Multi-Omics Analysis Reveals the Regulation of Amino Acid Biosynthesis in Cyclocarya paliurus Leaves Under Salt Stress

Amino acids are essential for plant growth and stress adaptation, and they exhibit distinct patterns under salt stress. However, the biosynthesis and accumulation of amino acids in <i>C. paliurus</i> under salt stress have not been fully studied. This research integrated metabolomics and transcriptomics data from <i>C. paliurus</i> leaves sampled at four salt concentrations and two sampling times to reveal the mechanisms underlying amino acid metabolism in response to salt stress. Principal component analysis revealed an environmental dependence in the amino acid accumulation patterns, with significant differences in amino acid content observed between samples treated with different salt concentrations and at different time points. Weighted gene correlation network analysis (WGCNA) identified key modules related to amino acid metabolism, with threonine synthase being upregulated under salt stress. Additionally, amino acids, such as proline, which function as osmolytes are increasing. The overexpression of structural genes in the phenylpropanoid biosynthesis pathway and genes encoding phenylalanine ammonia lyase was closely associated with amino acid accumulation, a process regulated by multiple transcription factors. These findings elucidate amino acid-mediated molecular responses to salinity and offer practical guidance for establishing <i>C. paliurus</i> plantations in southeastern coastal beach-lands of China.