Absence of amylose in sweet potato [Ipomoea batatas (L.) Lam.] following the introduction of granule-bound starch synthase I cDNA

The full-length sense cDNA for sweet potato granule-bound starch synthase I (GBSSI) driven by the granule CaMV 35S promoter was introduced into the sw eet potato by Agrobacterium tumefaciens-mediated transformation. Out of the 26 transgenic plants obtained, one plant showed the absence of amylose in the tuberous root as determined by the iodine colorimetric method. Electrop horesis analysis failed to detect the GBSSI protein, suggesting that gene s ilencing of the GBSSI gene occurred in the transgenic sweet potato plant. T hese results demonstrate that starch composition in the tuberous root of sw eet potato can be altered by genetic transformation.