Caracterização de proteases secretadas por Sclerotinia sclerotiorum

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Universidade Federal de Goiás


Sclerotinia sclerotiorum is a fungus that infects many economically important plants. The production of oxalic acid, decreased the pH of the medium and the secretion of hydrolytic enzymes such as proteases, are determining factors for the infection of this pathogen. Proteases secreted by the fungus S. sclerotiorum degrade the cell wall proteins of the host and antifungal proteins secreted by the plant during the invasion. This study aimed to characterize molecular and biochemical proteases in S. sclerotiorum, during the invasion in bean plants (Phasheolus vulgaris L.) and in culture medium supplemented with pectin, the wall of bean extract and glucose as carbon sources. The secretion of these proteases was detected by enzymatic assays with specific inhibitors and buffered media at different pH. The level of expression of genes encoding for the protease aspartyl (aspS) and acid protease (acp1), respectively, were detected by qRT-PCR technique. Enzyme activity was detected in all sources of carbon, but higher levels were found when pectin was used as the sole carbon source. Tests with different proteolytic inhibitors showed that Pepstatin A specific inhibitor for aspartyl protease-inhibitor that has been the greatest action in culture media, indicating the probable secretion of aspartyl proteases. Of qRT-PCR experiments showed that the expression of genes aspS and acp1 was increased in S. sclerotiorum both in culture medium supplemented with pectin or extract of the cell wall of bean, as during the infection in bean seedlings. These results suggest that the fungus secret proteases during the infection of the host plant. And the different carbon sources evaluated, similar to components of the cell wall of host plants, are effective for the induction of gene expression (acp1 and aspS) in S. sclerotiorum. Thus, the proteases have been considered an important virulence factor in increasing the efficiency of fungal attack in plants.



ALVES, E. B. Caracterização de proteases secretadas por Sclerotinia sclerotiorum. 2019. 50 f. Dissertação (Mestrado em Ciências Biológicas) - Universidade Federal de Goiás, Goiânia, 2009.