RNA interference targeting ω-secalin genes differentially affects the processing quality in a wheat T1BL·1RS translocation line

Wheat-rye T1BL·1RS translocation lines are widely used, especially in China, but their processing quality is generally poor. An interfering expression vector targeting the ω-secalin genes was constructed with the 1Bx7 seed-specific promoter. Biolistic-mediated genetic transformation of the wheat cultivar KN199 carrying the T1BL·1RS translocation generated 10 transgenic lines. Two representative transgenic lines, 8-2 and 13-7, were selected for analysis. Compared with the control, the two transformants showed an up to 4.5-fold decrease in total ω-secalins and various levels of decrease in ω-gliadins, γ-gliadins, and low-molecular-weight glutenins. A decrease in high molecular weight (HMW) glutenin 1Bx7 was detected only in 8-2, owing possibly to promoter methylation. Increased levels of α-gliadins were observed in both transformants, but increased levels of HMW glutenins were observed only in 13-7. Line 13-7 showed increases in gluten index, Zeleny sedimentation value, stabilization time, and maximum resistance. Its bread volume was 849.6 mL, an 11.9% increase over that of the control. Line 8-2 showed decreases in these parameters, but its total cake-making quality score was 88, an 17.3% increase over that of the control. The study demonstrates that the same RNAi construct may produce different effects on wheat processing quality and highlights the influence of the vector promoter in RNA interference.