Liu Guangxiao, Gao Yujiao, Wang Huadun, Wang Yonggang, Chen Jianmin, Zhang Pingping, Ma Hongxiang
Jiangsu Co-innovation Center for Modern Production Technology of Grain Crops/Jiangsu Key Lab of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China.
Co-innovation Center for Modern Crop Production Co-sponsored by Province and Ministry, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Front Plant Sci. 2022 May 12;13:835164. doi: 10.3389/fpls.2022.835164. eCollection 2022.
The area between middle and lower reaches of the Yangtze River is the largest region for soft wheat production in China. In soft wheat breeding, the lack of germplasm with desirable quality for end-use products is a barrier. Ningmai9 is the main variety of soft wheat planted in this area. To create germplasm with better quality and yield potential than Ningmai9, mutants of HMW-GSs in Ningmai9 induced by ethylmethanesulfonate (EMS) were obtained. SDS-PAGE showed that two mutants, md10 and md11, were HMW-GS 1Dy deletions. DNA sequencing confirmed that one mutation was caused by a C/T substitution, resulting in the change of CAA encoding glutamine into the termination codon TAA, and another mutation was due to a G/A substitution in the central repetitive domain of the coding region, causing TGG encoding tryptophan to become the termination codon TGA. The premature termination codon of the gene affected the expression of and kept the mRNA at a lower transcription level during the kernel development stage in comparison with the wild type. HMW-GS 1Dy12 deletion mutants decreased the content of HMW-GSs and glutenin macropolymers, mixograph envelope peak time and TIMEX width, water solvent retention capacity (WSRC), and lactic acid solvent retention capacity (LASRC). In the HMW-GS 1Dy12 deletion lines, the sugar-snap cookie diameter was 8.70-8.74 cm, which was significantly larger than that in the wild type of 8.0 cm. There were no significant differences in spike number, kernel number, thousand kernel weight, and yield between the deletion lines and wild type. Overall, the study indicated that the knockout of the gene induced by EMS is an effective way to improve wheat quality, and deletion mutants of HMW-GS 1Dy12 decrease gluten strength and increase sugar snap cookie diameter without yield penalty in Ningmai9 wheat.
长江中下游地区是中国软质小麦的最大产区。在软质小麦育种中，缺乏具有理想终产品品质的种质是一个障碍。宁麦9是该地区种植的主要软质小麦品种。为了创制出品质和产量潜力优于宁麦9的种质，获得了用甲基磺酸乙酯（EMS）诱变宁麦9的高分子量谷蛋白亚基（HMW-GSs）突变体。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）显示，两个突变体md10和md11是HMW-GS 1Dy缺失突变体。DNA测序证实，一个突变是由C/T替换引起的，导致编码谷氨酰胺的CAA变为终止密码子TAA，另一个突变是由于编码区中央重复结构域中的G/A替换，使编码色氨酸的TGG变为终止密码子TGA。该基因的提前终止密码子影响了其表达，并使mRNA在籽粒发育阶段与野生型相比保持在较低的转录水平。HMW-GS 1Dy12缺失突变体降低了HMW-GSs和谷蛋白大聚合体的含量、揉混仪包络峰时间和TIMEX宽度、水溶剂保持能力（WSRC）以及乳酸溶剂保持能力（LASRC）。在HMW-GS 1Dy12缺失系中，糖脆饼干直径为8.70 - 8.74厘米，显著大于野生型的8.0厘米。缺失系与野生型在穗数、粒数、千粒重和产量方面没有显著差异。总体而言，该研究表明EMS诱变敲除该基因是改善小麦品质的有效途径，HMW-GS 1Dy12缺失突变体降低了宁麦9小麦的面筋强度并增加了糖脆饼干直径，且不影响产量。
