Monoterpenes in the glandular trichomes of tomato are synthesized from a neryl diphosphate precursor rather than geranyl diphosphate

INES SCHAUVINHOLD (ABATEDAGA), ANTHONY SCHILMILLER, VASILIKI FALARA, ROBERT L. LAST AND ERAN PICHERSKY.

Waterville Valley, NH, EE.UU.

Conferencia; Plant Metabolic Engineering; 2009

Gordon Research Conferences

A cis-prenyltransferase gene, neryl diphosphate synthase 1 (NDPS1), was identified in cultivated tomato (Solanum lycopersicum) cv M82 and in Solanum pennellii (a wild tomato relative). NDPS1 is expressed in type VI glandular trichomes of both species and encodes an enzyme that catalyzes the formation of neryl diphosphate (NPP) from isopentenyl diphosphate and dimethylallyl diphosphate. mRNA for a terpene synthase gene, phellandrene synthase 1 (PHS1), was also identified in the glands of both species. The two proteins are not identical but share a 94% amino acid identity. S. lycopersicon PHS1 encodes an enzyme that uses NPP to produce β-phellandrene as the major product, as well as a variety of other monoterpenes, while S. pennellii PHS1, uses the same substrate to produce α-phellandrene as major product. The profile of monoterpenes produced by both PHS1 enzymes is identical with the monoterpenes found in type VI glands of each species. PHS1 and NDPS1 map to chromosome 8, and the presence of a segment of chromosome 8 derived from S. pennellii LA0716 causes conversion from the M82 gland monoterpene pattern to that characteristic of LA0716 plants. The data indicate that, contrary to the textbook view of geranyl diphosphate as the ‘‘universal’’ substrate of monoterpene synthases, in tomato glands neryl diphosphate serves as a precursor for the synthesis of monoterpenes. The identification of novel reactions in such well-studied specialized metabolic pathways indicates that there is still much to be learned about the diversity in plant biochemical pathways.