Genome-wide identification and light-regulated analysis of the amino acid transporter gene family in lettuce

The amino acid transporter (AAT) gene family encodes a group of membrane proteins in plants that mediate amino acid transport, regulate nitrogen allocation, and contribute to stress adaptation. In this study, a total of 102 LsAATs were identified in lettuce. They were classified into 12 subfamilies and distributed across all the chromosomes. Forty percent of them were expanded via gene duplication, and 23 and 18 LsAATs were segmentally and tandemly duplicated, respectively. Considerable variations in physicochemical properties, conserved motifs, and cis-acting elements were observed among these genes. The LsAATs and phenolic compounds regulated by continuous lighting and light quality were analyzed. Furthermore, three-dimensional structural models of light-regulated LsAATs were constructed and subsequently aligned with characterized homologs in other species. The results suggested that several light-regulated LsAATs might be involved in quality changes, nutrient uptake, long-distance transport, and stress adaptation. Overall, LsAATs are evolutionarily stable in plants and diverse in terms of their physicochemical properties and potential molecular biology.