Metabolomic profiling of in vitro and in situ grown Nilgiris tea reveals unique signatures for breeding decaffeinated varieties

This study was begun by establishing an in vitro culture in UPASI 9, a Nilgiris tea clone (Camellia sinensis) by optimising various factors. Anatomical studies demonstrated that use of lower carbendazim concentration for sterilisation (0.2%) produced viable and healthy explants for callus initiation. To confirm the genetic consistency of the regenerated plants, gene-specific SSR markers were developed and utilised. GC-MS was employed to analyse volatile metabolites extracted from callus, stem, micro shoots, and leaves of the UPASI 9 tea genotype. The results revealed distinct compositions of metabolites in each sample. More interestingly, caffeine was exclusively detected in leaf samples but absent in all other investigated tissues, despite the presence of Tea Caffeine Synthase (TCS) gene-specific SSRs. Thus, this study provided unique information on the absence of caffeine in in vitro grown Nilgiris tea clone, UPASI 9, as decaffeinated tea has a unique niche in the global market.