yinhuayan@qau.edu.cn

Alanine glyoxylate aminotransferase (AGT) is an important member of the Alanine aminotransferase (AlaAT) family, which plays an important role in plant photorespiration. Photorespiration is an important source of H2O2 in plant cells and an important component of cell REDOX maintenance, which affects plant response to abiotic stresses such as drought, high temperature and high salt. Wheat (Triticum aestivum L.) is one of the three major food crops in the world.

In actual production, abiotic stress such as drought seriously affects the formation of wheat yield and quality, and then causes huge economic losses. Therefore, the analysis of the expression of alanine-glyoxylate aminotransferase gene under drought stress and its molecular mechanism in response to drought stress is of great significance for the breeding of new wheat varieties resistant to drought.

In this study, the differentially expressed gene TaAGT2-1A was screened based on the transcriptomic expression profile of Qingmai 6 under drought stress, and its basic physicochemical properties, gene expression characteristics, phylogenetic relationship, gene function and drought resistance regulation pathway were analyzed.

The results showed that the full-length cDNA of TaAGT2-1A was 1434 bp, encoding 477 amino acids (C2288H3601N633O665S18), molecular weight was 51.2 KDa, and theoretical isoelectric point (pI) was 8.13. TMHMM and SignalP online prediction showed that the protein encoded by TaAGT2-1A gene had no transmembrane region and no signal peptide, so it was inferred that the protein encoded by TaAGT2-1A gene was not secreted protein.

Under drought stress, compared with wild type, TaAGT2-1A overexpressed transgenic wheat had increased germination potential (1.92 times), POD (1.65 times), soluble sugar content (1.85 times), root length and effective tillering (2.5 times) at germination stage, and POD (1.65 times) at seedling stage.

The results indicated that overexpression of TaAGT2-1A could significantly improve drought resistance of wheat. PlantRegmap and transcriptomic data were used to screen the transcription factor TaDREB4A that may bind to the promoter of TaAGT2-1A, and the results of yeast single hybridization and EMSA tests proved that the two could bind. This study lays a foundation for further research on the regulatory mechanism of drought resistance gene TaAGT2-1A.