Genome-wide association study reveals useful QTL and genes controlling the fatty acid composition in rice bran oil using Vietnamese rice landraces.

ABSTRACT

In rice (Oryza sativa L.), rice bran contains valuable nutritional constituents, such as high unsaturated fat content, tocotrienols, inositol, γ-oryzanol, and phytosterols, all of which are of nutritional and pharmaceuticals interest. There is now a rising market demand for rice bran oil, which makes research into their content and fatty acid profile an area of interest. As it is evident that lipid content has a substantial impact on the eating, cooking, and storage quality of rice, an understanding of the genetic mechanisms that determine oil content in rice is of great importance, equal to that of rice quality. Therefore, in this study, we performed a genome-wide association study on the composition and oil concentration of 161 Vietnamese rice varieties. Five categories of fatty acids in rice bran were discovered and the bran oil concentration profile in different rice accessions was identified. We also identified 229 important markers related to the fatty acid composition of bran oil, distributed mainly on chromosomes 1 and 7. Seven quantitative trait loci and five potential genes related to unsaturated fatty acid content were detected, including OsKASI, OsFAD, OsARF, OsGAPDH, and OsMADS29. These results provide insights into the genetic basis of rice bran oil composition, which is pivotal to the metabolic engineering of rice plants with desirable bran oil content through candidate genes selection.