Molecular Genetic Analysis of Natural Rubber Biosynthesis

Natural rubber (cis-1,4-polyisoprene) is an irreplaceable starting material for thousands of products, many of which are absolutely essential, in particular for modern medicine. Rubber is found in the latex of an aqueous emulsion contained in the specialized structures of rubber-producing plants, laticifers. More than 2500 plant species are capable of synthesizing natural rubber. However, Hevea brasiliensis (Brazilian rubber tree, Hevea) is currently the only commercially important species producing raw material for rubber production. Several proteins play key roles in the biosynthesis of natural rubber. Cis-prenyltransferases, activators of cis-prenyltransferases, and small proteins associated with rubber particles are among them. These proteins are directly involved in the synthesis of the polyisoprene chain. In this review, the molecular genetic aspects of the functioning of these proteins in the biosynthesis of natural rubber are analyzed. In particular, the cloning, expression, and functional analysis of cis-prenyltransferase coding genes from Arabidopsis thaliana, Hevea brasiliensis, and Taraxacum kok-saghyz are described, and the role of small proteins associated with rubber particles in the biosynthesis of natural rubber are investigated. Special attention is paid to the analysis of the effect of the expression level of the cis-prenyltransferase coding genes and the cis-prenyltransferase activator coding gene on the production of natural rubber in plant cells.