Characterization of a granulosis virus from the castor semilooper, Achaea janata L

Molecular and in Silico Characterization of Achaea janata Granulovirus Granulin Gene

Achaea janata granulovirus (AcjaGV), an insect virus belonging to Baculoviridae, infects semilooper, a widely distributed defoliating pest on castor beans (Ricinus communis L.) and several other plant hosts in India. The propagation and purification of the Hyderabad isolate AcjaGV were performed, granulin gene from this isolate was amplified, cloned and sequenced, and its homology with other known granulin genes was assessed. The 753-bp granulin ORF of AcjaGV encoded for a granulin protein of 250 amino acids with a molecular mass of 29.5 ± 0.7 kDa. This amino acid sequence exhibited significant homology with Spodoptera litura granulovirus (SpliGV) and other GVs infecting insects in the same Noctuidae family of Lepidoptera. Peptide analysis of granulin protein indicated close homology with that of SpliGV. Virtual RFLP patterns from in silico digestions of granulin gene of 18 granuloviruses mapped by 12 restriction enzymes were used for simulated digestions. Implications of the phylogenetic relationships of granulin nucleotide and deduced amino acid sequence are discussed. We have established the sequence identity of granulin gene of AcjaGV and characterized its protein product and the phylogenetic relationship with other known GVs. Our results indicate the presence of unique restriction sites for three restriction enzymes, and this can be used as a tool for identification of AcjaGV from various sources. This is the first report from the Indian subcontinent to describe the complete granulin gene of a GV isolated from A. janata.

Characterization of a granulovirus isolated from Epinotia aporema Wals. (Lepidoptera: Tortricidae) larvae

A granulovirus (GV) isolated from Epinotia aporema (Lepidoptera: Tortricidae)-a major soybean pest-was studied in terms of its main morphological, biochemical, and biological properties. The ovoidal occlusion bodies were 466 by 296 nm in size, and their most prominent protein had an apparent molecular mass of 29 kDa. Its amino-terminal sequence was remarkably homologous to that of the granulins of other GVs. The DNA genome size was estimated to be 120 kbp. The high specificity and pathogenicity of this newly described granulovirus (EpapGV) indicate that it is indeed a good candidate for the biological control of this pest.

Characterization of a granulovirus from the cassava hornworm (Erinnyis ello: Sphingidae)

A Colombian isolate of Erinnyis ello granulovirus (EeGV) was characterized by electron microscopy, restriction endonuclease digestion, and SDS-PAGE. Electron microscopy showed the occlusion bodies to have a morphology typical of granuloviruses. The restriction patterns of DNA from EeGV and the granuloviruses of Trichoplusia ni (TnGV) and Pieris rapae (PrGV) show little or no similarity, indicating little relatedness among these viruses. EeGV was estimated to possess a relatively small genome of 90.5 +/- 0.5 kbp. SDS-PAGE analysis compared the occulsion body and enveloped nucleocapsid proteins of EeGV and TnGV, and the polypeptide patterns also showed little similarity between these viruses. These analyses, as well as comparison of our results to those reported for other granuloviruses, indicate that EeGV represents a new granulovirus isolate.