Mycoinsecticide improvement based on Triatomine hydrocarbon degradation

N. PEDRINI, MP. JUÁREZ

Salvador de Bahia, Brasil

Workshop; Rhodnius Genome Workshop; 2007

Rhodnius Genome Consortium

Mycoinsecticide improvement based on Triatomine hydrocarbon degradation M. Patricia Juárez and Nicolás Pedrini Instituto de Investigaciones Bioquímicas de La Plata (CONICET-UNLP), Facultad de Ciencias Médicas, Calles 60 y 120, La Plata, 1900, Argentina. Tel: 54 221 482 4894 int 30 - Fax: 54 221 425 8988 e-mail: mjuarez@isis.unlp.edu.ar The insect cuticle is the first barrier against biological or chemical contact insecticides. A thin layer of lipids, mainly hydrocarbons, protects insects against lethal desiccation, and are proposed as a new target for triatomine control. Entomopathogenic fungi invade an insect host through the cuticle, and an obliged carbon source is required for a successful infection. We studied the effect of alkane-growth adaptation of the entomopathogenic fungus Beauveria bassiana on the ability to infect the Chagas disease vector Triatoma infestans. Two different strains of B. bassiana (Bb GHA and Bb 10) were both grown in agar plates and by solid state fermentation, under two different culture conditions. Fungal growth adaptation on an incubation medium containing insect-like hydrocarbons as the sole carbon source enhanced virulence parameters. Depending on the dose used, an increased mortality percentage (>50%) or a significant reduction (18%) in the time to kill T. infestans were observed, compared to controls grown in complete medium. These evidences suggest that the initial steps of infection might be improved by using a triatomine hydrocarbon mimic as the sole carbon source for fungal growth. Entomopathogenic fungi might be a new promising tool to help control these insect vectors in peridomestic environments, where the effectiveness of chemical insecticides is reduced.