Bacterial microbiota protect an invasive bark beetle from a pine defensive compound

Area of Science:

• Ecology
• Microbiology
• Entomology

Background:

• Biotic invasions can be facilitated by microbial symbionts.
• The red turpentine beetle (RTB) invasive complex with fungus Leptographium procerum in China attacks healthy pines.
• RTB symbionts degrade pine defenses (naringenin), but microbes in galleries detoxify it.

Purpose of the Study:

• Elucidate functional roles of microbial players in RTB gallery symbiosis.
• Investigate microbial degradation of naringenin and its impact on RTB fitness.
• Understand the mechanism of symbiotic invasion in forest ecosystems.

Main Methods:

• Analyzing gallery microbiota composition and naringenin degradation activity.
• Identifying bacterial phylotypes correlated with degradation.
• Assessing RTB survivorship and fitness with isolated bacteria.

Main Results:

• Symbiotic microbiota increase RTB survivorship against host defenses.
• Bacterial community structure correlates with naringenin degradation.
• Novosphingobium bacteria possess degradation genes and enhance RTB fitness.

Conclusions:

• RTB gallery bacteria degrade naringenin, enhancing beetle fitness and invasion success.
• This microbial symbiosis overcomes tree defenses, facilitating the invasive beetle-fungi complex.
• The study reveals a mechanism in invasion ecology for mitigating biotic resistance.