IDENTIFICACIÓN Y ANÁLISIS DE LOS GENES PRODUCTORES DE PROTEASAS TIPO SUBTILISINA Y TIPO TRIPSINA EN EL HONGO Metarhizium anisopliae COMO FACTORES DE VIRULENCIA PARA SU APLICACIÓN EN EL CONTROL BIOLÓGICO DE INSECTOS PLAGA

Abstract

In this work we used 4 strains of Metarhizium anisopliae (798, 6342, 6335 and 6347) provided by the Agricultural Research Service Collection of Entomopathogenic Fungi (ARSEF) which protease gene content and pathogenicity were evaluated. The gene content was.also correlated with the virulence caused by these strains to adults of the grass spittlebug and the beet armyworm larvae.. Only in strains 798, 6345 and 6347 were detected 8 of 11 subtilisin genes previously reported, similarly trypsin gene was also found. Only in the 6342 strain was not detected any of the mentioned genes. All the strains exhibited enzyme activity when growth in basal medium and basal medium supplemented with chitin. The strains with higher subtilisins type protease are 6347, 798 and 6345, while for the trypsin type strain is strain 6342. To determine the pathogenicity of the strains, bioassays were ocnducted in adults of the grass spittlebug collected in the region, and identified as Aeneolamia sp. and Prosapia sp., and larvae of the armyworm Spodoptera exigua. The results of bioassays showed a mortality of 50% for the grass spittlebug with strain 3019, 30% with strains 798, 6342, and 20% with strains 6345 and 6347. The mortality for the larvae of Spodoptera exigua is around 73.3% with strain 6342, 66.6% with the strain 6345, 60% with strain 798, 41% and 36% with strains 3019 and 6347. Finally we conclude that there is no correlation between the virulence and the presence of protease genes so that the virulence may be associated with other factors not determined in this work.