Generation of transgenic wheat lines with altered expression levels of 1Dx5 high-molecular weight glutenin subunit by RNA interference

In recent years, high molecular weight glutenin subunit (HMW-GS) null mutants have been found to be useful for studying the contribution of HMW-GS to the flour processing quality of wheat (Triticum aestivum L. em. Thell.). However, few reports have dealt with the development and characterization of such variants. In the present study, the RNA interference (RNAi) method was applied to Bobwhite wheat, which has five actively expressed HMW-GS genes (namely1Ax2*,1Dx5,1Bx7,1By9, 1Dy10), with the aim of silencing the expression of 1Dx5. Out of the six transgenic events characterized,1Dx5 expression was completely blocked in four transgenic events (L I -L4), and partially reduced in the other two (L5, L6). In contrast, the protein levels of 1Ax2*, 1By9 and 1Dy 10 were not significantly affected in any of the six transgenic events. Interestingly, 1Bx7 protein accumulation was negatively affected in all six events and their progenies.1Dx5 transcript levels in developing seeds at 15 days after pollination (DAP) were undetectable in L1 and dramatically reduced in L5. The silencing of 1Dx5 expression caused a substantial decrease in flour processing quality based on Farinograph, gluten and Zeleny tests. Collectively, our data suggest that RNAi is useful for silencing HMW-GS genes. The resultant transgenic lines are of value for studying the contributions of specific HMW-GS to wheat flour processing quality. (c) 2007 Elsevier Ltd. All rights reserved.