Engineering Enzymatic Redirection of Natural Crop Oil Production to Industrial Oil Production
Commodity Utilization Research
Project Number: 6435-41000-106-00
Start Date: Aug 16, 2010
End Date: Aug 15, 2015
The overall objective of this project is to define the minimal sets of genes required for efficient synthesis and accumulation of industrially important fatty acids in transgenic hosts, and to express these genes in microbes and commodity oilseed crops for production of value-added industrial oils. During the project, we will focus on the following objectives:
Objective 1: Use model plant systems to identify and refine transgenic expression conditions for critical industrial oil biosynthetic genes.
Objective 2: Identify substrate specificity-determining sequences in pertinent genes from tung tree related species.
Objective 3: Engineer yeast strains for use in microbial bioconversion system.
Objective 4: Transfer knowledge of minimal necessary gene sets from current research (on tung tree genes) to other novel oilseed whose oil represents greater market size or strategic value; i.e., epoxy (from Crepis, Vernonia, and Euphorbia species) or acetylenic fatty acids (also from Crepis).
Objective 5: Engineer tung FADX, DGAT2, and other genes from donating organism (tung tree) into commercially important oilseed crop plant such as cotton, soybean, or camelina.
Genes encoding the enzymes for tung oil biosynthesis will be identified by homology-based searches and next-generation high volume pyrosequencing technologies. Other necessary enzymes and proteins will be detected via transcriptomic and proteomic analysis of seeds from tung and other species. Comparisons between different species of tung that produce medium or high amounts of eleostearic will also be used to detect evolution of enzymes well-suited to tung oil production. Mutagenesis studies will identify the active sites and critical residues in these enzymes, thus facilitating the design of engineered forms of important proteins. Model laboratory species of plants and microbes will be used to express combinations of multiple tung genes to find the minimal sets necessary to produce useful levels of eleostearic and other novel fatty acids. A microbial expression system tailored for the bioconversion of low-cost oils into tung-like drying oils will be generated by engineering common yeast strains to efficiently use oils as food, convert the common fatty acids to new valuable lipids, and increase the cellular lipid content.