EXPRESSION OF GENES ENCODING GLOBULIN AND PROLAMIN STORAGE PROTEINS IN KERNELS OF ILLINOIS LONG-TERM CHEMICAL SELECTION STRAINS

Seed storage protein genes represent an interesting model system to st udy the structure and function of nuclear genes in higher plants. The Illinois long term chemical selection strains of maize (Zea mays L.) w ere used in the present study with an objective to investigate the exp ression of genes encoding seed storage proteins. Analysis of the endos perm proteins by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel e lectrophoresis) indicated a general trend in the level of certain poly peptides in different protein selection strains, As percent protein in creased as a function of selection, the level of alpha-zeins also incr eased. Embryo protein profiles of IHP (Illinois High Protein) and ILP (Illinois Low Protein) analyzed by SDS-PAGE and immunoblot analysis in dicated that these populations lack detectable globulin1 (GLB1) protei n. However, PCR (polymerase chain reaction) amplification of DNA from IHP plants and subsequent Southern hybridization with a radiolabeled o ligonucleotide probe specific for glb1 intron2 confirmed that the glb1 gene is present in the MP population. The glb1 gene expression patter ns were analyzed using embryos from different developmental stages of maize kernels of both MP and ILP strains. Levels of glb1 transcripts w ere 10-fold lower in IHP and 30-fold lower in ILP at 26 DAP as compare d with standard functional alleles from maize inbred lines W64A and Va 26. Tn conclusion, we have analyzed a null variant of globulin1 protei n in Illinois long term chemical selection strains which would serve a s tool to study the molecular basis of gene regulation.