Genomic and host range studies of Maruca vitrata nucleopolyhedrovirus

Abstract

The complete genome of the Maruca vitrata nucleopolyhedrovirus (MaviNPV) isolated from the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), was sequenced. It was found to be 111 953 bp in length, with an overall 39 % G+C content, and contained 126 open reading frames (ORFs) encoding predicted proteins of over 50 aa. The gene content and gene order of MaviNPV have the highest similarity to those of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and their shared homologous genes are 100 % collinear. In fact, MaviNPV seems to be a mini-AcMNPV that is native to Taiwan and possesses a smaller genome with fewer auxiliary genes than the AcMNPV type species. Except for one ORF (Mv74), all of the MaviNPV ORFs have homologues in the AcMNPV genome. MaviNPV is the first lepidopteranspecific baculovirus to lack homologues of vfgf and odv-e66. In addition, MaviNPV lacks the baculovirus repeat ORF (bro) gene that corresponds to AcMNPV ORF2. Five homologous regions (hrs) were located within the MaviNPV genome, and these contained a total of 44 imperfect palindromes. Phylogenetic analysis of the whole genome revealed that MaviNPV was separated from the common ancestor of AcMNPV and Bombyx mori nucleopolyhedrovirus before these two viral species diverged from each other. Moreover, replication of MaviNPV in several cell lines and an egfp-MaviNPV infection assay revealed that IPLB-LD-652Y cells are only partially permissive to MaviNPV, which supports our conclusion that MaviNPV is a distinct species of the group I lepidopteran NPVs.

Conserved baculoviral ORFs 10 and 14 from Bombyx mori multiple nucleopolyhedrovirus

“…It also had an identity of 88% with folding protein or F protein of PxMNPV (Harrison and Lynn, 2007), and with a folding protein of A. californica as well (Ayres et al, 1994). However, an identity of 84% was observed with a fusion protein of RoMNPV (Harrison and Bonning, 2003), whereas a 65% identity to MvMNPV was detected (Chen et al, 2008).…”

“…The analysis of ORF14 nucleotide sequence revealed that the sequence of MNPV subgroup of B. mori (BmMNPV) had identity equivalent to 99, 94, 93, 89, 79%, respectively, with: BmNPV genome, isolate T3 (Gomi et al, 1999); AcMNPV genome, clone C6 (Ayres et al, 1994); PxMNPV genome, isolate CL3 (Harrison and Lynn, 2007); RoMNPV genome (Harrison and Bonning, 2003), and MvMNPV genome (Chen et al, 2008). …”

Baculovirus genes affecting host function

“…The recently completed genome sequence of Maruca vitrata NPV (MaviNPV) lacks vfgf (Chen et al 2008). Assays of AcMNPV and BmNPV vFGF protein function show properties consistent with those of a growth factor.…”

Morphology and genome of Euproctis pseudoconspersa nucleopolyhedrovirus

“…Among these genes, alk-exo was conserved in all baculovirus and fgf and was conserved in all lepidopteran baculoviruses [20]. Actin rearrangement-inducing factor-1 (arif-1) and ptp-1 was another two auxiliary genes, but absent in EupsNPV [26]. Homologous repeat sequences (hrs)…”