Abstract
Grain hardness of wheat is determined by the Hardness (Ha)-locus region, which contains three similar genes; puroindoline-a (Pina), puroindoline-b (Pinb) and GSP-1. Although Krishnamurthy and Giroux (2001) showed that expression of Pina or Pinb in transgenic rice seeds reduced rice grain hardness, functional relationships of the three genes have not yet been clarified.
In this study, we produced the transgenic rice plants harboring large genomic fragments of the wheat Ha-locus region containing Pina and GSP-1 genes by Agrobacterium-mediated transformation (Nakano et al. 2005). We confirmed homozygosity of the T-DNAs in the four independent T2 lines by using fluorescence in situ hybridization (FISH) and DNA gel blot analyses. RT-PCR and Western blot analyses using the T3 seeds showed that Pina and GSP-1 were expressed in endosperms of the transgenic rice plants. We are now trying to examine functional contribution to grain hardness in the transgenic rice plants.
