A new route for monoterpene biosynthesis in tomato glandular trichomes: the use of neryl diphosphate rather than geranyl diphosphate as substrate

SCHILMILLER, ANTHONY L (A) SCHAUVINHOLD (ABATEDAGA), INES, CHARBONNEAU, AMANDA, LAST, ROBERT L, PICHERSKY, ERAN

Honolulu, Hawaii, EE.UU.

Conferencia; Plant Biology Conference; 2009

Amer. Asoci.Plant Biologists

Trichomes are epidermal protuberances present on aerial tissues of many plants and are capable of producing an array of specialized metabolites having a wide range of known and proposed functions including coping with biotic and abiotic stresses and as attractants for pollinators and seed-dispersing animals. Many of these specialized metabolites also have significant commercial value for use as pharmaceuticals or cosmetic fragrances. We are using tomato trichomes to study the natural products these distinctive epidermal cells produce. From sequencing of a tomato (Solanum lycopersicum cv. M82) trichome cDNA library, we recently identified putative cis-prenyltransferase and terpene synthase genes that map to chromosome 8. Chromosomal substitution lines containing DNA from S. pennellii LA0716 at this region of chromosome 8 produced a monoterpene profile characteristic of LA0716 indicating these genes could encode proteins that catalyze the production of monoterpenes in tomato trichomes. The cis-prenyltransferase gene was shown to encode Neryl Diphosphate Synthase 1, an enzyme that produces neryl diphosphate (NPP) from isopentenyl diphosphate and dimethylallyl diphosphate. We also show that NPP is the substrate for the terpene synthase (β-Phellandrene Synthase 1) which produces β-phellandrene as the major product as well as several other monoterpenes. Recombinant PHS1 from M82 produced in vitro a monoterpene profile identical to that found in Type VI glands of M82 plants. The data indicate that in tomato glands, NPP is the precursor used for the synthesis of monoterpenes by PHS1, and not geranyl diphosphate (GPP), which was previously suggested to be the universal substrate of monoterpene synthases.