Genome-wide analysis of wheat Di19 gene family and functional analysis of TaDi19-7 in transgenic Arabidopsis

Di19 (Drought-induced 19) proteins play an important role in the regulation of plant growth and stress response. Although Di19 genes have been well-studied in plants, they have not been sufficiently investigated in wheat. Here, we identified 18 Di19 genes (TaDi19s) in wheat and categorized them into three groups using phylogenetic analyses compatible with gene exon-intron structures and protein motif compositions. Genome-wide duplication analysis of the Di19 gene family between wheat and other species showed that there were more duplication events that occurred between wheat and Brachypodium distachyon than Oryza sativa and Arabidopsis thaliana. Further cis-regulatory elements screening revealed that TaDi19 genes may be involved in plant development and stress response. Gene expression analysis revealed diverse expression patterns of TaDi19 genes in different tissue types and stress conditions. Moreover, TaDi19–7 overexpression promoted flowering and branching in transgenic Arabidopsis. Additionally, TaDi19–7 overexpressing lines were more sensitive to drought and salt stresses compared to wild-type plants. Finally, we found that TaDi19–7 affects flowering and abiotic stress response by binding and regulating the expression levels of FT, SOS2, and DREB2A in Arabidopsis. Overall, our study characterized the Di19 gene family in wheat and investigated the biological functions of TaDi19–7 in plant growth and stress tolerance, therefore providing a basis for functional study of TaDi19s in wheat development and abiotic stress response.