Improvement of rice (Oryza sativa L.) seed oil quality through introduction of a soybean microsomal omega-3 fatty acid desaturase gene

Microsomal omega-3 fatty acid desaturase is an essential enzyme in the production of the n-3 polyunsaturated fatty acid α-linolenic acid during the seed developing stage. We have constructed a chimeric gene consisting of a maize Ubil-P-int and a soybean GmFAD3 cDNA, which was introduced into rice plants by Agrobacterium-mediated transformation. Ten transformants containing the chimeric gene were established and expression subsequently confirmed by Northern blotting. Furthermore, α-linolenic acid content of the T₁ seeds increased dramatically up to tenfold that of the control, and this phenotype was also stably inherited in the T₂ and T₃ progenies. These results demonstrate that the α-linolenic acid content of rice seed oil can easily be altered using the combination of a high-activity promoter and a GmFAD3 gene.