Genome-wide investigation of heat shock transcription factor family in wheat (Triticum aestivum L.)

Abstract

Background: Heat shock transcription factors (HSFs) play crucial roles in resisting heat stress and regulating plant development. Investigating the HSF family is essential for understanding the fertility conversion mechanism in thermo-sensitive male sterile wheat. Previous studies have investigated the HSF family in wheat but it is necessary to conduct more in-depth and systematic analyses based on the newly published reference genome. Results: In the present study, 61 wheat Hsf (TaHsf) genes were identified using two main strategies and renamed based on their physical locations on chromosomes. According to the gene structure and phylogenetic analyses, the 61 TaHsf genes were classified into three categories and eleven subclasses. The genes were unequally distributed on 21 chromosomes, including two pairs of tandem duplication genes and 52 TaHsf segmental duplication genes. According to the cis-elements identified, most of the TaHsfs can be activated by Ca++ and MYB, and they respond to drought, light, copper, and other stresses as well as heat shock. RNA-seq analysis indicated that the A2 class TaHsf genes exhibited persistently upregulated expression levels in the leaves/shoots, roots (except in the vegetative growth and reproductive growth stages), spikes, and grains in wheat under normal conditions. The A and B class TaHsf genes were positively regulated during the resistance to heat, whereas the C class genes were involved in drought regulation in wheat. Only the A and B class TaHsf genes were upregulated under fertile conditions in thermo-sensitive male sterile wheat. Conclusion: In this study, 61 wheat Hsf genes were identified based on the complete wheat reference genome. This comprehensive analysis provides novel insights into the TaHsf genes, including their diverse functions and involvement in metabolic pathways.