Submitted to: Rubber World
Publication Type: Trade journal
Publication Acceptance Date: 6/30/2005
Publication Date: 11/1/2005
Citation: Cornish, K., McMahan, C.M., Pearson, C.H., Ray, D.T., Shintani, D.K. 2005. Domestic rubber producing crops. Rubber World. 233(2):40-44. Interpretive Summary: The United States is wholly dependent upon imports of natural rubber from tropical countries and is the world’s largest consumer of this strategic raw material. Synthetic polymers cannot match the high performance properties of natural rubber required for many applications and the best synthetics are prohibitively expensive. Also, protein contaminants in tropical natural products are responsible for the major public health problem of life-threatening Type I latex allergies estimated, by 1994, to affect as many as 20 million Americans. Domestic rubber crops will guarantee sufficient natural rubber to supply U.S. needs (> 2 million metric tons/year) and the multi-billion dollar health-related hypoallergenic rubber products market. The new, safe, sustainable domestic rubber industrial crops will enhance rural development and bring marginal farmlands back into profitable production.
Technical Abstract: Natural rubber is an irreplaceable raw material vital to industry, transportation, medicine and defense, largely produced from clonal plantations of Hevea brasiliensis in South-east Asia. Additional rubber-producing crops are greatly desired to increase biodiversity, protect supplies, and provide a safe alternative for people suffering from Type I latex protein allergy. Basic and applied research approaches were used to make the production of latex from Parthenium argentatum (guayule) a commercial reality. Also, similarities and differences in rubber biosynthesis among the evolutionarily divergent rubber-producing species, Hevea brasiliensis, Ficus elastica and P. argentatum have been characterized from biochemical and structural perspectives. Investigation of the contrasting roles of initiator, monomer and cofactor in the regulation of biosynthetic rate (a prime determinant of yield) and molecular weight (a prime determinant of quality) has revealed some unique features, which may prove useful to the biotechnological development of alternative rubber crops, such as sunflower, and improvement of existing ones, such as guayule. These classical biochemical approaches are now being supplemented by genomics and proteomics approaches, including reverse genetics in model systems, to functionally identify and exploit additional proteins and genes involved in rubber biosynthesis.