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The biochemistry of headgroup exchange during triacylglycerol synthesis in canola
Author(s) -
Bai Shuangyi,
Wallis James G.,
Denolf Peter,
Engelen Steven,
Bengtsson Jesse D.,
Van Thournout Michel,
Dierickx Jo,
Haesendonckx Boris,
Browse John
Publication year - 2020
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14709
Subject(s) - canola , arabidopsis , brassica , isozyme , biochemistry , arabidopsis thaliana , polyunsaturated fatty acid , biology , metabolism , diacylglycerol kinase , mutant , gene , enzyme , botany , fatty acid , protein kinase c
SUMMARY Many pathways of primary metabolism are substantially conserved within and across plant families. However, significant differences in organization and fluxes through a reaction network may occur, even between plants in closely related genera. Assessing and understanding these differences is key to appreciating metabolic diversity, and to attempts to engineer plant metabolism for higher crop yields and desired product profiles. To better understand lipid metabolism and seed oil synthesis in canola ( Brassica napus ), we have characterized four canola homologues of the Arabidopsis ( Arabidopsis thaliana ) ROD1 gene. AtROD1 encodes phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), the enzyme that catalyzes a major flux of polyunsaturated fatty acids (PUFAs) in oil synthesis. Assays in yeast indicated that only two of the canola genes, BnROD1.A3 and BnROD1.C3 , encode active isozymes of PDCT, and these genes are strongly expressed during the period of seed oil synthesis. Loss of expression of BnROD1.A3 and BnROD1.C3 in a double mutant, or by RNA interference, reduced the PUFA content of the oil to 26.6% compared with 32.5% in the wild type. These results indicate that ROD1 isozymes in canola are responsible for less than 20% of the PUFAs that accumulate in the seed oil compared with 40% in Arabidopsis. Our results demonstrate the care needed when translating results from a model species to crop plants.