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United States Department of Agriculture

Agricultural Research Service


Location: Plant Physiology and Genetics Research

2009 Annual Report

1a. Objectives (from AD-416)
Many plant species produce high amounts of industrially important fatty acids (e.g., hydroxy fatty acids) in their seeds, but the plants generally lack agronomic traits that permit these oils to be produced on a large scale for industrial utilization. The objective of this research program is to discover the genetic basis for the production of these high-value oils and use these genes for production of the oils in robust, non-food crop platforms. Cotton is exceptionally well positioned to serve as a platform for production of high value oils because the main economic driver for this crop is cotton fiber. The seed is generally viewed as a lower valued by-product, and raising the value of the seed through production of industrially important oils would increase farm gate value of the crop and provide society with renewable, sustainable sources of oil that are otherwise obtained from non-renewable petroleum. In addition, high-risk/high-payoff research will be conducted to determine if industrial oils can be produced in vegetative (e.g., leaves and stems) parts of plants. The rationale is that vegetative plant biomass is significantly greater than seed tissues, and by developing methods to produce oil ectopically in leaves and stems, the amount of oil obtained per hectare of land can be substantially increased.

1b. Approach (from AD-416)
Various species and hybrids of Lesquerella will be analyzed to identify genes involved in the production of hydroxy fatty acids. Enzyme functionality will be investigated by expression in yeast cells, and cellular properties will be evaluated through expression in plant cell culture. Candidate enzymes will be expressed in transgenic Arabidopsis, including both developing seed and leaf tissues. Enzyme stability and regulation (primarily by temperature) will be investigated using western blotting and half-life studies. Select genes will be expressed in transgenic cottonseed to evaluate this crop as a platform for production of industrially important oils. Production of hydroxy fatty acids in non-seed tissues will be evaluated in various wild-type and mutant Arabidopsis plants. Documents SCA with University of North Texas. Formerly 5347-21410-004-14S (8/08).

3. Progress Report
Gene transfer vectors were constructed using the castor bean hydroxylase DNA sequence for production of high value hydroxy fatty acids in plants. The hydroxylase gene was subsequently used in transformation experiments to introduce the gene into a variety of plants including 1) the model plant Arabidopsis, 2) a mutant Arabidopsis plant that is known to accumulate oil in leaves and stems, in addition to seeds, and 3) several species of Lesquerella, which already accumulate fairly high amounts of hydroxyl fatty acids. First generation transgenic plants have been obtained, and studies are ongoing to identify subsequent generations of plants that are stably expressing the hydroxylase gene. Experiments were conducted to study the stability and regulation of fatty acid desaturases in plants. These enzymes are closely related to hydroxylase enzymes, and knowledge of their regulation will allow for more efficient production of desired fatty acids in plant cells. This agreement is monitored by the ADODR through direct interaction and evaluation of experiments conducted by the scientist supported through this SCA. The visiting scientist is currently working directly under his supervision at ALARC.

4. Accomplishments

Last Modified: 07/26/2017
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