Effects of type I Diacylglycerol O-acyltransferase (DGAT1) genes on soybean (Glycine max L.) seed composition

Sepideh Torabi,Arjun Sukumaran,Milad Eskandari,Sangeeta Dhaubhadel,Sarah E Johnson,Peter Lafayette,Wayne A Parrott,Istvan Rajcan

doi:10.1038/s41598-021-82131-5

Abstract

Type I Diacylglycerol acyltransferase (DGAT1) catalyzes the final step of the biosynthesis process of triacylglycerol (TAG), the major storage lipids in plant seeds, through the esterification of diacylglycerol (DAG). To characterize the function of DGAT1 genes on the accumulation of oil and other seed composition traits in soybean, transgenic lines were generated via trans-acting siRNA technology, in which three DGAT1 genes (Glyma.13G106100, Glyma.09G065300, and Glyma.17G053300) were downregulated. The simultaneous downregulation of the three isoforms in transgenic lines was found to be associated with the reduction of seed oil concentrations by up to 18 mg/g (8.3%), which was correlated with increases in seed protein concentration up to 42 mg/g (11%). Additionally, the downregulations also influenced the fatty acid compositions in the seeds of transgenic lines through increasing the level of oleic acid, up to 121 mg/g (47.3%). The results of this study illustrate the importance of DGAT1 genes in determining the seed compositions in soybean through the development of new potential technology for manipulating seed quality in soybean to meet the demands for its various food and industrial applications.

Highlights

Type I Diacylglycerol acyltransferase (DGAT1) catalyzes the final step of the biosynthesis process of triacylglycerol (TAG), the major storage lipids in plant seeds, through the esterification of diacylglycerol (DAG)
The last step of TAG biosynthesis is the esterification of diacylglycerol (DAG), which can be proceeded through two different pathways of acyl-CoA-dependent and acyl-CoA-independent[14]
The results of this study showed that DGAT1 had the highest transcript level in comparison to the transcript levels of DGAT2 and phospholipid: diacylglycerol acyltransferase (PDAT) in Arabidopsis and soybean

Summary

Introduction

Type I Diacylglycerol acyltransferase (DGAT1) catalyzes the final step of the biosynthesis process of triacylglycerol (TAG), the major storage lipids in plant seeds, through the esterification of diacylglycerol (DAG). While increasing the level of both oil and protein contents in high-yielding soybean varieties is desirable, the simultaneous improvement of the two traits has been challenging due mainly to their quantitative genetic architectures, their negative inter-relationship, as well as their effects on other important agronomic traits, including y ield[1,2,3]. The acyl-CoA-independent TAG synthesis is catalyzed by phospholipid: diacylglycerol acyltransferase (PDAT), which uses phospholipids and DAG as substrates to produce TAG1 5,16 (Fig. 1). Among the different DGATgene families, DGAT1 genes play more important roles in TAG biosynthesis and accumulation in developing seeds of soybean and Arabidopsis than other types of identified DGATgenes such as DGAT2 and DGAT319–22

Methods

Results

Conclusion