Intestinal microbiome interactions influence Metarhizium-based biocontrol efficacy against the sugar beet weevil

Area of Science:

• Agricultural Entomology
• Microbial Ecology
• Biological Pest Control

Background:

• The sugar beet weevil is a significant pest in sugar beet farming.
• Entomopathogenic fungi, like Metarhizium brunneum, show promise for biological control.
• Insect gut microbiomes can influence susceptibility to pathogens, impacting biocontrol efficacy.

Purpose of the Study:

• To investigate how intestinal microbial interactions affect mycosis caused by Metarhizium fungi in sugar beet weevils.
• To identify specific gut microbes that modulate the weevil's susceptibility to entomopathogenic fungi.
• To explore potential synergistic or antagonistic interactions for improved biological control strategies.

Main Methods:

• Analysis of the intestinal microbiome in both treated (with Metarhizium) and untreated sugar beet weevils.
• Comparison of microbial communities in mycotic (fungal infection) versus non-mycotic individuals at death.
• Identification of bacterial genera associated with different infection outcomes.

Main Results:

• Pantoea and Enterobacter were significantly associated with mycotic individuals, suggesting they may antagonize Metarhizium.
• Healthy, non-mycotic weevils possessed diverse gut microbial communities, potentially offering a protective barrier.
• Serratia, Penicillium, and Cladosporium were found in non-mycotic individuals and may have insecticidal properties, particularly in males.

Conclusions:

• Gut microbiome composition influences sugar beet weevil susceptibility to Metarhizium infections.
• Specific bacteria like Pantoea and Enterobacter could be antagonists, while others like Serratia may enhance biocontrol.
• Further research into these microbial interactions could lead to more effective and sustainable Metarhizium-based pest management strategies.