Drew Sturtevant1,2, Trevor B Romsdahl1,2, Xiao-Hong Yu3, David J Burks1,2, Rajeev K Azad1,2,4, John Shanklin3,5, Kent D Chapman6,7. 1. Department of Biological Sciences, University of North Texas, Denton, TX, USA. 2. BioDiscovery Institute, University of North Texas, Denton, TX, USA. 3. Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA. 4. Department of Mathematics, University of North Texas, Denton, TX, 76203, USA. 5. Biology Department, Brookhaven National Laboratory, Upton, NY, USA. 6. Department of Biological Sciences, University of North Texas, Denton, TX, USA. chapman@unt.edu. 7. BioDiscovery Institute, University of North Texas, Denton, TX, USA. chapman@unt.edu.
Abstract
INTRODUCTION: 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. OBJECTIVES: To examine the distribution of hydroxy fatty acid accumulation within the endosperm and embryo tissues of castor seeds. METHODS: Matrix assisted laser desorption/ionization mass spectrometry imaging 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 acyltransferase while the endosperm pathway appears to remove ricinoleic acid from the PC pool by preferences of phospholipase A (PLA2α) and/or phosphatidylcholine: diacylglycerol cholinephosphotransferase. CONCLUSIONS: 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.
INTRODUCTION: 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. OBJECTIVES: To examine the distribution of hydroxy fatty acid accumulation within the endosperm and embryo tissues of castor seeds. METHODS: Matrix assisted laser desorption/ionization mass spectrometry imaging 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 acyltransferase while the endosperm pathway appears to remove ricinoleic acid from the PC pool by preferences of phospholipase A (PLA2α) and/or phosphatidylcholine: diacylglycerol cholinephosphotransferase. CONCLUSIONS: 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.
Authors: Patrick J Horn; Andrew R Korte; Purnima B Neogi; Ebony Love; Johannes Fuchs; Kerstin Strupat; Ljudmilla Borisjuk; Vladimir Shulaev; Young-Jin Lee; Kent D Chapman Journal: Plant Cell Date: 2012-02-14 Impact factor: 11.277
Authors: Brice A Jarvis; Trevor B Romsdahl; Michaela G McGinn; Tara J Nazarenus; Edgar B Cahoon; Kent D Chapman; John C Sedbrook Journal: Front Plant Sci Date: 2021-04-22 Impact factor: 5.753
Authors: Shanmukh S Salimath; Trevor B Romsdahl; Anji Reddy Konda; Wei Zhang; Edgar B Cahoon; Michael K Dowd; Thomas C Wedegaertner; Kater D Hake; Kent D Chapman Journal: Plant Biotechnol J Date: 2021-02-17 Impact factor: 9.803
Authors: Trevor B Romsdahl; Shrikaar Kambhampati; Somnath Koley; Umesh P Yadav; Ana Paula Alonso; Doug K Allen; Kent D Chapman Journal: Metabolites Date: 2021-03-04