Background: Amino acid transporters (AATs), which transport amino acids across cellular membranes, play important roles in alleviating plant damage under stresses as well as in plant growth and development. Although this family has been systematically studied in many plant species, little is known about the AAT genes in bread wheat ( Triticum aestivum L.) due to its complex genome sequence.
Results: In this study, a total of 296 AAT genes were identified from the latest wheat genome sequence (IWGSC v1.1) and classified into twelve distinct subfamilies based upon their sequence composition and phylogenetic relationship. Wheat AAT family members showed significant heterogeneity in chromosome distribution, with relatively high density in specific chromosomal regions. Comparison the number variation of gene copies and transmembrane regions of AAT genes in different sub-genome showed that the functional adaptation of the wheat AAT family during wheat polyploidization was driven mainly by sequence mutations rather than copy number variation. In addition, it was confirmed that changes in gene structure and protein conserved domains played important roles in the functional differentiation of the AAT family. Finally, the expression profiles of these TaAAT genes under heat, drought and salt stress and in the development stage of wheat showed that the expression of TaAATs exhibited abundant and distinct expression patterns under different abiotic stresses or in different tissues, and several important candidate AAT genes that may affect abiotic stress response and grain quality were also identified.
Conclusions : In this study, a total of 297 AAT proteins were systematically identified and characterized. Our study highlighted the important roles of gene duplication events in the expansion and functional differentiation of the wheat AAT family. The expression profiles of TaAATs revealed their importance for the grain development of wheat and their response to biotic and abiotic stresses. Our study also provided a theoretical basis for the further functional identification and utilization of the AAT gene family in wheat or other crops.