Genome-wide identification of the GLK gene family in wheat (Triticum aestivum L.) and analysis of expression responses in different environments

Wheat plays a crucial role in ensuring global food security, and the GLK family of transcription factors is an important regulator of chloroplast development, chlorophyll synthesis, photosynthesis, and stress tolerance. However, there are few genome-wide studies of the GLK genes in wheat, especially regarding their roles in photosynthesis and phosphorus (Pi) deficiency. In this study, 173 GLK transcription factors (TFs) were identified in wheat and combined with bioinformatics analysis and statistical methods. The wheat GLK family was divided into eight subfamilies (I-VIII) based on phylogenetic relationships and motif composition. The TaGLK genes had mainly undergone segmental duplication during their evolution and had been subjected to strong selective pressure for purification. Both subcellular localization predictions and experimental results suggest that the wheat GLK protein was primarily localized in the cell nucleus. The TaGLK genes showed a higher degree of collinearity with those of maize in the gramineous family, suggesting that the two were more closely related in terms of their evolutionary relationship. Transcriptome data analysis results indicated that the expression patterns of wheat GLK genes were significantly different in various tissues, and there were significant differences in the amount of expression. Meanwhile, RT-qPCR analysis revealed that TaGLKs genes expression were induced by light, dark, Pi starvation, and drought stress. Among them, members of subfamily VI were structurally conserved and may be involved in the development of chloroplasts and may positively regulate photosynthesis and chlorophyll biosynthesis, whereas members of subfamily VIII had a conserved motif (LHEQLE) and may be involved in the stress response to phosphorus deficiency. These findings provide valuable information for further studies on the function of TaGLK genes and their potential roles in light signal sensing, chloroplast development, and abiotic stress response.