Increased expression of fatty acid and ABC transporters enhances seed oil production in camelina

Guangqin Cai,Jianwu Li,Yongming Zhou,Sang-Chul Kim,Geliang Wang,Xuemin Wang

doi:10.1186/s13068-021-01899-w

Abstract

BackgroundLipid transporters play an essential role in lipid delivery and distribution, but their influence on seed oil production in oilseed crops is not well studied.ResultsHere, we examined the effect of two lipid transporters, FAX1 (fatty acid export1) and ABCA9 (ATP-binding cassette transporter subfamily A9) on oil production and lipid metabolism in the oilseed plant Camelina sativa. Overexpression (OE) of FAX1 and ABCA9 increased seed weight and size, with FAX1-OEs and ABCA9-OEs increasing seed length and width, respectively, whereas FAX1/ABCA9-OEs increasing both. FAX1-OE and ABCA9-OE displayed additive effects on seed oil content and seed yield. Also, OE of FAX1 and ABCA9 affected membrane lipid composition in developing pods, especially on phosphatidylcholine, phosphatidylethanolamine, and phosphatidylglycerol. The expression of some genes involved in seed oil synthesis, such as DGAT2, PDAT1, and LEC1, was increased in developing seeds of FAX1- and/or ABCA9-OEs.ConclusionThese results indicate that increased expression of FAX1 and ABCA9 can potentially be applied to improving camelina oil production.

Highlights

Lipid transporters play an essential role in lipid delivery and distribution, but their influence on seed oil production in oilseed crops is not well studied
Overexpression of FAX1 and ABCA9 in camelina To investigate the function of FAX1 and ABCA9 in camelina, we overexpressed Arabidopsis FAX1 and ABCA9 genomic DNAs under the control of the cauliflower mosaic virus (CaMV)-35S promoter (Fig. 1a)
The production of FAX1-HA and ABCA9-Flag in camelina was confirmed by immunoblotting using anti-HA and anti-Flag antibodies, respectively (Fig. 1b, upper panel)

Summary

Introduction

Lipid transporters play an essential role in lipid delivery and distribution, but their influence on seed oil production in oilseed crops is not well studied. Fatty acids (FAs) are the major and essential component of membrane lipids and important energy stores for metabolism and cellular energy homeostasis [1, 2]. FAs participate in many regulatory processes in organismal growth, development, and stress responses. FAs are synthesized in plastids and exported out of plastids and to endoplasmic reticulum (ER) for elongation, desaturation, and other embellishments [3, 4]. FAX1 (fatty acid export 1), FA associated with ER is involved in the biosynthesis of triacylglycerol (TAG). An ER-localized ATP-binding cassette (ABC) transporter subfamily A, ABCA9, was described to transport FA/acyl-CoA to the ER [8]. Developing seeds of ABCA9-knockout mutant (abca9) incorporated less 14C-oleoyl-CoA into TAG compared with WT seeds. OE of ABCA9 enhanced TAG deposition by

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Discussion

Conclusion