Crescimento do fungo Metarhizium Robertsii sob campo magnético e campo elétrico altera tolerância de conídios a estresses

Abstract

Little is known about the phenotypic effects caused by magnetic and electric fields on fungal mycelial growth and on conidial tolerance to different stress conditions. In this study, conidia of the entomopathogenic fungus Metarhizium robertsii were produced on potato, dextrose, agar medium (PDA = control), under nutritional stress on minimal medium, and on PDA medium in a magnetic field and an electric field. The tolerance of conidia produced on minimal medium, PDA (control), magnetic field, and electric field were evaluated in relation to UV-B radiation, heat, and osmotic stress. The phenotypic results on the tolerance to different stress conditions provided important information about the effects of the magnetic and electric fields during mycelial growth on the conidial stress tolerance of insect pathogens. The primary hypothesis is that exposure to a magnetic field during mycelial growth increases conidia tolerance to one or more environmental stresses in fungi. Apparently, the fungus grown on the PDA medium in magnetic and electric fields were the same as the fungus grown on the control PDA medium; however, the three treatments produced more conidia than the fungus produced on the minimal medium. On the one hand, M. robertsii conidia produced in magnetic and electric fields were more tolerant to heat stress and UV-B radiation stress, but not to osmotic stress. On the other hand, the fungus produced in magnetic and electric fields were less tolerant than the fungus produced on the minimal medium that causes nutritional stress.