Leaf lipidome and transcriptome profiling of Portulaca oleracea: characterization of lysophosphatidylcholine acyltransferase.

Venkateshwari, V. and Anitha, Vijayakumar and Arun Kumar, V. and Prasanna Anjaneya Reddy, Lebaka and Malathi, Srinivasan and Ram, Rajasekharan (2018) Leaf lipidome and transcriptome profiling of Portulaca oleracea: characterization of lysophosphatidylcholine acyltransferase. Planta, 248 (2). pp. 347-367.

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Abstract

Poly-unsaturated fatty acids (PUFAs) are gaining importance due to their innumerable health benefits, and hence, understanding their biosynthesis in plants has attained prominence in recent years. The most common source of PUFAs is of marine origin. Although reports have identified Portulaca oleracea (purslane) as a leaf source of omega-3 fatty acids in the form of alpha-linolenic acid (ALA), the mechanism of ALA accumulation and its distribution into various lipids has not been elucidated. Here, we present the lipid profiles of leaves and seeds of several accessions of P. oleracea. Among the nineteen distinct accessions, the RR04 accession has the highest amount of ALA and is primarily associated with galactolipids. In addition, we report the transcriptome of RR04, and we have mapped the potential genes involved in lipid metabolism. Phosphatidylcholine (PC) is the major site of acyl editing, which is catalyzed by lysophosphatidylcholine acyltransferase (LPCAT), an integral membrane protein that plays a major role in supplying oleate to the PC pool for further unsaturation. Our investigations using mass spectrometric analysis of leaf microsomal fractions identified LPCAT as part of a membrane protein complex. Both native and recombinant LPCAT showed strong acyltransferase activity with various acyl-CoA substrates. Altogether, the results suggest that ALA-rich glycerolipid biosynthetic machinery is highly active in nutritionally important Portulaca leaves. Furthermore, lipidome, transcriptome, and mass spectrometric analyses of RR04 provide novel information for exploring Portulaca as a potential resource and a model system for studying leaf lipid metabolism.

Item Type:	Article
Uncontrolled Keywords:	Alpha-linolenic acid · Galactolipids · Triacylglycerol · Phosphatidylcholine · Fatty acid · Microsomal membrane
Subjects:	500 Natural Sciences and Mathematics > 10 Plants 600 Technology > 08 Food technology > 19 Lipids-oils/fats
Divisions:	Dept. of Lipid Science
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	29 Aug 2018 05:38
Last Modified:	05 Oct 2018 06:43
URI:	http://ir.cftri.res.in/id/eprint/13826

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