Use of Arabidopsis Transcription Factors to Increase Rubber Yield in Guayule

NON-TECHNICAL SUMMARY: Natural rubber is a vital and irreplaceable raw material. The United States uses approximately 20% of the global supply for its industries and is completely dependent on imports from developing countries. A dependable rubber supply is endangered by many factors, including susceptibility to pathogen attack, diminishing acreage as growers move toward higher value crops, increasing global demand for rubber, and changing political climates. Thailand, Indonesia and Malaysia formed the International Tripartite Rubber Corporation, cut production by 4% and exports by 10 % for 2003, and caused the price of natural rubber to increase almost 100 percent from a 30-year record low of $0.48 to $0.83 per kilogram. There are several incentives to develop a US-based supply of natural rubber (see Public Laws 95-592 and 98-284). The occurrence of "latex allergy" strengthens the need for development of alternative sources of natural rubber. U.S. natural rubber production will be needed in the future to supplement and replace the 55% market share currently enjoyed by petroleum derived synthetic rubbers. The purpose of this grant is to determine if transcription factors from Arabidopsis thaliana can positively impact rubber or resin yield. Using traditional breeding programs, the best lines of P. argentatum produce about 10% rubber dry weight. However, wild P. argentatum plants can contain 20% rubber, so this level can be attained and tolerated. Our goal, therefore, is to increase the rubber yield without compromising the quality of the rubber produced.