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Recruiting a new substrate for triacylglycerol synthesis in plants: the monoacylglycerol acyltransferase pathway
Petrie, JR and Vanhercke, T and Shrestha, P and El Tahchy, A and White, A and Zhou, X-R and Liu, Q and Mansour, MP and Nichols, PD and Singh, SP, Recruiting a new substrate for triacylglycerol synthesis in plants: the monoacylglycerol acyltransferase pathway, PLoS One, 7, (4) Article e35214. ISSN 1932-6203 (2012) [Refereed Article]
Copyright 2012 Petrie et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
Monoacylglycerol acyltransferases (MGATs) are predominantly associated with lipid absorption and resynthesis in the animal intestine where they catalyse the first step in the monoacylglycerol (MAG) pathway by acylating MAG to form diacylglycerol (DAG). Typical plant triacylglycerol (TAG) biosynthesis routes such as the Kennedy pathway do not include an MGAT step. Rather, DAG and TAG are synthesised de novo from glycerol-3-phosphate (G-3-P) by a series of three subsequent acylation reactions although a complex interplay with membrane lipids exists.
We demonstrate that heterologous expression of a mouse MGAT acyltransferase in Nicotiana benthamiana significantly increases TAG accumulation in vegetative tissues despite the low levels of endogenous MAG substrate available. In addition, DAG produced by this acyltransferase can serve as a substrate for both native and coexpressed diacylglycerol acyltransferases (DGAT). Finally, we show that the Arabidopsis thaliana GPAT4 acyltransferase can produce MAG in Saccharomyces cerevisiae using oleoyl-CoA as the acyl-donor.
This study demonstrates the concept of a new method of increasing oil content in vegetative tissues by using MAG as a substrate for TAG biosynthesis. Based on in vitro yeast assays and expression results in N. benthamiana, we propose that co-expression of a MAG synthesising enzyme such as A. thaliana GPAT4 and a MGAT or bifunctional M/DGAT can result in DAG and TAG synthesis from G-3-P via a route that is independent and complementary to the endogenous Kennedy pathway and other TAG synthesis routes.
|Item Type:||Refereed Article|
|Keywords:||triacylglycerol, MGATs, TAG|
|Research Division:||Biological Sciences|
|Research Group:||Biochemistry and cell biology|
|Research Field:||Analytical biochemistry|
|Objective Division:||Expanding Knowledge|
|Objective Group:||Expanding knowledge|
|Objective Field:||Expanding knowledge in the chemical sciences|
|UTAS Author:||Nichols, PD (Dr Peter Nichols)|
|Web of Science® Times Cited:||124|
|Deposited By:||Ecology and Biodiversity|
|Downloads:||113 View Download Statistics|
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