Genetic Analysis Of 7S Globulin Subunit And Lipoxygenases Double Lacking Traits In Soybean Seeds

7S globulin subunit is the main allergen of soybean,soybean seed;lipoxygenase is the essential soybean fishy smell produced.It is involved in the oxidation of unsaturated fatty acid in seed formation of small molecules hexenal,alcohol,ketone with fishy smell ingredients.Both of them are ingredients that must be removed in the process of soybean deep processing.Therefore,removing or reducing the content of 7S globulin and lipoxygenase has become one of the objectives of soybean quality improvement breeding.In this study,theα′-、α-、β-subunits of 7S globulin complete deletion of“1003-44”as the female parent,Lox-1,2,3 of lipoxygenase complete lacking of“SI0162”as the male parent.Using the method of artificial hybridization,we have harvested 21 seeds of F₁ generation.Then we have harvested 500 seeds of F₂ generation.Using ISDS-PAGE technology previously established in our team,we have identified the phenotypic traits of deletion of 7S globulinα′-、α-、β-subunits in F₁and F₂ generation seeds.Improving the method for detection of lipoxygenase deficiency,we have established a new method for identification of lipoxygenase isoenzymes in F₂ filial generation based on visual comparison analysis.We have identified the phenotypic traits of lipoxygenase isoenzymes in F₁ and F₂ filial generation by this method.The followings are the results:（1）The improved ISDS-PAGE technology in our team was used as an auxiliary test for the newly developed visual analysis method of soybean seeds lipoxygenase isoenzymes.It proved that this method has the advantages of rapid,simple and accurate identification in identifying lipoxygenase isoenzymes of F₂ seeds.This method is effective and feasible for the identification of lipoxygenase isoenzymes in F₂ filial generation.And it has important significance in breeding new soybean cultivars with high added value for food processing.（2）The results proved that all of 21 seeds from F₁ generation are theα′-、α-、β-subunits of 7S globulin complete deletion,while their lipoxygenase exists.In the F₂ separation generation,we only observed two phenotypic traits which are theα′-、α-、β-subunits of 7S globulin complete deletion（377）and wild type（121）.Using chi-square test,the result proved that in the 95%credibility level range,it was close to the theoretical number:null types:wild types=3:1.It is presumed that 7S globulin subunit lacking is a trait which is different from mutated mutant of 7S globulin subunit regulated by single recessive cgdef gene.It is a quality trait regulated by one pairs of dominant alleles.And it can be inherited steadily to the offspring.（3）There are 4 phenotypes observed after detecting lacking of Lipoxygenase（Lox-1,2,3）in F₂ seeds.They are Lox-1,2,3 wild type（282）,null type of Lox-3（96）,null type of Lox-1,2（93）and null type of Lox-1,2,3（27）.Using chi-square test for separation ratio of 4 phenotypes observed,the result proved that in the 95%credibility level range,it was close to the theoretical number:Lox-1,2,3 wild type:null type of Lox-3:null type of Lox-1,2:null type of Lox-1,2,3=9:3:3:1.It proved that lipoxygenase complete lacking is a quality trait controlled by 2recessive allele loci.And the genetic mechanisms of lipoxygenase and 7S globulin subunit complete lacking are not changed in the hybrid offspring after gene polymerization.The gene polymerization of this double null trait did not affect the normal growth and development of soybean.