Understanding Darjeeling tea flavour on a molecular basis.

ABSTRACT

Darjeeling teas are the highest grown teas in the world and preferred for its flavour, aroma and quality. Apart from the genetic makeup of the plant, earlier reports suggest that insect infestation, particularly jassids and thrips triggers the aroma and flavour formation in Darjeeling tea. The present work encompasses the identification of the genes/transcriptomes responsible for the typical flavour of Darjeeling tea, besides understanding the role of jassids and thrips in particular, in producing the best cup character and quality. The quantitative real time PCR analysis was based on a suppression subtractive hybridisation forward library of B157 (tea clone infested with thrips), providing us transcripts related to aroma and flavour formation. We observed the expression of genes like leucine zipper, ntd, nced, geraniol synthase, raffinose synthase, trehalose synthase, amylase, farnesyl transferase, catalase, methyl transferase, linalool synthase, peroxidases, elicitor responsive proteins, linamarase, nerolidol linalool synthase 2, 12-oxophytodienoate reductase, glucosidase, MYB transcription factor, and alcohol dehydrogenase, highly regulated due to insect infestation, manufacturing stresses and mechanical injury. The first report on gene expression dynamics in thrips infested Darjeeling tea leaves can be extrapolated with increase in volatiles which is responsible for enhancing the quality of Darjeeling tea, specially the flavour and aroma of the infusion. We hope to model these responses in order to understand the molecular changes that occur during Darjeeling tea flavour formation.