Microbiota and horizontal microbial transmission dynamics associated with bramble (Rubus spp.) flowers

Area of Science:

• Plant-microbe interactions
• Ecology
• Microbiology

Background:

• Microbes are vital in plant-insect ecological interactions.
• Horizontal microbial transmission via flowers is poorly understood, especially in diverse insect-visited hub plants.

Purpose of the Study:

• To investigate bacterial and fungal communities on bramble flowers.
• To determine the impact of insect visitation and environmental deposition on floral microbiota.

Main Methods:

• 16S rRNA gene and ITS2 metabarcoding were used.
• Bacterial and fungal communities were analyzed in open flowers, insect-excluded bagged flowers, and flower buds.

Main Results:

• Insect visitation and environmental deposition altered floral microbial diversity and load, particularly for bacteria.
• Insect visitation enriched fermentative and potentially pathogenic bacteria, including Spiroplasma.
• Floral microbial networks differed, with bagged flowers showing more internal connectivity and open flowers more centralization.

Conclusions:

• Insect visitation is a dominant factor shaping floral microbiota.
• Hub plants play a significant role in horizontal microbial transmission within plant-pollinator networks.