Soybean storage protein genes: Gene structure and organization
Abstract
Glycinin, together with $\beta$-conglycinin, are the major storage proteins of soybean (Glycine max L., Merr). To provide information about the glycinin subunits, the structures of Gy$\sb3$ and Gy$\sb5$ were determined by DNA sequence analysis and S1 protection experiments. The results showed that these two genes had four exons and three introns like the other three glycinin genes. The promoter regions in all of these genes were highly conserved. The data also revealed that there was a highly variable region in the glycinin protein. It was suggested that the hypervariable region might be an ideal site into which modifications can be directed to improve nutritional quality of the protein. During the course of these experiments an apparent pseudogene for Gy$\sb3$ glycinin gene was discovered in the cultivar Forrest. The aberrant allele (gy$\sb3$) was found to lack the 5$\sp\prime$-end of the gene immediately upstream from the 3$\sp\prime$ junction of the second intron. The molecular basis for this allele has been determined by (1) comparing the nucleotide sequences of the normal allele and aberrant allele; (2) conventional segregation analysis of the restriction fragment length polymorphism markers for various parts of the aberrant allele; and (3) restriction site mapping and DNA sequencing of the junction points in the Forrest and Raiden genomes. The available data indicate that a chromosome was responsible. The inheritance and organization of the glycinin genes was also investigated. To accomplish this, DNA restriction fragment length polymorphisms of glycinin genes, together with SDS-polyacrylamide gel electrophoresis of the proteins, were used. The results indicated that the five glycinin genes were found in four genetic loci that segregated independently. None of the glycinin genes were linked to the known phenotypic marker genes t (pubescence color), w$\sb1$ (flower color), i (pigment distribution on seed coat), r (seed color), and l$\sb2$ (pod color).
Degree
Ph.D.
Advisors
Nielsen, Purdue University.
Subject Area
Biology
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