HEAT-SHOCK RESPONSE OF THE ENTOMOPATHOGENIC FUNGUS BEAUVERIA-BRONGNIARTII

The heat-shock response of five strains of the entomopathogenic fungus Beauveria brongniartii was studied using two-dimensional (2D) gel ele ctrophoresis. The fungal cells were heat shocked at 45 degrees C for 1 h and the total cellular protein was subjected to 2D gel electrophore sis. Proteins were separated in the first dimension using isoelectric focusing (pH range of 3.0-10) and in the second dimension by sodium do decyl sulphate - polyacrylamide gel electrophoresis. More than 150 pol ypeptides for each strain were visualized by silver staining and have been assigned individual numbers as polypeptide coordinates. Analysis of the polypeptide map obtained by 2D gels indicated three patterns; s everal unique heat-shock proteins (HSPs) were (i) induced, (ii) enhanc ed, or (iii) repressed. Some of the HSPs induced by 45 degrees C were unique for each of the strains tested. Identification of heat-inducibl e protein synthesis or repression has ramifications for field survival and performance of entomopathogenic fungi. As well, the HSPs can be u sed as ''signature proteins'' for identification pruposes and this rai ses the possibility of using HSPs as a diagnostic tool applicable to o ther pest control fungi.