Genetic Variability among Brazilian Isolates of the Entomopathogenic Fungus Metarhizium anisopliae

• Published in: Journal of invertebrate pathology 1995, Vol.65 (2), p.206-210
• Main Authors: Tigano-Milani, Myrian S., Gomes, Ana Cristina M.M., Sobral, Bruno W.S.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biological control; Control; Fundamental and applied biological sciences. Psychology; Metarhizium anisopliae; Metarhizium flavoviride; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates
• ISSN: 0022-2011; 1096-0805
• DOI: 10.1006/jipa.1995.1031

Entomopathogenic fungi have been proposed as biocontrol agents against diverse insect pests in agriculture. In particular, Metarhizium anisopliae has been tested against a wide range of hosts in different geographical regions. In northeastern Brazil, M. anisopliae has been applied in sugarcane fields to control Mahanarva posticata. In Central Brazil, studies have been undertaken to use this fungus to control the pasture spittle bug, Deois flavopicta (Homoptera:Cercopidae). Natural incidence of M. anisopliae has been observed in populations of nymphs and adults of this insect. For biological control it is necessary to understand the parameters that govern the efficacy and persistence of an introduced isolate of M. anisopliae. Positive identification of the introduced isolate will require characterization of the indigenous populations and comparison to the introduced isolate. These can be accomplished with genetic markers. Genetic distances calculated from isozyme phenotypes have shown that Brazilian M. anisopliae isolates are composed of rare and common genotypic classes within what is morphologically classified as M. anisopliae var. anisopliae. However, the same studies showed that other isolates classified as of the same taxon, obtained from different countries and diverse hosts, show a high level of variability. Recently, the arbitrarily primed polymerase chain reaction (PCR), also known as random amplified polymorphic DNA (RAPD) markers, was used to study genetic variability of M. anisopliae isolates. These studies revealed a high level of intraspecific variability within this morphologically determinate species, even among isolates from the same geographical area in Australia. In this study we report the use of arbitrarily primed PCR markers to study genetic relationships among M. anisopliae isolates from Brazilian soil samples or specific insect hosts. Thirty-three isolates of M. anisopliae and two isolates of M. flavoviridae were studied.