Identification of key genes contributing to amino acid biosynthesis in Torreya grandis using transcriptome and metabolome analysis

Torreya grandis has high economic and nutritional value due to the high nutrients in its kernels. The kernels of different development stages vary enormously in their amino acids content. However, the molecular basis and the regulatory mechanism of amino acid biosynthesis remain unclear. Here, transcriptome and metabolome analysis were performed. Correlation analysis result showed that 4 unigenes were significantly and positively correlated with at least 10 amino acids. The full length CDS of 2 unigenes (TgDAHP2 and TgASA1) were successfully cloned from the 4 unigenes for DAHP, ASA and CITS. Subcelluar localization analysis showed that both TgDAHP2 and TgASA1 were localized to the chloroplast. Overexpression of TgDAHP2 and TgASA1 in Arabidopsis can greatly increase the content of most amino acids. Moreover, 3 transcription factors were found to positively regulate the expression of TgASA1. This research contributes to understand the molecular regulatory mechanisms of amino acid biosynthesis in T. grandis.