Expression of Genes Encoding Globulin and Prolamin Storage Proteins in Kernels of Illinois Long Term Chemical Selection Strains

Abstract

Seed storage protein genes represent an interesting model system to study the structure and function of nuclear genes in higher plants. The Illinois long term chemical selection strains of maize (Zea mays L.) were used in the present study with an objective to investigate the expression of genes encoding seed storage proteins. Analysis of the endosperm proteins by SDS‐PAGE (sodium dodecyl sulfate‐polyacrylamide gel electrophoresis) indicated a general trend in the level of certain polypeptides in different protein selection strains. As percent protein increased as a function of selection, the level of α‐zeins also increased. Embryo protein profiles of IHP (Illinois High Protein) and ILP (Illinois Low Protein) analyzed by SDS‐PAGE and immunoblot analysis indicated that these populations lack detectable globulinl (GLB1) protein. However, PCR (polymerase chain reaction) amplification of DNA from HIP plants and subsequent Southern hybridization with a radiolabeled oligonucleotide probe specific for glb1 intron2 confirmed that the glb1 gene is present in the IHP population. The glbl gene expression patterns were analyzed using embryos from different developmental stages of maize kernels of both IHP and ILP strains. Levels of glbl transcripts were 10‐fold lower in IHP and 30‐fold lower in ILP at 26 DAP as compared with standard functional alleles from maize inbred lines W64A and Va26. In conclusion, we have analyzed a null variant of globulin1 protein in Illinois long term chemical selection strains which would serve as tool to study the molecular basis of gene regulation.