts from the panel and used these data to conduct weighted co‐expression network analysis and to identify hub genes in modules associated with abiotic stress tolerance. We found that the expression of three hub genes, all heat‐shock proteins (HSPs), were significantly correlated with early thermotolerance in a validation panel of landraces. These hub genes belong to the same module, with one (TraesCS4D01G207500.1) being a candidate master‐regulator potentially controlling the expression of the other two hub genes, as well as a suite of other HSPs and heat‐stress transcription factors (HSFs). In this work, therefore, we identify three validated hub genes, the expression of which can serve as markers of thermotolerance during early development, and suggest that TraesCS4D01G207500.1 is a potential master regulator of HSP and HSF expression – presenting the YoGI landrace panel as an invaluable tool for breeders wishing to determine and introduce novel alleles into modern varieties, for the production of climate‐resilient crops. Significance Statement: Global wheat yields and crop growth are vulnerable to damage by heat stress, a threat that is likely to become more common globally in the coming years through climate change. Conducting weighted co‐expression network analysis on 337 diverse landrace accessions, we identified and validated TraesCS4D01G207500.1 as a hub gene that can be used as a marker of early thermotolerance, seemingly via the regulation of the expression of a suite of HSP and HSF genes. [ABSTRACT FROM AUTHOR]