Nutrient- and Dose-Dependent Microbiome-Mediated Protection against a Plant Pathogen

Area of Science:

• Plant pathology
• Microbiome research
• Agricultural science

Background:

• Plant-associated microbes influence plant health, nutrient uptake, and pathogen resistance.
• Mechanisms of microbiome-mediated plant defense are well-studied in root-associated bacteria but less understood in above-ground (phyllosphere) communities.
• The role of whole phyllosphere microbial communities in conferring host resistance against pathogens remains largely unexplored.

Purpose of the Study:

• To investigate whether augmented tomato phyllosphere microbiomes can confer resistance against the bacterial speck pathogen, Pseudomonas syringae pathovar tomato (Pst).
• To determine the influence of commensal bacteria dose and microbial composition on protection.
• To explore the role of available resources, such as fertilizer, in microbiome-mediated protection.

Main Methods:

• Augmentation of tomato phyllosphere microbiomes.
• Inoculation with Pseudomonas syringae pathovar tomato (Pst) to assess pathogen colonization.
• Varying doses of commensal bacteria and fertilizer application to evaluate their impact on protection.

Main Results:

• Augmented phyllosphere microbiomes consistently reduced Pst colonization across five experiments.
• The degree of protection was influenced by the dose of applied commensal bacteria.
• Microbiome-mediated protection was abolished by the addition of fertilizer, indicating the importance of resource availability.

Conclusions:

• Augmented phyllosphere microbial communities can enhance plant resistance to foliar pathogens like Pst.
• Resource availability, influenced by factors like fertilizer, plays a critical role in the efficacy of microbiome-mediated protection.
• These findings have implications for developing plant probiotics in agricultural settings to improve disease resistance.