Transcriptional regulation of volatile terpene biosynthesis in tomato type VI trichomes

Plants develop multiple strategies to defense themselves against biotic stresses. Glandular trichomes are metabolic cell factories with the capacity to synthesize, store and secrete large quantities of specialized metabolites. These specialized metabolites in glandular trichomes are chemically diverse and play essential roles in the interactions of plants with the surrounding environment, particularly in plant defense against herbivores. Cultivated tomato Solanum lycopersicum and its wild relatives have in total eight types of trichomes, among which type VI glandular trichomes mainly accumulate terpenoids, as well flavonoids. Terpenoids comprise the most diverse class of plant specialized metabolites, with volatile mono- and sesquiterpenes playing an important role in plant defense. This thesis established the dual roles of the basic helix-loop-helix (bHLH) transcription factor SlMYC1 in type VI trichome development and the regulation of volatile terpene biosynthesis in glandular cells. Comparative transcriptome analysis and metabolome analysis revealed the involvement of SlMYC1 in regulating the biosynthesis of volatile terpenes as well as other specialized metabolites especially flavonoids in tomato type VI trichomes. Further studies investigated the distinct roles of SlMYC1 and SlMYC2 in jasmonate (JA) signaling, and tomato defense against the spider mite Tetranychus urticae. Additionally, this thesis also focuses on the identification of other transcription factors relevant to the transcriptional regulatory network of volatile terpene biosynthesis in tomato type VI glandular trichomes.