Genetic and Biochemical Investigation of Seed Fatty Acid Accumulation in Arabidopsis

Chinedu Charles Nwafor; Delin Li; Ping Qin; Long Li; Wei Zhang; Yuanwei Zhou; Jingjing Xu; Yongtai Yin; Jianbo Cao; Limin He; Fu Xiang; Chao Liu; Liang Guo; Yongming Zhou; Edgar B Cahoon; Chunyu Zhang

doi:10.3389/fpls.2022.942054

Genetic and Biochemical Investigation of Seed Fatty Acid Accumulation in Arabidopsis

Front Plant Sci. 2022 Jul 6:13:942054. doi: 10.3389/fpls.2022.942054. eCollection 2022.

Authors

Chinedu Charles Nwafor^{1

2}, Delin Li¹, Ping Qin¹, Long Li¹, Wei Zhang³, Yuanwei Zhou⁴, Jingjing Xu¹, Yongtai Yin⁵, Jianbo Cao⁶, Limin He⁶, Fu Xiang⁷, Chao Liu¹, Liang Guo¹, Yongming Zhou¹, Edgar B Cahoon⁸, Chunyu Zhang¹

Affiliations

¹ National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
² Department of Crop Science, Faculty of Agriculture, University of Benin, Benin City, Nigeria.
³ Department of Biology, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China.
⁴ Yichang Academy of Agricultural Science, Yichang, China.
⁵ Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
⁶ Public Laboratory of Electron Microscopy, Huazhong Agricultural University, Wuhan, China.
⁷ Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains and College of Biology and Agriculture Resource, Huanggang Normal University, Huanggang, China.
⁸ Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, United States.

Abstract

As a vegetable oil, consisting principally of triacylglycerols, is the major storage form of photosynthetically-fixed carbon in oilseeds which are of significant agricultural and industrial value. Photosynthesis in chlorophyll-containing green seeds, along with photosynthesis in leaves and other green organs, generates ATP and reductant (NADPH and NADH) needed for seed fatty acid production. However, contribution of seed photosynthesis to fatty acid accumulation in seeds have not been well-defined. Here, we report the contribution of seed-photosynthesis to fatty acid production by probing segregating green (photosynthetically-competent) and non-green or yellow (photosynthetically-non-competent) seeds in siliques of an Arabidopsis chlorophyll synthase mutant. Using this mutant, we found that yellow seeds lacking photosynthetic capacity reached 80% of amounts of oil in green seeds at maturity. Combining this with studies using shaded siliques, we determined that seed-photosynthesis accounts for 20% and silique and leaf/stem photosynthesis each account for ~40% of the ATP and reductant for seed oil production. Transmission electron microscopy (TEM) and pyridine nucleotides and ATP analyses revealed that seed photosynthesis provides ATP and reductant for oil production mostly during early development, as evidenced by delayed oil accumulation in non-green seeds. Transcriptomic analyses suggests that the oxidative pentose phosphate pathway could be the source of carbon, energy and reductants required for fatty acid synthesis beyond the early stages of seed development.

Keywords: Arabidopsis; NADPH; chlorophyll synthase; fatty acid biosynthesis; oil bodies; oxidative pentose phosphate pathway; photosynthesis; seed development.