Characterization of TaMYB Transcription Factor Genes Revealed Possible Early-Stage Selection for Heat Tolerance in Wheat

Wheat quality and quantity are challenged by increasing global temperature, which poses an urgent need for heat tolerance breeding in wheat. The identification of seedling-stage factors highly associated with reproductive-stage performance can enable early-stage selection and enhance the efficiency and effectiveness of breeding. This study investigated the myeloblastosis (MYB) gene family, one of the largest transcription factor (TF) gene families in plants, for its response to seedling- and reproductive-stage heat stress in wheat. Genome-wide analysis of MYB TF genes identified 876 TaMYB genes, and 48 genes were selected for qRT-PCR expression analysis based on in silico expression analysis under abiotic stresses. Correlation analysis of the quantitative real-time polymerase chain reaction (qRT-PCR) expression pattern of selected TaMYB genes in a heat-tolerant genotype (Perenjori) and two heat-sensitive genotypes (Brazil32 and Yitpi) at the seedling stage and grain-filling stage identified five TaMYB genes (TaMYB-327, TaMYB-049, TaMYB-030, TaMYB-226, and TaMYB-023) for the early-stage selection of heat tolerance and four TaMYB genes (TaMYB-232, TaMYB-343, TaMYB-305, and TaMYB399) for the early-stage selection of heat sensitivity in wheat. As important stress-responsive genes, these MYB genes showed similar expression patterns between early and late developmental stages, indicating the existence of a correlation for heat tolerance at the two stages, and therefore providing the theoretical basis for the early selection of heat tolerance in wheat.