Evidence of cAMP involvement in cellobiohydrolase expression and secretion by Trichoderma reesei in presence of the inducer sophorose

• Grant number: 15/20374-8
• Support type: Regular Research Grants - Publications - Scientific article
• Duration: January 01, 2016 - June 30, 2016
• Field of knowledge: Biological Sciences - Microbiology
• Principal Investigator: Roberto Do Nascimento Silva
• Grantee: Roberto Do Nascimento Silva
• Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Background: The signaling second messenger cyclic AMP (cAMP) regulates many aspects of cellular function in allorganisms. Previous studies have suggested a role for cAMP in the regulation of gene expression of cellulolytic enzymes inTrichoderma reesei (anamorph of Hypocrea jecorina).Methods: The effects of cAMP in T. reesei were analyzed through both activity and expression of cellulase, intracellularcAMP level measurement, western blotting, indirect immunofluorescence and confocal microscopy.Results: To elucidate the involvement of cAMP in the cellulase expression, we analyzed the growth of the mutant strain”acy1 and its parental strain QM9414 in the presence of the inducers cellulose, cellobiose, lactose, or sophorose, and therepressor glucose. Our results indicated that cAMP regulates the expression of cellulase in a carbon source-dependentmanner. The expression cel7a, and cel6a genes was higher in the presence of sophorose than in the presence of cellulose,lactose, cellobiose, or glucose. Moreover, intracellular levels of cAMP were up to four times higher in the presence ofsophorose compared to other carbon sources. Concomitantly, our immunofluorescence microscopy and western blot datasuggest that in the presence of sophorose, cAMP may regulate secretion of cellulolytic enzymes in T. reesei.Conclusions: These results allow us to better understand the role of cAMP and expand our knowledge on the signaltransduction pathways involved in the regulation of cellulase expression in T. reesei. Finally, our data may help developnew strategies to improve the expression of cel7a and cel6a genes, and therefore, favor their application in severalbiotechnology fields. (AU)