Comparative Analysis of HaSNPV-AC53 and Derived Strains

Area of Science:

• Virology
• Genomics
• Insect Pathology

Background:

• Helicoverpa armigera single nucleopolyhedrovirus (HaSNPV) is a significant insect pathogen.
• Understanding baculovirus genetic diversity is crucial for biological control applications.

Purpose of the Study:

• To analyze the complete genome sequences of Australian HaSNPV isolates and their tissue culture-derived strains.
• To investigate genetic polymorphisms and evolutionary patterns in HaSNPV.

Main Methods:

• Whole genome sequencing of Australian HaSNPV isolates and nine derived strains.
• Identification and comparison of nucleotide and amino acid sequence polymorphisms in open reading frames (ORFs).
• Phylogenetic analysis using maximum likelihood estimation (MLE) to compare with global HaSNPV isolates.

Main Results:

• Tissue culture passage induced multiple polymorphisms in HaSNPV strains compared to the parent isolate.
• Six ORFs showed identical amino acid changes across all nine derived strains.
• Australian HaSNPV isolates exhibited genetic similarities to both New World (H. zea) and Old World (H. armigera) SNPVs.
• Three distinct geographic clusters of HaSNPV genomes were identified: Australia/Americas, Europe/Africa/India, and China.

Conclusions:

• In vitro passage and geographic origin significantly influence HaSNPV strain selection and evolution.
• Geographic movement plays a key role in shaping baculovirus genetic diversity.
• The findings provide insights into the evolutionary dynamics of HaSNPV populations worldwide.