| Congresso Brasileiro de Microbiologia 2023 | Resumo: 27-1 | ||||
Resumo:The insect-pathogenic fungus Metarhizium robertsii responds to several priming conditions, such as white and blue light, hypoxia, biotic stress caused by Trichoderma atroviride antagonism, heat shock, nutritive stress, osmotic and oxidative stress, acid and alkaline stress, and salicylic-acid, and as a result the fungus become more tolerant to other stress conditions. On the other hand, conidia produced on insect cadavers are less tolerant to UV-B radiation. These stress priming conditions induce protein sensors and signaling pathways that link the external physical or chemical inputs to cellular response.However, little is known about the phenotypic effects caused by magnetic and electric fields on fungal mycelial growth and its priming responsiveness on conidial tolerance to different stress conditions. In this study, conidia of the insect-pathogenic fungus Metarhizium robertsii were produced on 1) potato dextrose agar medium (PDA = control), 2) under nutritional stress on minimal medium (MM), and on PDA medium under 3) magnetic field (MF) and 4) electric field (EF). All four treatments were incubated in the dark. The tolerances of conidia produced on these conditions were evaluated in relation to oxidative and osmotic stress, heat, and UV-B radiation. Apparently, the cultures of the fungus grown on the PDA medium under magnetic and electric fields were similar to the fungus grown on the control PDA medium; however, the three treatments produced more conidia than the fungus produced on the minimal medium. Metarhizium robertsii conidia produced under magnetic and electric fields were more tolerant to oxidative and osmotic stress, heat, and UV-B radiation. Both treatments, MF and EF, produced conidia with similar tolerances to all stress conditions, except for osmotic stress where conidia from MF were more tolerant than conidia from EF. On the other hand, conidia produced under magnetic and electric fields were less tolerant than conidia produced on minimal medium which causes nutritional stress. In conclusion both magnetic and electric field induced priming on Metarhizium robertsii but not at the same level than nutritive stress. Palavras-chave: Entomopathogenic fungi, solar radiation, stress tolerance, magnetic field, electric field Agência de fomento:CNPq | |||||