Genomic sequencing and analyses of Lymantria xylina multiple nucleopolyhedrovirus

Abstract

BackgroundOutbreaks of the casuarina moth, Lymantria xylina Swinehoe (Lepidoptera: Lymantriidae), which is a very important forest pest in Taiwan, have occurred every five to 10 years. This moth has expanded its range of host plants to include more than 65 species of broadleaf trees. LyxyMNPV (L. xylina multiple nucleopolyhedrovirus) is highly virulent to the casuarina moth and has been investigated as a possible biopesticide for controlling this moth. LdMNPV-like virus has also been isolated from Lymantria xylina larvae but LyxyMNPV was more virulent than LdMNPV-like virus both in NTU-LY and IPLB-LD-652Y cell lines. To better understand LyxyMNPV, the nucleotide sequence of the LyxyMNPV DNA genome was determined and analysed.ResultsThe genome of LyxyMNPV consists of 156,344 bases, has a G+C content of 53.4% and contains 157 putative open reading frames (ORFs). The gene content and gene order of LyxyMNPV were similar to those of LdMNPV, with 151 ORFs identified as homologous to those reported in the LdMNPV genome. Two genes (Lyxy49 and Lyxy123) were homologous to other baculoviruses, and four unique LyxyMNPV ORFs (Lyxy11, Lyxy19, Lyxy130 and Lyxy131) were identified in the LyxyMNPV genome, including a gag-like gene that was not reported in baculoviruses. LdMNPV contains 23 ORFs that are absent in LyxyMNPV. Readily identifiable homologues of the gene host range factor-1 (hrf-1), which appears to be involved in the susceptibility of L. dispar to NPV infection, were not present in LyxyMNPV. Additionally, two putative odv-e27 homologues were identified in LyxyMNPV. The LyxyMNPV genome encoded 14 bro genes compared with 16 in LdMNPV, which occupied more than 8% of the LyxyMNPV genome. Thirteen homologous regions (hrs) were identified containing 48 repeated sequences composed of 30-bp imperfect palindromes. However, they differed in the relative positions, number of repeats and orientation in the genome compared to LdMNPV.ConclusionThe gene parity plot analysis, percent identity of the gene homologues and a phylogenetic analysis suggested that LyxyMNPV is a Group II NPV that is most closely related to LdMNPV but with a highly distinct genomic organisation.

Identification of a Novel Apoptosis Suppressor Gene from the Baculovirus Lymantria dispar Multicapsid Nucleopolyhedrovirus

“…4B and C), indicating that Ld109 was capable of suppressing apoptosis and caspase-3-like A database search revealed that ld109 homologues were found in nine NPVs, four granuloviruses, and one poxvirus. The Ld109 protein shared amino acid sequence identities ranging from 23.3% with fowlpox virus FPV217 (1) to 86.0% with Lymantria xylina MNPV ORF109 (22). A domain search revealed no characteristic domains of the Ld109 protein that were linked to possible functions, and functional analyses have not been conducted for any of these Ld109 homologues.…”

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“…Later, the phylogenetics of NPVs were generated with other conserved genes, www.scienceasia.org for example lef-2 33 , lef-8, lef-9 34,35 , and ecdysteroid UBP-glycosyl transferase (egt) 4 . Recently, many phylogenetics of NPVs have been established by means of the combination of several conserved gene sequences and whole genome sequences 7,36,37 . These phylogenetic trees were suggested to be more acceptable than those constructed by a single gene.…”

“…The remaining 4 unique amino acid positions were located in the C-terminal region of IE-1. The C-terminal region contains a domain required for inhibitory and DNAbinding activities 37 . Only one of these 4 unique amino acid positions was in a putative single-stranded-DNAbinding motif that may be involved in DNA binding 12 .…”

“…Eight of these 12 conserved amino acids were located in the N-terminal part of the IE-1 protein. The N-terminal region of the IE-1 protein contains an acidic domain that is essential for the viral transactivational activity [37][38][39][40] . The remaining 4 unique amino acid positions were located in the C-terminal region of IE-1.…”

Sequenciamento do baculovírus que infecta a broca-da-cana-de-açúcar Diatraea saccharalis.

“…helicase, que desenrola as fitas de DNA; dna polimerase, polimeriza a nova fita de DNA; lef-3, que produz uma proteína ligante (estabilizadora) à fita simples de DNA, KUZIO et al, 1999;LI et al, 2002a;NAI et al, 2010). Durante a replicação, as proteínas ALK-EXO (nucleases alcalinas), LEF-3 e VLF-1 atuam no processo de recombinação, permitindo montar mais rapidamente os genomas virais .…”