Characterization of the terpene synthase family in Solanum lycopersicum

VANESSA FALARA 1, ANTHONY SCHILMILLER 2, INES SCHAUVINHOLD (ABATEDAGA), ROBERT L. LAST 2, ERAN PICHERSKY

Banff, Alberta, Canada

Conferencia; Banff Conference on Plant Metabolism; 2010

University of Calgary

Monoterpenes (with 10 carbon backbone), sesquiterpenes (C15) and diterpenes (C20) are synthesized by a group of structurally and evolutionarily related enzymes called terpene synthases (TPSs). The C≤20 terpenes serve many ecological roles, including as floral scent attractants of pollinators, vegetative defense compounds, and aroma compounds in fruits. The genome of Arabidopsis thaliana contains 32 TPS genes, and the function of fewer than half has been determined. A detailed analysis of the roles of individual members of the TPS gene family in a crop plant has not yet been reported. Cultivated tomato (Solanum lycorpersicum) serves as an excellent plant model for the roles of terpenoids, which confer pest and pathogen resistance as well as fruit organoleptic characteristics. The tomato genome project has recently made available a set of “genomic scaffolds”, which has allowed us the identification of the terpene synthase gene family. We found at least 37 TPS genes, of which only 17 are represented by cDNA sequences in publicly available EST databases. Many of the TPS genes we identified are found in tandem repeats, sometimes accompanied by genes encoding other enzymes with potential roles in terpene biosynthesis. Expression profile of all 37 TPS genes in trichomes, leaves, stems, petioles, flowers, roots and fruits revealed expression of at least 24 genes, with tissue specificity or preferential expression observed for many. We have begun to correlate the pattern of expression of specific genes with the chemical profile of the corresponding tissues and to determine the in vitro biochemical activity of enzymes encoded by specific TPS genes. We are also comparing the genome organization and function of TPS genes in related species, to examine how terpene metabolism has evolved in the genus. Initial biochemical analysis has already indicated unusual features of some TPS enzymes, such as use of a non-canonical substrate.