Биологична активност на 20 изолата на ентомопатогенни гъби от род Beauveria

Abstract

Enzymes such as chitinase, proteinase and lipase are involved in the breakdown of insect cuticles. Their pathogenicity, virulence and specificity largely depend on the secretion of these enzymes by different microorganisms. Thus, the level of enzyme activity may also represent a diagnostic tool for selecting an effective biological control agent. In the present study, 20 different isolates of entomopathogenic fungi of the genus Beauveria were used and their lipolytic, chitinolytic and proteolytic activities were determined. Enzyme activities are assessed qualitatively according to the presence of a zone of lightening due to their degrading action and quantitatively expressed as a ratio between the zone of enzyme activity and the diameter of the colony. PCR analysis with gene-specific primers located in the sequence of the Beauveria bassiana chitinase - chitinase (chit1) gene (ACC AY145440) was also carried out. Amplifications of fragments with an expected length of 1225 bp were detected in the majority of Beauveria isolates studied. The studied isolates of the genus Beauveria differ in their lipolytic, proteolytic and chitin-degrading abilities. The highest total activity was found in four of them 336, 340, 487 and 501 and could be related to their virulence. The information on the enzymatic activities of the studied isolates will be necessary for the development of an efficient preparation for the biological control of the enemies.