The Genetics of Soybean Seed Urease (Isozymes, Clycine Max, Transcription)

79 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.The objectives were (i) to study the inheritance of the soybean seed urease isozymes, (ii) to determine the cause of the isozyme polymorphism and (iii) to study the inheritance of a soybean seed urease null.Reciprocal crosses between cultivars homozygous for the electrophoretic slow and fast forms of seed urease were made. The results indicate that the fast and slow variants are inherited as codominant alleles.Before begining a study to determine the source of the polymorphism between the fast and slow forms of seed urease, a speedier means of purifying urease is necessary. Seed urease was adsorbed to chloramphenicol-caproate substituted agarose. The enzyme was eluted when the ionic strength of the solution was increased and the pH decreased. Preliminary experiments show a thousand-fold purification of urease with a low yield.The soybean seed urease null phenotype was previously described as lacking seed urease activity and antigen. Null lines behave similarly when crossed to cultivars homozygous for the slow or fast alleles of seed urease: the F(,1) seed from crosses of urease expressing cultivars with nulls express the urease allele of the cultivar and a 3:1 segregation for the presence and absence of urease is observed in progeny from F(,1) and heterozygous F(,2) plants. Examination of F(,2) and F(,3) urease positive seed revealed that this seed from fast x null crosses are all phenotypically urease fast, while the same seed from slow x null crosses shows a segregation of one seed that contains a fast urease either exclusively or in a heterozygous state with the slow isozyme for every 69 phenotypic slows. The data indicates that the urease null is caused by a cis-acting, epistatic allele linked to, but distinct from the isozyme locus. The urease nulls all carry an unexpressed fast form of seed urease.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD