The study of intracellular and secreted high-molecular-weight protease(s) of Trichoderma spp., and their responses to conidiation stimuli

We continued the study of high-molecular-weight proteases (HMWP) using several strains of the genus Trichoderma, and other filamentous fungi (Botrytis cinerea, Aspergillus niger, Fusarium culmorum and Penicillium purpurogenum) in this work. We found that five Trichoderma strains secreted HMWP into the media after induction with bovine serum albumin. B. cinerea and F. culmorum secreted proteases without the presence of inducer, while A. niger or P. purpurogenum did not secrete proteolytic activity (PA). The activity of HMWP in Trichoderma spp. represents the predominant part of cellular PA, according to zymogram patterns. This observation allowed the study of its physiological role(s) independent from the secretion. In the study of conidiation, we found that the illumination significantly stimulates the PA in Trichoderma strains. In T. atroviride IMI 206040 strain, we demonstrated that this stimulation is dependent on the BLR1 and BLR2 receptors. No stimulation of PA was observed when the mechanical injury was used as an elicitor of conidiation. Compounds used as inhibitors or activators of conidiation exerted no congruent effects on both PA and conidiation. These results do not favour the direct role of HMWP in the conidiation. Probably, its activity may be involved in the process of the activation of metabolism during vegetative growth, differentiation, and aging-related processes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author