Exploration of Heat Stress-Responsive Markers in Understanding Trait Associations in Wheat

Abstract

Heat stress (HS) is detrimental to wheat production and productivity globally. To combat HS, several genetic, molecular, and genomic approaches have been employed in the past. Analyzing the physiochemical mechanisms and the important regulatory genes involved is the key to develop HS tolerant plants. In the present work, a total of 243 novel simple sequence repeat (SSR) markers developed from stress-associated genes identified through RNA-seq were used for understanding marker–trait associations. 37 SSRs were found to be clearly polymorphic and among these, 28 SSR loci were significantly associated with component traits of HS tolerance. The polymorphic SSRs were validated for diversity analysis on a subset of 85 genotypes. The genotypes were grouped into four clusters representing diverse and similar alleles imparting HS tolerance in Indian and exotic genotypes. Additionally, 28 genes selected for the expression analysis confirmed that 15 genes were induced under HS in the thermotolerant WH1021 and Raj3765 and repressed in thermosusceptible HD2009 cultivar. Hence, the information on traits associated with candidate genes and the SSR markers overlying on the gene will enhance our understanding of thermotolerance mechanism operating in wheat and will help the breeders in the precise development of heat-tolerant genotypes through marker-assisted selection (MAS).