Functional Framework of Amino Acid Transporters in Quinoa: Genome-Wide Survey, Homology, and Stress Response

Abstract

The role of amino acid transporter (AAT) genes in facilitating the transmembrane movement of amino acids between cells and various cellular components has been characterized in several plant species. Quinoa (Chenopodium quinoa Willd.), a renowned nutritious crop known for its amino acid composition, has not yet had its AAT genes characterized. Therefore, the identification and characterization of AAT genes in quinoa will help bridge this knowledge gap and offer valuable insights into the genetic mechanisms underlying amino acid transport and metabolism. This study focuses on gene expression, gene structure, duplication events, and a comparison of functions studied to establish the role of AAT genes. A total of 160 non-redundant AAT genes were identified in quinoa and classified into 12 subfamilies, with 8 subfamilies belonging to the amino acid/auxin permease (AAAP) family and 4 to the amino acid-polyamine-organocation (APC) superfamily family. The chromosomal localization, gene structures, and conserved motifs of these genes were systematically analyzed. Expression profiling revealed diverse expression patterns across various tissues and in response to drought and salt stresses. Segmental and tandem duplications were found to contribute to the gene duplication and expansion of the CqAAT gene family. Additionally, CqCAT6 and CqAAP1 were predicted to regulate the long-distance transportation and distribution of amino acids, making them potential candidate genes for further research. Overall, this information could serve as a foundation for the identification and utilization of CqAATs in Quinoa, enhancing our understanding of amino acid transport mechanisms in this important crop.