Implementation of CsLIS/NES in linalool biosynthesis involves transcript splicing regulation in Camellia sinensis

Volatile terpenoids produced in tea plants (Camellia sinensis) are airborne signals interacting against other ecosystem members, but also pleasant odorants of tea products. Transcription regulation (including transcript processing) is pivotal for plant volatile terpenoid production. In this study, a terpene synthase gene CsLIS/NES was recovered from tea plants (C.sinensis cv. Long-Men Xiang). CsLIS/NES transcription regulation resulted in 2 splicing forms: CsLIS/NES-1 and CsLIS/NES-2 lacking a 305bp-fragment at N-terminus, both producing (E)-nerolidol and linalool in vitro. Transgenic tobacco studies and a gene-specific antisense oligo-deoxynucleotide suppression applied in tea leaves indicated that CsLIS/NES-1, localized in chloroplasts, acted as linalool synthase, whereas CsLIS/NES-2 localized in cytosol, functioned as a potential nerolidol synthase, but not linalool synthase. Expression patterns of the 2 transcript isoforms in tea were distinctly different and responded differentially to the application of stress signal molecule methyl jasmonate. Leaf expression of CsLIS/NES-1, but not CsLIS/NES-2, was significantly induced by methyl jasmonate. Our data indicated that distinct transcript splicing regulation patterns, together with subcellular compartmentation of CsLIS/NE-1 and CsLIS/NE-2 implemented the linalool biosynthesis regulation in tea plants in responding to endogenous and exogenous regulatory factors. Linalool and nerolidol produced in tea plants are not only airborne signals interacting against other ecosystem members for better plant fitness but also floral scent determinants of tea products. A better understanding of the mechanisms underlying their biosynthesis in tea plants may provide effective approaches for tea aroma quality and tea productivity improvement. In this study, tea CsLIS/NES gene was found being differentially involved in linalool and nerolidol biosynthesis due to its 2 splicing transcripts with distinct expression patterns. Regulation at transcription (including transcript processing) and subcellular compartmentation of the 2 CsLIS/NES transcripts implement the biosynthesis regulation of linalool and nerolidol in tea plants in responding to endogenous and exogenous regulatory factors.