A single base change at exon of Wx-A1 caused gene inactivation and starch properties modified in a wheat EMS mutant line.

Background Wheat is an essential source of starch. The GBSS or waxy genes are responsible for synthesizing amylose in cereals. This study identified a novel Wx-A1 null mutant line from an EMS-mutagenized population of common wheat cv. SM126 using sodium dodecyl sulfonate-polyacrylamide gel electrophoresis and agarose gel analyses. Results The alignment of the Wx-A1 gene sequences from the mutant and parental SM126 lines showed only one single nucleotide polymorphism (SNP) causing the appearance of a premature stop codon and Wx-A1 inactivation. The lack of Wx-A1 protein resulted in a decreased of amylose, total starch, and resistant starch. The starch morphology assessment revealed that starch from mutant seeds was more wrinkled, increasing its susceptibility to digestion. Regarding the starch thermodynamic properties, the gelatinization temperature was remarkably reduced in the mutant compared with that in the parental line SM126. The digestibility of native, gelatinized, and retrograded starches was analyzed for the mutant M4-627 and parental SM126 line. In the M4-627 line, rapidly digestible starch (RDS) contents were increased, whereas resistant starch (RS) was decreased in the three types of starch. Conclusion Waxy protein is essential for starch synthesis. The thermodynamic characteristics were declined in the Wx-A1 mutant line. The digestibility properties of starch were also affected. Therefore, the partial waxy mutant M3-627 might play a significant role in food improvement. Furthermore, it might be used to produce high-quality noodles. This article is protected by copyright. All rights reserved.