Expression of trypsin modulating oostatic factor (TMOF) in an entomopathogenic fungus increases its virulence towards <it>Anopheles gambiae</it> and reduces fecundity in the target mosquito

• Main Authors: Kamareddine Layla, Fan Yanhua, Osta Mike A, Keyhani Nemat O
• Format: Article
• Language: English
• Published: BMC 2013-01-01
• Series: Parasites & Vectors
• Subjects: Trypsin modulating oostatic factor; Biological control; <it>Beauveria bassiana</it>; <it>Anopheles gambiae</it>
• Online Access: http://www.parasitesandvectors.com/content/6/1/22

<p>Abstract</p> <p>Background</p> <p>Adult and larval mosquitoes regulate food digestion in their gut with trypsin modulating oostatic factor (TMOF), a decapeptide hormone synthesized by the ovaries and the neuroendocrine system. TMOF is currently being developed as a mosquitocide, however, delivery of the peptide to the mosquito remains a significant challenge. Entomopathogenic fungi offer a means for targeting mosquitoes with TMOF.</p> <p>Findings</p> <p>The efficacy of wild type and transgenic <it>Beauveria bassiana</it> strains expressing <it>Aedes aegypti</it> TMOF (<it>Bb</it>-Aa1) were evaluated against larvae and sugar- and blood-fed adult <it>Anopheles gambiae</it> mosquitoes using insect bioassays. <it>Bb-</it>Aa1 displayed increased virulence against larvae, and sugar and blood fed adult <it>A. gambiae</it> when compared to the wild type parent strain. Median lethal dose (LD₅₀) values decreased by ~20% for larvae, and ~40% for both sugar and blood-fed mosquitoes using <it>Bb</it>-Aa1 relative to the wild type parent. Median lethal time (LT₅₀) values were lower for blood-fed compared to sugar-fed mosquitoes in infections with both wild type and <it>Bb</it>-Aa1. However, infection using <it>Bb</it>-Aa1 resulted in 15% to 25% reduction in LT₅₀ values for sugar- and blood fed mosquitoes, and ~27% for larvae, respectively, relative to the wild type parent. In addition, infection with <it>Bb</it>-Aa1 resulted in a dramatic reduction in fecundity of the target mosquitoes.</p> <p>Conclusions</p> <p><it>B. bassiana</it> expressing <it>Ae. aegypti</it> TMOF exhibited increased virulence against <it>A. gambiae</it> compared to the wild type strain. These data expand the range and utility of entomopathogenic fungi expressing mosquito-specific molecules to improve their biological control activities against mosquito vectors of disease.</p>