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A mycovirus enhances fitness of an insect pathogenic fungus and potentially modulates virulence through interactions between viral and host proteins

Summary

Scientists discovered a virus that infects Beauveria bassiana, a fungus used to control pests naturally. This virus actually helps the fungus by making it produce more spores, survive harsh conditions like sunlight and heat, and kill target insects faster. The virus does this by interacting with specific fungal proteins that control reproduction, stress response, and virulence. This discovery could lead to better biological pest control products that are more effective and reliable than current options.

Background

Beauveria bassiana is an entomopathogenic fungus used in biological pest control, but its effectiveness is limited by low conidiation rates, environmental stress sensitivity, and delayed insecticidal activity. Mycoviruses can have variable effects on fungal hosts, ranging from detrimental to mutualistic interactions. This study identifies a mycovirus (BbPmV4-2) with potential to enhance fungal biocontrol properties.

Objective

To identify, characterize, and determine the mechanisms by which Beauveria bassiana polymycovirus 4-2 (BbPmV4-2) enhances the fitness and modulates virulence of its entomopathogenic fungal host. The study aims to elucidate molecular interactions between viral and host proteins that confer stress tolerance and hypervirulence.

Results

BbPmV4-2 comprises eight dsRNA segments with three unique segments not previously identified in related mycoviruses. Virus-infected strains exhibited nearly doubled conidial yields, increased tolerance to UV irradiation and heat shock, and reduced median lethal time against G. mellonella larvae. Viral protein P5 directly interacts with host proteins BbGAP1 (GPI-anchored membrane protein) and BbSDU1 (deubiquitinating enzyme), mediating enhanced stress tolerance and virulence through upregulation of stress response and virulence-associated genes.

Conclusion

BbPmV4-2 represents a beneficial mycovirus that enhances B. bassiana fitness and potential virulence through specific viral-host protein interactions. The elucidated molecular mechanisms provide a foundation for optimizing mycovirus-mediated enhancements in biological pest control. These findings demonstrate the potential of harnessing mutualistic virus-host interactions to develop more effective and resilient fungal biocontrol agents.
  • Published in:PLoS Pathogens,
  • Study Type:Experimental Research,
  • Source: PMID: 41129597, DOI: 10.1371/journal.ppat.1013634
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