Diverse rhizospheric Bacillus are required for protection against a leaf pathogen

Area of Science:

• Microbiology
• Plant Pathology
• Ecology

Background:

• Plant health relies on a protective microbiota, and disruptions lead to increased susceptibility to pathogens.
• Understanding the mechanisms of microbial plant defense is crucial for developing sustainable agricultural practices.

Purpose of the Study:

• To identify critical microbial components involved in plant defense within a complex synthetic community.
• To investigate the mechanisms and diversity-dependent effects of microbial protection against plant pathogens.

Main Methods:

• A 150-member bacterial synthetic community was established with Arabidopsis plants in a plant-soil-microbiome microcosm.
• The microcosm was deconstructed by removing microbial groups to assess their impact on plant defense against Pseudomonas syringae pv. tomato DC3000.
• Plant RNA sequencing and bacterial co-culturing were used to analyze defense mechanisms.

Main Results:

• The genus Bacillus was identified as critical for protecting plants against infection.
• Bacillus-mediated protection was found to be independent of plant immune system activation.
• Plant protection levels were significantly influenced by the diversity of the protective bacterial inoculum.

Conclusions:

• The genus Bacillus plays a vital role in plant defense against pathogens.
• High within-genus diversity of bacterial inocula can significantly improve biocontrol strategies.
• Microbial plant-soil-microbiome interactions offer promising avenues for enhancing plant resilience and disease resistance.