Arabidopsis cytosolic acyl-CoA-binding proteins function in determining seed oil composition

A - Papers appearing in refereed journals

Guo, Z. H., Ye, Z. W., Haslam, R. P., Michaelson, L. V., Napier, J. A. and Chye, M. L. 2019. Arabidopsis cytosolic acyl-CoA-binding proteins function in determining seed oil composition. Plant Direct. 3 (12), p. e00182.

AuthorsGuo, Z. H., Ye, Z. W., Haslam, R. P., Michaelson, L. V., Napier, J. A. and Chye, M. L.
Abstract

As plant seed oils provide animals with essential fatty acids (FAs), genes that regulate plant lipid metabolism have been used in genetic manipulation to improve dietary seed oil composition and benefit human health. Herein, the Arabidopsis thaliana cytosolic acyl-CoA-binding proteins (AtACBPs), AtACBP4, AtACBP5, and AtACBP6 were shown to play a role in determining seed oil content by analysis of atacbp (atacbp4, atacbp5, atacbp6, atacbp4atacbp5, atacbp4atacbp6, atacbp5atacbp6, and atacbp4atacbp5atacbp6) seed oil content in comparison with the Col-0 wild type (WT). Triacylglycerol (TAG) composition in electrospray ionization-mass spectrometer (ESI-MS) analysis on atacbp6 seed oil showed a reduction (−50%) of C58-TAGs in comparison with the WT. Investigations on fatty acid composition of atacbp mutants indicated that 18:2-FA accumulated in atacbp6 and 18:3-FA in atacbp4, both at the expense of 20:1-FA. As TAG composition can be modified by acyl editing through phosphatidylcholines (PC) and lysophosphatidylcholines (LPC), total PC and LPC content in atacbp6 mature seeds was determined and ESI-MS analysis revealed that LPC had increased (+300%) at the expense of PC. Among all the 14 tested PC species, all (34:1-, 34:2-, 34:3-, 34:4-, 34:5-, 34:6-, 36:2-, 36:3-, 36:5-, 36:6-, 38:2-, 38:3-, and 38:4-PCs) but 36:4-PC were lower in atacbp6 than the WT. In contrast, all LPC species (16:0-, 18:1-, 18:2-, 18:3-, and 20:1-LPC) examined were elevated in atacbp6. LPC abundance also increased in atacbp4atacbp5, but not atacbp4 and atacbp5. Interestingly, when LPC composition in atacbp4atacbp5 was compared with atacbp4 and atacbp5, significant differences were observed between atacbp4atacbp5 and each single mutant, implying that AtACBP4 and AtACBP5 play combinatory roles by affecting LPC (but not PC) biosynthesis. Furthermore, PC-related genes such as those encoding acyl-CoA:lysophphosphatidylcholine acyltransferase (LPCAT1) and phospholipase A2 alpha (PLA2α) were upregulated in atacbp6 developing seeds. A model on the role of AtACBP6 in modulating TAG through regulating LPCAT1 and PLA2α expression is proposed. Taken together, cytosolic AtACBPs appear to affect unsaturated TAG content and are good candidates for engineering oil crops to enhance seed oil composition.

KeywordsDeveloping seeds; Lysophosphatidylcholine; Phosphatidylcholine; Reversible lysophosphatidylcholine acyltransferase; Triacylglycerols
Year of Publication2019
JournalPlant Direct
Journal citation3 (12), p. e00182
Digital Object Identifier (DOI)doi:10.1002/pld3.182
Open accessPublished as bronze (free) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeTPM - Tailoring Plant Metabolism - Work package 1 (WP1) - High value lipids for health and industry
Designing oilseeds for nutrition and health
Publisher's version
Output statusPublished
Publication dates
Online04 Dec 2019
Publication process dates
Accepted24 Oct 2019
ISSN2475-4455
PublisherWiley

Permalink - https://repository.rothamsted.ac.uk/item/96zvv/arabidopsis-cytosolic-acyl-coa-binding-proteins-function-in-determining-seed-oil-composition

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