Characterization and functional analysis of AhGPAT9 gene involved in lipid synthesis in peanut (Arachis hypogaea L.)

Yue Shen; Yi Shen; Yonghui Liu; Yang Bai; Man Liang; Xuyao Zhang; Zhide Chen

doi:10.3389/fpls.2023.1144306

Characterization and functional analysis of AhGPAT9 gene involved in lipid synthesis in peanut (Arachis hypogaea L.)

Front Plant Sci. 2023 Feb 10:14:1144306. doi: 10.3389/fpls.2023.1144306. eCollection 2023.

Authors

Yue Shen¹, Yi Shen¹, Yonghui Liu¹, Yang Bai², Man Liang¹, Xuyao Zhang¹, Zhide Chen¹

Affiliations

¹ Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
² Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing, China.

Abstract

GPAT enzymes (glycerol-3-phosphate 1-O-acyltransferase, EC 2.3.1.15) catalyze the initial and rate-limiting step of plant glycerolipid biosynthesis for membrane homeostasis and lipid accumulation, yet little research has been done on peanuts. By reverse genetics and bioinformatics analyses, we have characterized an AhGPAT9 isozyme, of which the homologous product is isolated from cultivated peanut. QRT-PCR assay revealed a spatio-temporal expression pattern that the transcripts of AhGPAT9 accumulating in various peanut tissues are highly expressed during seed development, followed by leaves. Green fluorescent protein tagging of AhGPAT9 confirmed its subcellular accumulation in the endoplasmic reticulum. Compared with the wild type control, overexpressed AhGPAT9 delayed the bolting stage of transgenic Arabidopsis, reduced the number of siliques, and increased the seed weight as well as seed area, suggesting the possibility of participating in plant growth and development. Meanwhile, the mean seed oil content from five overexpression lines increased by about 18.73%. The two lines with the largest increases in seed oil content showed a decrease in palmitic acid (C16:0) and eicosenic acid (C20:1) by 17.35% and 8.33%, respectively, and an increase in linolenic acid (C18:3) and eicosatrienoic acid (C20:3) by 14.91% and 15.94%, respectively. In addition, overexpressed AhGPAT9 had no significant effect on leaf lipid content of transgenic plants. Taken together, these results suggest that AhGPAT9 is critical for the biosynthesis of storage lipids, which contributes to the goal of modifying peanut seeds for improved oil content and fatty acid composition.

Keywords: AhGPAT9; Arachis hypogaea; evolution analysis; fatty acid; oil content; triacylglycerol.

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (Grant No. 31701461 to YueS), the Jiangsu Agricultural Science and Technology Innovation Fund (Grant No. CX(20)3121 to YueS), the Jiangsu Open Competition Project (Grant No. JBGS(2021)062 to YiS), and the earmarked fund for CARS-13 to ZC.