Tuesday, 19 November 2002

This presentation is part of : Display Presentations, Section B. Physiology, Biochemistry, Toxicology, and Molecular Biology

Phylogenetic analysis of DlEPV genes

Pauline O. Lawrence, Entomology and Nematology, University of Florida, Entomology and Nematology, P. O. Box 110620, 970 Natural Area Drive, Gainesville, FL

The Diachasmimorpha longicaudata entomopoxvirus (DlEPV) from the poison gland of the female D. longicaudata parasitic wasp is injected with the wasp egg into larvae (hosts) of Anastrepha suspensa (Diptera:Tephritidae). DlEPV enhances survival of the egg by disrupting the encapsulation response of host hemocytes. The virus has a unipartite double stranded DNA genome of 250-300 kb and a biconcave central core with two lateral bodies, a characteristic of Group C (Diptera infecting) entomopoxviruses (EPVs). DlEPV is hypothesized to be a Group C EPV. The objectives were to (1) analyze DlEPV nucleotide and derived protein sequences to identify poxvirus motifs, (2) align the deduced proteins with those of other EPVs and estimate the phylogenetic position of DlEPV relative to other poxviruses. The Blastp, ClustalW, and Prosite programs revealed that the DlEPV ORFs are >60% A-T rich, contain poxvirus transcription initiation and termination sequences, and encode putative DNA helicase, NAD+-dependent DNA ligase, DNA polymerase, DNA-dependent RNA polymerase, and rifampicin resistance (RIF) proteins. These proteins are 40-78% homologous with those of AmEPV, MsEPV, two Group B EPVs, and vertebrate poxviruses. Phylogenetic analysis predicted that DlEPV arose from a different ancestral node from the Group B EPVs. There are no Group C EPV sequences for comparison. However, the virion size and morphology of DlEPV, its replication in a dipteran host, and different ancestral node from that of the Group B EPVs, support the hypothesis that DlEPV is most likely in the Group C Entomopoxvirinae.

Species 1: Hymenoptera Braconidae Diachasmimorpha longicaudata
Species 2: Diptera Tephritidae Anastrepha suspensa (Caribbean fruit fly)
Keywords: parasitic wasps, symbiotic entomopoxvirus

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