• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.282-290
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• 2019

Cuphea viscosissima plants accumulate medium-chain fatty acids (MCFAs), i.e., those containing 8 ~ 14 carbons, in their seeds, in addition to the longer carbon chain fatty acids (≥16 carbons) found in a variety of plant species. Previous studies have reported the existence of three C. viscosissima MCFA-producing acyl-acyl carrier protein (ACP) thioesterases with different substrate specificities. In this study, CvFatB4, a novel cDNA clone encoding an acyl-ACP thioesterase (EC 3.1.2.14), was isolated from developing C. viscosissima seeds. Sequence alignment of the deduced amino acid sequence revealed that four catalytic residues for thioesterase activity are conserved and a putative N-terminal chloroplast transit peptide is present. Overexpression of CvFatB4 cDNA, which was under the control of the cauliflower mosaic virus 35S promoter, in Arabidopsis thaliana led to an increase in 16:0 fatty acid (palmitate) levels in the seed oil at the expense of 18:1 and other non-MCFAs.

• Journal of Applied Biological Chemistry
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• v.53 no.2
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• pp.65-70
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• 2010

Medium-chain fatty acids (MCFA) are composed of 8-12 carbon atoms, and are found in coconut, cuphea, and palm kernel oil. MCFA were introduced into clinical nutrition in the 1950s for dietary treatment of malabsorption syndromes because of their rapid absorption and solubility. Recently, MCFA have been applied to Gastrointestinal Permeation Enhancement Technology (GIPET), which is one of the most important parts in drug delivery system in therapeutics. Therefore, to accumulate the MCFA in seed oil of rapeseed, much effort has been conducted by classical or molecular breeding. Laurate can be successfully accumulated up to 60 mol% in the seed oil of rapeseed by the expression of bay thioesterase (Uc FatB1) alone or crossed with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT) under the control of a napin seed-storage protein promoter. Also, caprylate and caprate were obtained 7 mol% and 29 mol%, respectively, from plants over-expressing of the medium-chain specific thioesterase (Ch FatB2) alone or together with the chain-length-specific condensing enzyme (Ch KASIV). Despite the success of some research in utilizing parallel classical and molecular breeding to produce MCFA, commercially available seed oils have for the most part, not been realized. Recent research in the field of developing MCFA-enriched transgenic plants has established that there is no single rate-limiting step in the production of the target fatty acids. The purpose of this article is to review some of the recent progress in understanding the mechanism and regulation of MCFA production in seed oil of rapeseed.