Genome-Wide Identification, Phylogeny and Expression Analysis of Subtilisin (SBT) Gene Family under Wheat Biotic and Abiotic Stress

The subtilisin-like protease (SBT) family is widely known for its role in stress resistance to a number of stressors in different plant species, but is rarely studied in wheat. Subtilisin-like serine proteases (SBTs) are serine proteolytic enzymes that hydrolyze proteins into small peptides, which bind to receptors as signal molecules or ligands and participate in signal transduction. In this study, we identified 255 putative SBT genes from the wheat reference genome and then divided these into seven clades. Subsequently, we performed syntenic relation analysis, exon-intron organization, motif composition, and cis-element analysis. Further, expression analysis based on RNA-seq and tissue-specific expression patterns revealed that TaSBT gene family expression has multiple intrinsic functions during various abiotic and biotic stresses. Analysis of RNA-seq expression assays and further validation through qRT PCR suggested that some of the TaSBT genes have significant changes in expression levels during Pst interaction. TaSBT7, TaSBT26, TaSBT102, and TaSBT193 genes showed increasing expression levels during compatible and non-compatible interactions, while the expression levels of TaSBT111 and TaSBT213 showed a decreasing trend, indicating that these members of the wheat SBT gene family may have a role in wheat’s defense against pathogens. In conclusion, these results expand our understanding of the SBT gene family, and provide a valuable reference for future research on the stress resistance function and comprehensive data of wheat SBT members.