Prelecionista: Jessiane dos Santos Corrêa
Orientador: Lucas Abreu
Data: Terça, 24/06/25, às 16h
Local: Auditório do DFP

Resumo: Solar radiation, although essential for life on Earth, represents a constant source of stress for exposed microorganisms, such as phytopathogenic fungi that colonize aerial plant tissues. Among the most harmful effects of ultraviolet (UV) radiation are the formation of pyrimidine dimers in DNA, which can lead to mutations, and the accumulation of reactive oxygen species (ROS). To survive and maintain their infective capacity, phytopathogens have developed a variety of adaptive strategies. This seminar will address the main protective mechanisms against UV radiation, with an emphasis on the production of photoprotective pigments such as melanin, which serves as a first line of defense capable of scavenging ROS and absorbing radiation photons. Experimental evidence from different fungal genera will be presented, comparing the responses of melanized fungi with strategies adopted by non-melanized fungi, such as the secretion of mucilage rich in protective compounds, as observed in Colletotrichum species. Once UV-induced cellular damage is established, we will highlight the activation of DNA repair mechanisms, focusing on photoreactivation mediated by photolyases,enzymes capable of directly reversing DNA lesions. Molecular aspects of the expression and regulation of genes associated with this mechanism will be discussed, as well as the influence of other regions of the solar spectrum, such as visible light, on its activation.