[Reducing the maize amylopectin content through RNA interference manipulation].

Abstract

To regulate the biosynthesis of maize starch, gene segment of starch branch enzyme (SBE) in maize was cloned and an expression vector of small interference RNA with the fragment of antisense gene + sense gene (pCJSBE2b, Fig.1) was constructed. The expression vector of pCJSBE2b was transformed into maize inbred lines by using pollen-tube pathway. Results of PCR amplification and Southern blotting indicated that the aimed gene with the fragment of antisense gene + sense gene had integrated into receptor maize genome (Fig.4,5) and inherited steadily in the transgenic plants (Table 1). Northern hybridization analysis showed that the aimed gene transcribed normally in the transgenic plants, which resulted in a reduction of endogenous SBE mRNA (Fig.6). The analysis of the activity of starch branching enzyme showed that the enzyme activity decreased obviously in the transgenic plants and maximum decrease was 85% compared to the control plants (Fig.7a). Although the total starch content of transgenic plants showed no change compared to the control plants but the amylose content increased to 50% (Fig.7b) in transgenic plants about 27% higher than receptor maize plants.