High levels of free amino acids (AAs) in tea leaves are crucial for tea flavor and health function, however, the dynamic AA biosynthesis, transport and turnover in tea plants remain elusive. Here we dissected whole tea plants for these dynamics by assessing AA profiles and transcriptomes of metabolic pathway genes in tea roots, stems, and leaves and revealing their distinctive features with regard to AA synthesis, transport, and degradation/recycling. Nitrogen assimilation dominated in the roots wherein glutamine (Gln), theanine, and Arginine (Arg) were actively synthesized. Arg was transporte...