Tolerância ao estresse de conídios de Metarhizium Robertsii produzidos em meio suplementado com Sulfato de zinco

Abstract

Fungi for industrial and agricultural uses are subject to a variety of physical and chemical insults, collectively referred to as stresses. The fungal response to stress conditions may be due to growth and metabolism impairments and it is important to understand the physiology of stress responses to alleviate detrimental influences when applying the fungus in the field for insect control. The present study aims to evaluate the physiological and morphological effects of zinc sulfate on the entomopathogenic fungi Metarhizium robertsii, as well as the mycelial growth of this fungus, and its tolerance to the stresses of conidia produced in media supplemented with zinc under UV radiation, stress osmotic (potassium chloride) and heat. Mycelium radial growth showed that this salt does not influence the growth of the studied fungus. With regard to tolerance to UV radiation, it was observed that the germination of conidia produced at a concentration of 1.5 g/l obtained similar tolerance to conidia produced under normal conditions, thus being more tolerant than those produced at concentrations 0.5, 1.0 and 2.0g /l. This finding is similarly observed with regard to tolerance to the Osmotic Stress condition. Germination of M. robertsii conidia supplemented with zinc sulfate induced greater heat tolerance when compared to other treatments.