CLONING AND CHARACTERIZATION OF CDNA-ENCODING FARNESYL DIPHOSPHATE SYNTHASE FROM RUBBER TREE (HEVEA-BRASILIENSIS)

Commercially used natural rubber (cis-1,4-polyisoprene) is a secondary metabolite of the rubber tree (Hevea brasiliensis). Previous studies have shown the involvement of a prenyl transferase in the final steps of natural rubber biosynthesis which includes polymerization of isopen tenyl pyrophosphate into rubber. Using synthetic oligonucleotides corr esponding to the partial amino acid sequences of this protein as probe s to screen a laticifer-specific cDNA library, we have isolated a full -length cDNA which encodes a 47 kDa protein with strong homology to fa rnesyl diphosphate synthases from many species. The catalytic activity of this protein was confirmed by complementing the deletion yeast mut ant. In Hevea, this gene is expressed in latex producing cells and in the epidermal region of the rubber plant suggesting a dual role for th e protein in the biosyntheses of rubber and other isoprenoids. Althoug h the expression level of this gene is not significantly affected by h ormone treatment (e.g. ethylene), regeneration of latex due to tapping increases its expression level.