Production of high oleic rice grains by suppressing the expression of the OsFAD2-1 gene.

The composition of rice (Oryza sativa L.) grain fatty acids (18% palmitic acid, 36% oleic acid and 37% linoleic acid) is suboptimal for rice storage and utilisation of rice bran oil as food grade oil or a source of biodiesel. Genetic manipulation of fatty acid composition in rice bran oil to increase oleic acid levels at the expense of linoleic acid and palmitic acid would not only add extra value to the rice, but also enhance health benefits for consumers. Four putative rice microsomal Δ12-fatty acid desaturase (OsFAD2) genes were identified as potentially important target genes to achieve this improvement. Reverse transcription-PCR analysis indicated that OsFAD2-1 was the most highly expressed gene in rice grains. RNA interference (RNAi) suppression of the expression of OsFAD2-1 resulted in an increase of oleic acid and a reduction of linoleic and palmitic acids in T3 grains. The research here showed that in the rice grains, the OsFAD2-1 enzyme was an effective target for raising oleic acid levels at the expense of the oxidatively unstable linoleic acid and the cholesterol-raising palmitic acid.