Annual Report 2003

culture response of the R1 and R2 plantswere examined. Plant regeneration frequenciesin the R1 (82%) and R2 (99%) generationswere significantly higher than that ofR0 (53%) (Fig. 2).Foreign genes (35S + npt) were introducedinto immature embryos of “NorinNo.67, R2” using a particle gun (BiolisticPDS-1000/He). To date, 31 geneticin-resistantplants have been regenerated and 30plants showed positive response in PCRanalysis. At present, two plants out of sixPCR-positive ones showed positive responsein Southern analysis (Fig. 3). Application ofthis knowledge should facilitate the generationof transgenic wheat. We recentlystarted research to produce wheat linesresistant to pre-harvest sprouting by introducinga VP-1 homologue gene (Nakamuraand Toyama 2001).Novel and efficient rice transformationmethod mediated by AgrobacteriumHiroshi Tanaka, Yasunori Koga-Ban, Yuko OtakeBiotechnology DepartmentFig. 1Outline of Transformation.We developed a novel rice transformationmethod using germinating seeds. Thetransformation efficiency of this method wascomparable to or better than that of the conventionalmethod 1) in all tested varieties. Wehave described the experimental protocol asa novel rice transformation method, and distributedit to public research laboratories fortechnology transfer.The conventional Agrobacterium methodof rice transformation was unique in thatAgrobacterium infected into dedifferentiatingtissues (callus). However, it has beenreported that some of the crops have difficultyin regeneration once reaching the stageof callus. Since it took about 3 months forthe conventional transformation method toobtain transgenic rice plants, it has been amajor goal to develop an efficient and stabletransformation method requiring less time.We attempted to develop such a novel transformationsystem, which could be applied toother major crops including maize, barelyand wheat.46 Annual Report 2003