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INFECTIVITY OF METARHIZIUM ANISOPLIAE IN GRASS SHRIMP EMBRYOS
Citation:
Genthner, F J., S S. Foss, AND P. S. Glas. INFECTIVITY OF METARHIZIUM ANISOPLIAE IN GRASS SHRIMP EMBRYOS. Presented at Annual Meeting of the Society for Invertebrate Pathology, Ithaca, NY, July 16, 1995 - July 21, 1996.
Impact/Purpose:
Presentation
Description:
Developing embryos of the estuarine grass shrimp, Palaemonetes pugio, were exposed to Metarhizium anisopliae conidiospores. Attachment of conidiospores was often followed by germination and outgrowth on embryo surface. Penetration of the embryonic envelopes by M. anisopliae allowed growth of the fungus with the embryo. Either the embryos died and were rapidly covered with mycelia, or infected embryos hatched and the larvae died shortly thereafter with fungal hyphae emerging from their exoskeletons. Delayed hatch was also observed. Ungerminated conidiospores possessed numerous hydrolytic enzymes on their surface. In all experiments the activity of several of these spore-associated enzymes was measured using the API ZYM(R) system (Analytab Products, Plainview, NY). A positive correlation was observed between virulence of M. anisopliae to P. pugio embryos and the activity of conidiospore-associated N-acetyl-B-D-glucosaminidase, EC 3.2.1.30, (NAGase). Conidiospores produced on agar plates containing glucose and yeast-extract as carbon sources possessed lower NAGase activity and were less virulent to shrimp embryos than were conidiospores produced on agar plates containing homogenized caterpillars as carbon source. Thus, M. anisopliae can be an invasive pathogen of grass shrimp embryos, and the growth substrates on which these spores develop can preadapt them for enhanced nontarget effects.