高分子量谷蛋白单亚基缺失对软质小麦宁麦9号加工品质的影响

摘要

基因敲除是研究高分子量谷蛋白(HMW-GS)亚基功能的重要方法.本研究以软质小麦宁麦9号野生型及其单亚基缺失系为材料,探讨了HMW-GS缺失对籽粒品质性状、谷蛋白组分含量和加工品质的影响.在29份参试品系中,野生型有3个穗系,Glu-A1x、Glu-B1x、Glu-B1y、Glu-D1x和Glu-D1y缺失型分别有5、7、5、5和4份.野生型与缺失型,以及缺失型之间的蛋白质含量、湿面筋含量、籽粒硬度和溶剂保持力无显著差异.缺失型的谷蛋白/醇溶蛋白、高分量谷蛋白/低分子量谷蛋白含量比值低于野生型,其中Glu-B1x和Glu-D1x缺失型的比值显著低于野生型(P<0.05).缺失型的揉面仪峰值时间和8 min带宽变异范围分别为1.38~1.64 min和3.38%~3.98%,显著低于野生型的2.00 min和4.57%(P<0.05),以Glu-B1x和Glu-D1x缺失型表现最低.与野生型相比,缺失型的糖酥饼干直径均有增加,其中Glu-B1x、Glu-B1y和Glu-D1y缺失型饼干直径的增加达显著水平(P<0.05),而缺失型之间的差异不显著.在宁麦9号背景下,高分子量麦谷蛋白单亚基缺失弱化了面筋强度,改善了糖酥饼干加工品质,亚基敲除可能是进一步提高软质小麦加工品质的有效途径.%Gene knockout is an effective approach to investigate gene function of high-molecular-weight glutenin subunit (HMW-GS). In this study, we developed a set of single HMW-GS deletion lines of Ningmai 9 (soft wheat) to understand the effects of HMW-GS deletion on kernel quality, quantity of gluten protein fractions and processing quality. Among the 29 lines tested, three lines were wild type and the remaining were knockout mutants including Glu-A1x, Glu-B1x,Glu-B1y, Glu-D1x, and Glu-D1y deletion types of five, seven, five, five, and four lines, respectively. Compared with the wild type, the HMW-GS deletion lines had no significant difference in flour protein content, wet gluten content, kernel hardness, and solvent retention capacity. All the single HMW-GS deletion types decreased the ratios of glutenin-to-gliadin and HMW-GS-to-LMW-GS in quantity, and the decreases in Glu-B1x and Glu-D1x deletion types were significant atP< 0.05. In the wild type, mixograph peak time was 2.00 min and TIMEX width was 4.57%; whereas, those in the HMW-GS deletion lines were significantly lower (P < 0.05), varying from 1.38 min to 1.64 min and from 3.38% to 3.98%, respectively. Particularly, the Glu-B1x and Glu-D1x deletion lines showed the lowest mixograph peak time and TIMEX width. Although similar sugar snap cookie diameter was observed among the five deletion types, Glu-B1x, Glu-B1y, and Glu-D1y deletion types showed significantly higher cookie diameter than the wild type (P < 0.05). In this study, single deletion of HMW-GS weakened gluten strength and improved sugar snap cookie processing quality, indicating that HMW-GS knockout can be used to improve soft wheat quality.