Worldwide Selection Footprints for Drought and Heat in Bread Wheat (Triticum aestivum L.)

Plants (Basel). 2022 Sep 1;11(17):2289. doi: 10.3390/plants11172289.

Abstract

Genome-environment Associations (GEA) or Environmental Genome-Wide Association scans (EnvGWAS) have been poorly applied for studying the genomics of adaptive traits in bread wheat landraces (Triticum aestivum L.). We analyzed 990 landraces and seven climatic variables (mean temperature, maximum temperature, precipitation, precipitation seasonality, heat index of mean temperature, heat index of maximum temperature, and drought index) in GEA using the FarmCPU approach with GAPIT. Historical temperature and precipitation values were obtained as monthly averages from 1970 to 2000. Based on 26,064 high-quality SNP loci, landraces were classified into ten subpopulations exhibiting high genetic differentiation. The GEA identified 59 SNPs and nearly 89 protein-encoding genes involved in the response processes to abiotic stress. Genes related to biosynthesis and signaling are mainly mediated by auxins, abscisic acid (ABA), ethylene (ET), salicylic acid (SA), and jasmonates (JA), which are known to operate together in modulation responses to heat stress and drought in plants. In addition, we identified some proteins associated with the response and tolerance to stress by high temperatures, water deficit, and cell wall functions. The results provide candidate regions for selection aimed to improve drought and heat tolerance in bread wheat and provide insights into the genetic mechanisms involved in adaptation to extreme environments.

Keywords: Genome–environment Associations (GEA); Triticum aestivum L.; adaptation; drought stress; heat stress; landraces.

Grants and funding

This work was implemented by CIMMYT as part of the Seeds of Discovery (SeeD) Initiative in collaboration with Universidad Autónoma Agraria Antonio Narro (UAAAN), made possible by the generous support of Sustainable Modernization of Traditional Agriculture (MasAgro) Project funded by the Ministry of Agriculture, and Rural Development (SADER) of the Government of Mexico. Any opinions, findings, conclusion, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of SADER.