Project Number: 5325-21410-020-00
Project Type: Appropriated

Start Date: Oct 01, 2010
End Date: Sep 30, 2015

Objective:
The overall objective of the proposed research is to develop improved plant germplasm and advanced process technology enabling domestic production of two strategic industrial raw materials – domestic natural rubber and castor oil, along with their valuable co-products. The crops for industrial production of rubber are Parthenium argentatum (guayule), Taraxacum kok-saghyz (Russian dandelion) and Hevea brasiliensis (Hevea), and for castor oil are Ricinus communis (castor) and Lesquerella fendleri (Lesquerella). Domestic production of both castor and rubber has taken place in the past, yet critical issues denied sustainability of these important industrial crops. We propose to address these via the following objectives: Objective 1: Develop germplasm that enables domestic commercial production of natural rubber and ricinoleate by metabolic engineering and conventional breeding. Objective 2: Develop technologies to enable the domestic production of natural rubber and ricinoleate with properties as good as or better than existing sources for industrial applications. Identify chemical processes and/or modifications to develop superior performance properties of natural rubber from domestic sources. Identify processing methods to enhance the value of castor oil byproducts.

Approach:
Improvements in natural rubber yield will be sought through genetic manipulation of guayule and Russian dandelion plants. The biosynthesis of ricinoleate in Lesquerella will be metabolically engineered. Transformation methods will be developed and optimized; efficacious high expression and tissue-specific promoters will be identified. Genetically altered lines will be phenotypically characterized for alterations in enzymatic activity and production of target metabolites. Promising lines will be tested in controlled environment greenhouse and/or field trials on site or at collaborator locations. Improved germplasm will also be developed/identified through characterization of NPGS castor and Russian dandelion lines. Mutagenesis will be used to develop high yield, low toxin and allergen castor lines. More specific knowledge of the biosynthetic pathways for production of natural rubber and hydroxy fatty acids will be achieved through physiological, cell biology, and biochemical studies. Knowledge of the detailed physical and chemical characteristics of natural rubber from alternative crops will be developed to elucidate the mechanisms for differences from incumbent materials and to provide strategies for technological equivalence. The processing of castor seed meal by bioconversion to reduce toxin and allergen content of byproducts will be researched.