Development of Crops to Produce Industrially Useful Natural Rubber

Abstract

Natural rubber, cis-1,4-polyisoprene, is an essential industrial commodity that most developed countries have to import. Hevea brasiliensis (Hevea), grown in tropical and subtropical areas, is the primary source of natural rubber. The high quality and quantity of the rubber cause us to focus on understanding rubber production in Hevea and two temperate plant species, guayule (Parthenium argentatum) and Russian dandelion (Taraxacum kok-saghyz). We review the cell biology, physiology, and biochemistry of rubber production in these three species. Rubber is synthesized on subcellular vesicles called rubber particles. Purified rubber particles alone contain all necessary factors for rubber production. We have used genomic approaches to identify expressed genes associated with rubber-producing tissues and proteomics to identify proteins associated with rubber particles. The protein and EST identifications guided our analysis of key proteins in rubber production, including cis-prenyltransferase, rubber elongation factor, small rubber particle protein, allene oxide synthase, HMG-CoA reductase, and allylic diphosphate synthases. We discuss biotechnological approaches to improve rubber production.