Glandular trichomes: More light - more terpenoids.
Glandular trichomes on the leaf surface of various plants produce some important secondary metabolites in large amounts, which makes them attractive as metabolic cell factories. According to a model proposed by IPB scientists in 2017 (Balcke et al.), certain trichomes generate most of the energy needed for their extraordinary secondary metabolite production from photosynthesis, due to the presence of chloroplasts and functioning photosynthetic systems. Nevertheless, it is still not fully understood how primary metabolism from photosynthesis affects secondary metabolism of glandular trichomes.
In collaboration with partners from Düsseldorf and Aachen, IPB scientists have now reconstructed the metabolism in the photosynthetically active glandular trichome type VI of a Solanum lycopersicon cultivar. Using previously published transcriptome and metabolome data and based on the model proposed by Balcke et al., the trichome experts simulated the effects of photosynthetic activity on the trichomes' metabolic productivity. In the simulation, they observed an increase in trichomal terpenoid production with increasing light intensity. In addition, the scientists predicted the production of specific terpene classes under different light conditions.
In a subsequent step, the scientists confirmed their mathematical predictions experimentally. They demonstrated a significant increase in the biosynthesis of monoterpenes in particular, while sesquiterpene production remained unchanged at higher light intensity. Due to the increased energy level, the scientists explained, carbon atoms are more likely used in assimilating, i.e. biosynthetic, processes than in catabolic, degrading reactions. In the future, the results of this work can be used to guide the design of new experiments aimed at modulating terpenoid production.
