Artificial Selection on Microbiomes To Breed Microbiomes That Confer Salt Tolerance to Plants

Area of Science:

• Microbiology
• Plant Science
• Agricultural Science

Background:

• Salt stress significantly limits crop growth and seed production, impacting global food security.
• Developing strategies to enhance plant resilience to salinity is crucial for sustainable agriculture.

Purpose of the Study:

• To develop and validate an improved artificial selection protocol for engineering rhizosphere microbiomes that confer salt tolerance to plants.
• To assess the efficacy of the developed protocol in enhancing the fitness and seed production of *Brachypodium distachyon* under salt stress.

Main Methods:

• Improved artificial selection protocol involving controlled microbiome assembly, fractionation of bacterial and viral components, gradual salt stress application, and nonselection controls.
• Differential propagation of rhizosphere microbiomes between plants of a non-evolving *Brachypodium distachyon* population over multiple selection cycles.
• Quantitative assessment of plant seed production and stress tolerance in response to microbiomes selected under sodium and aluminum salt stress conditions.

Main Results:

• The developed protocol generated salt-tolerant microbiomes after only 1-3 rounds of selection, significantly enhancing plant fitness.
• Microbiomes selected for aluminum salt tolerance showed nonspecific effects, ameliorating both sodium and aluminum stress.
• Plants inoculated with selected microbiomes exhibited 55-205% greater seed production under extreme salt stress compared to controls.

Conclusions:

• The improved artificial selection method is highly effective in rapidly breeding plant microbiomes for enhanced salt tolerance.
• Artificially selected microbiomes hold significant potential for improving agricultural productivity in saline environments.
• The study provides a robust framework for future research into microbiome engineering for plant stress resilience.