Genome-wide identification of TGA transcription factors in wheat: Evolution, expression and verification

Abstract Background: The TGA transcription factors have been considered one of the essential gene families for the physiological process of plants, and they participate in plant defence by sensing and modulating reactive oxygen species. In contrast, the study about the function of TGA transcription factors in hexaploid wheat and its progenitors has not been conducted. Results: In this study, we identified 38, 12 and 26 TGA genes in hexaploid wheat and its two progenitors, respectively. The functional similarities between Arabidopsis thaliana, Oryza sativa, Triticum aestivum, T. dicoccoides and Aegilops tauschii were performed by the phylogenetic tree and classified into four groups. The chromosome location and the collinear pairs were relatively well conserved. Based on that, the gene structure and conserved motifs of the TaTGAs indicated a solid ability to integrate gene networks. The cis-element related to hormone and stress resistance was identified in the promoter region of TaTGAs. We retrieved the expression profile of TaTGAs' response to biotic stress. 12 TaTGAs with significant differential expression were confirmed by qRT-PCR. TaTGA13 was chosen for the function analysis as it was significantly differentially expressedafter stripe rust inoculation. We obtained the phenotype of the plants silenced by virus-induced gene silencing (VIGS) and mutation lines. Conclusions: The TGA gene family were identified in hexaploidy wheat and its two progenitors. These results suggest TGAs were relatively well conserved in Gramineae and play an essential role in wheat stripe rust resistance.