Biosynthesis of theanine (γ-ethylamino-l-glutamic acid) in seedlings of Camellia sinensis

Theanine is a major amino acid in young tea seedlings. It is synthesised from [15N]glutamic acid, [15N]alanine and [14C]ethylamine in all parts of tea seedlings. Conversion of exogenously supplied (15NH4)2SO4 is utilised in theanine synthesis mainly in roots. Expression of theanine synthesis genes was observed in shoots and roots.