PROTEIN-SYNTHESIS AND GENE-EXPRESSION DURING APPRESSORIUM FORMATION IN GLOMERELLA-MAGNA

While conidial germlings of the watermelon anthracnose fungus,Glomerella magna, differentiate to form appressoria on surfaces like glass or polystyrene to which they can attach, they grow as simple germ tubes on an agar surface. We have exploited this property to study differential protein synthesis and gene expression during appressorium development. Polyacrylamide gel electrophoretic analyses showed that the synthesis of at least nine polypeptides was upshifted during the early stages of appressorium development. Using developmentally specific probes prepared by cascade hybridization, we obtained 59 specific clones representing 11 classes. RNA blot analyses showed that transcripts of these genes were most abundant in differentiated germlings, while they either were not detected or were at low levels in nondifferentiated germlings. © 1990 Academic Press, Inc.