Title: Tissue-specific differences in metabolites and transcripts contribute to the heterogeneity of ricinoleic acid accumulation in Ricinus communis L. (castor) seeds

Abstract

Castor (Ricinus communis L.) seeds are valued for their production of oils which can comprise up to 90% hydroxy-fatty acids (ricinoleic acid). Castor oil contains mono-, di- and tri- ricinoleic acid containing triacylglycerols (TAGs). Although the enzymatic synthesis of ricinoleic acid is well described, the differential compartmentalization of these TAG molecular species has remained undefined. To examine the distribution of hydroxy fatty acid accumulation within the endosperm and embryo tissues of castor seeds. Matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to map the distribution of triacylglycerols in tissue sections of castor seeds. In addition, the endosperm and embryo (cotyledons and embryonic axis) tissues were dissected and extracted for quantitative lipidomics analysis and Illumina-based RNA deep sequencing. Results: This study revealed an unexpected heterogeneous tissue distribution of mono-, di- and tri- hydroxy-triacylglycerols in the embryo and endosperm tissues of castor seeds. Pathway analysis based on transcript abundance suggested that distinct embryo- and endosperm-specific mechanisms may exist for the shuttling of ricinoleic acid away from phosphatidylcholine (PC) and into hydroxy TAG production. The embryo-biased mechanism appears to favor removal of ricinoleic acid from PC through phophatidylcholine: diacylglycerol acylytransferase (PDAT) while the endosperm pathway appears to remove ricinoleic acid frommore » the PC pool by preferences of phospholipase A (PLA₂α) and/or phosphatidylcholine: diacylglycerol cholinepshphotransferase PDCT. In conclusion, collectively, a combination of lipidomics and transcriptomics analyses revealed previously undefined spatial aspects of hydroxy fatty acid metabolism in castor seeds. These studies underscore a need for tissue-specific studies as a means to better understand the regulation of triacylglycerol accumulation in oilseeds.« less

Authors:

Sturtevant, Drew  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3152-0394"

Romsdahl, Trevor B. ^[1]; Yu, Xiao -Hong  ^[2];

• Search DOE PAGES for author "Yu, Xiao -Hong"
• Search DOE PAGES for ORCID "0000-0003-2352-2023"

Burks, David J.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-0098-265X"

Azad, Rajeev K.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6874-6146"

Shanklin, John  ^[3];

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• Search DOE PAGES for ORCID "0000-0002-6774-8043"

Chapman, Kent D.  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-0489-3072"

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+ Show Author Affiliations

1. Univ. of North Texas, Denton, TX (United States)
2. Stony Brook Univ., Stony Brook, NY (United States)
3. Stony Brook Univ., Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

Publication Date:

Thu Jan 03 00:00:00 EST 2019

Research Org.:

Brookhaven National Lab. (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1491699

Report Number(s):

BNL-210897-2019-JAAM
Journal ID: ISSN 1573-3882

Grant/Contract Number:  

SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Metabolomics

Additional Journal Information:

Journal Volume: 15; Journal Issue: 1; Journal ID: ISSN 1573-3882

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; MALDI; RNA-Seq; Castor; Ricinoleic acid; Lipidomics; Hydroxy fatty acids