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

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.

Genotypic and Phenotypic Diversity of Endemic Golden Camellias Collected from the North of Vietnam.

Golden Camellias have recently been used as a food, cosmetic, and traditional medicine in China and Vietnam. Forty-two species have natural distribution in Vietnam, of which thirty-two species were considered endemic species of this country. The morphology of leaves and flowers of these species were similar; therefore, their taxonomic identification usually needed experts and the authentication has often been confused among species. Our study aims to describe the genetic diversity and the relationship of six species Camellia phanii, Camellia tamdaoensis, Camellia tienii, Camellia flava, Camellia petelotii and Camellia euphlebia by using three chloroplast DNA-barcodes: matK, rbcL and trnH-psbA. We also clarified the significant differences in anatomical characteristics of midvein and blade of their leaves, which suggested the possibility to use these criteria in taxonomy. In addition, preliminary chemical profiles of the methanolic extracts of leaves from six Golden Camellias such as total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and chlorogenic acids content (TCGAs) also showed the diversity among them. Interestingly, the discrimination on the catechins profile among six species followed the same tendency with the genetic distance on the phylogeny tree suggesting that catechins (i. e., discriminative catechins) can be biomarkers for the chemotaxonomy of these six Golden Camellias.