Abstract: Starch branching enzyme (SBE) plays an important role in the synthesis of starch. We used RNA interference (RNAi) to silence the SBE gene (SBEI) to research the effect of SBEI silencing in maize. The xylA gene from Escherichia coli encoding xylose isomerase was used as a selective marker. We constructed the expression vector pBAC418 containing the CaMV 35S promotor driving xylA and the reverse repeat sequence of SBEI driven by its corresponding promotor with biolistic PDS1000/He to bombard maize calli induced from the elite inbred lines. The selection was made on media containing 50% concentrations of xylose. We obtained 7 transformed plantlets. Gene integration was confirmed in 5 transformed plantlets by DNA dot blot analysis and PCR-Southern hybridization of xylA and FAD2 intron. Total protein, starch, oil and amylose contents of regenerated plants were detected. Oil content of regenerated plants showed no significant change, the total protein content was increased, and starch content was decreased a little. Mean amylose content increased 9.8% in transgenic maize lines.

Key words: amylose, maize, RNAi, SBEI