This Small Business Technology Transfer (STTR) Phase I proposes to develop a foundation for the production of rubber and high-value elastomers through the identification of the members of the elusive rubber transferase complex. The proposed novel research utilizes recently-developed biochemical separation protocols to concentrate membrane-bound rubber transferases several hundred-fold while simultaneously removing the rubber phase. Phase I of the project will focus on utilizing this technique to achieve the following specific aims: isolation of intact membrane-bound rubber transferase complexes from rubber particle membranes; characterization of bioactive lipids in rubber particle membranes; identification of rubber transferase proteins through a combination of proteomic and transcriptomic analysis; and expression of rubber transferase peptides in optimized heterologous systems. Data generated by this research will allow, for the first time, the purification and identification of members of the rubber transferase complex from membranes enriched in these proteins. Heterologous expression of these proteins paves the way for the construction of synthetic rubber production systems, and improvement of on-farm rubber crops. The broader impact/commercial potential of this project, if successful, is to enable the development of commercial rubber crops cultivated in the US. Over 93% of global natural rubber production is in Asia and relies on a single clonally-produced crop species (Hevea brasiliensis). The severe geographic restrictions for this crop are a major factor limiting natural rubber production. Current market models predict that, by the end of this decade, the world may experience a cumulative rubber shortfall of 6.6 million metric tons (US consumption is 1.2 MT/yr). This shortfall will have a dramatic negative impact on agricultural, civil, and military economic sectors. Rubber-producing plant species suitable for the US have been identified and are the focus of intensive commercial development and scientific research. This project will significantly increase the scientific understanding of rubber biosynthesis and speed the development and deployment of millions of acres of high yielding alternative rubber crops. It will enable the application of both molecular assisted breeding and biotechnological approaches to crop improvement and help create opportunities to introduce rubber production as a co-product of established crops. New rubber crops will create at least 5,000 new agribusiness jobs for every 50,000 acres, and self-sufficiency will require 2-4 million acres.
