Intraspecific variation in realized dispersal probability and host quality shape nectar microbiomes

Area of Science:

• Microbiology
• Plant Science
• Ecology

Background:

• Epiphytic microbes influence plant phenotype and fitness.
• Microbiome assembly depends on microbe abundance, community composition, host traits, and dispersal.

Purpose of the Study:

• To compare the relative contributions of host-plant filtering and dispersal to nectar microbiome assembly.
• To understand predictable variation in plant microbiome presence, abundance, and composition.

Main Methods:

• Inoculation of synthetic bacterial and yeast communities into four cultivars of Epilobium canum.
• Comparison of inoculated communities with naturally occurring microbes in openly visited flowers.
• Correlation analysis of microbial presence with pollen receipt and floral traits.

Main Results:

• Host-plant filtering significantly influenced microbial presence in synthetic communities.
• Plants with higher inoculated microbial densities did not necessarily have higher densities in open-pollinated flowers.
• Predictable variation in bacterial presence was linked to pollen receipt and floral traits, indicating deterministic dispersal.

Conclusions:

• Host filtering can drive microbiome assembly, particularly in environments with large species pools and high dispersal.
• Deterministic microbial dispersal, influenced by factors like animal vectors or arrival order, can be equally or more critical for microbiome assembly.