Comparative Gene Expression Patterns of Two EcobNPV Strains in Ectropis grisescens Revealed by Transcriptome Analysis

Area of Science:

• * Virology
• * Molecular Biology
• * Entomology

Background:

• * Ectropis obliqua nucleopolyhedrovirus (EcobNPV) is a key biological control agent for Lepidopteran pests.
• * A specific strain, EcobNPV-QF4, demonstrates superior virulence compared to the original EcobNPV-QV strain.
• * The molecular mechanisms driving this virulence difference are not well understood.

Purpose of the Study:

• * To investigate the transcriptional differences between virulent EcobNPV-QF4 and less virulent EcobNPV-QV strains.
• * To elucidate the molecular basis for the enhanced virulence of EcobNPV-QF4 in E. grisescens.

Main Methods:

• * Comparative time-course transcriptomic analysis (RNA-seq) of E. grisescens infected with EcobNPV-QF4 and EcobNPV-QV.
• * Bioassays (leaf-dipping) to confirm virulence differences.
• * Quantitative reverse transcription PCR (qRT-PCR) for RNA-seq data validation.

Main Results:

• * EcobNPV-QF4 induced significantly higher larval and pupal mortality than EcobNPV-QV.
• * Transcriptomic analysis revealed that EcobNPV-QF4 initiated gene expression approximately 6 hours earlier than EcobNPV-QV.
• * Genes related to midgut escape, virion assembly, and viral DNA replication were coordinately upregulated earlier in EcobNPV-QF4 infections.

Conclusions:

• * The enhanced virulence of EcobNPV-QF4 is attributed to a synergistic, accelerated transcriptional progression.
• * This accelerated process likely compresses the viral infection cycle and improves dissemination.
• * Findings offer insights into baculovirus virulence mechanisms and inform future research.