Regulação da produção de subtilisinas pelo fungo entomopatogênico Beauveria bassiana

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Extracellular proteases have been shown to be virulence factors in fungal pathogenicity towards insects. We examined the production of extracellular subtilisinlike protease (Pr1) by Beauveria bassiana CG425, which is a fungus of interest for the control of the grasshopper Rhammatocerus schistocercoides. To access the role of Pr1 during infection of R. schistocercoides we analyzed its secretion during fungus growth in either in nitrate-medium or in cuticle-containing medium. An enhancing effect of cuticle on Pr1 production was observed. Real-time PCR assay revealed that the relative expression level of Pr1Bb in 12 h post-incubation in cuticle-containing medium was approximately 32-fold greater than in nitrate-containing medium. In minimal medium containing methionine (0.5%) a high level of Pr1 was also observed. In this culture condition the transcript levels of Pr1Bb was approximately 6-fold greater than in nitrate-containing medium. Moreover, in medium supplemented with grasshopper cuticle, the addition of methionine at a concentration of 0.75% repressed protease production and Pr1Bb expression. The results obtained have demonstrated that Pr1Bb gene is regulated by R. schistocercoides cuticle components and by the amino-acid methionine. In this study, we showed for the first time the transcription levels of B. bassiana Pr1 gene in the presence of R. schistocercoides cuticle, extending our knowledge about regulation of Pr1 production in this fungus.

ASSUNTO(S)

gafanhoto - controle biológico fungos entomopatogêncos grasshopper - biological control entomopathogenic fungi

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