Effect Of ω5-2 Gliadin On The Processing Quality Of Wheat

The processing quality of wheat is mainly determined by the content and composition of seed storage protein.Wheat seed storage protein is one of the main protein sources for human beings.According to the difference in solubility,wheat seed storage protein can be divided into two types: i.e.glutenin and gliadin,which accounts for about 85% of the total seed protein.Glutenin provides gluten elasticity and gliadin gives gluten ductility,and the two determine the processing quality of wheat.Here,a knockout mutant(3-3)and a faster mobility mutant(S1-44)for a protein band belonging to the ω5-gliadin zone were obtained from the EMS mutagenesis group of common wheat cultivar “Shu Mai 482”,by using sodium alkyl sulfonate polyacrylamide gel electrophoresis(SDS-PAGE).We have tentatively named it ω5-2 gliadin.Then the mutants were backcrossed with Shu Mai 482,and the hybrid progenies were used for measuring the parameters of processing quality.The main results are as follows: 1.SDS-PAGE and mass spectrometry analysisCompared with Shu Mai 482,the mutant “3-3” lost the second band of the ω5 gliadin region,and the second band of the ω5 gliadin in mutant “S1-44” shown accelerated mobility in SDS-PAGE.To determine whether the targeted protein band belongs to ω5 gliadin,the second band was cut from SDS-PAGE and used for mass spectrometry detection.As a result,globulin,γ-gliadin,enzymes and some unknown proteins were identified,while no ω-gliadin was found.Since ω-gliadin is rich in repetitive sequence and is not easy to be cut by enzymes,it is necessary to further determine the type of the protein band by other methods.2.Comparison of processing quality parametersThe thousand-grain weight,bulk weight,flour protein content,dry/wet gluten content,gluten index,Zeleny sedimentation value and farinograph pa rameters of the two mutants and their control were compared,respectively.There was significant difference between 3-3 and its control in the thousand-grain weight.And significnat difference was identified between the gluten index between S1-44 and its control.However,no significant difference was observed in bread volume when comparing the mutants and their corresponding control.Therefore,we postulated that ω5-2 protein band had little effect on wheat processing quality.