Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 4/9/2010
Publication Date: 7/25/2010
Citation: Chen, G.Q. 2010. Metabolic Engineering Pathways in Lesquerella fendleri (L.) for Safe Hydroxy Fatty Acid Production. Third Annual Congress of Industrial Biotechnology, July 25-27, 2010, Dalian, China. Interpretive Summary:
Technical Abstract: Castor oil contains 90% ricinoleate (C18:1OH) which is the conventional source of hydroxyl fatty acid. Ricinoleate and its derivatives are used as raw materials for numerous industrial products. The production of castor oil, however, is hampered by the presence of the toxin ricin and hyper-allergic 2S albumins in castor seed. Lesquerella fendleri (L.), being developed as a new industrial oilseed crop in U.S., is valued for its unusual hydroxy fatty acid (HFA). The HFA in L. fendleri was named lesquerolic acid (C20:1OH), derived by a 2 carbon elongation of ricinoleate. By suppressing the elongation step in L. fendleri through genetic engineering, it is possible to generate a L. fendleri crop producing ricinoleate. As a part of the genetic approach, we have established a seed development staging system in L. fendleri, which can be applied for illustrating a wide range of morphological, physiological and biochemical changes during seed development. Three major physiological periods of seed development, characteristic of most seed plants, were exhibited in L. fendleri. The accumulation curves of storage lipids, proteins and other components of dry weights displayed a sigmoidal pattern during seed development. We found three HFAs accumulated consecutively, with initial appearance of ricinoleate, followed by lesqurolate and auricolate (C20:2OH). Only lesqurolate reached to predominant levels at 50 to 55% of total lipids. Besides, we quantified the transcript level of three lipid genes, LfFAH (bifuntional oleate 12-hydroxylase:desaturase), LfKCS3 (3-ketoacyl-CoA synthase) and LfFen1 (oleate 12-desaturase). Although all of three genes displayed a bell-shaped pattern, they had different starting background levels and maximum inductions. As all these measurements are in parallel with the same time course, it allowed us to investigate the relationships among HFA accumulation, gene expression and seed development.