RhizoEvo · Assessing the risks of plant pathogen resistance evolution for the success of microbe-mediated biocontrol

Microbe-mediated plant pathogen biocontrol has been suggested as an environmentally friendly alternative for agrochemicals to increase global food production. While biocontrol bacteria have been shown to suppress the growth of plant pathogenic bacteria via the production of antimicrobials, it remains unclear whether pathogens can escape this by evolving resistance. The main aim of this proposal is to experimentally test whether plant pathogenic Ralstonia solanacearum bacterium can evolve resistant to Pseudomonas protegens biocontrol bacterium in the tomato plant rhizosphere. I will also test if pathogen resistance evolution results in co-evolution and increased antimicrobial activity of the biocontrol bacterium, and if microbial adaptations will affect how both bacteria interact with the tomato plant, potentially shifting plant-microbe interactions along the parasitism-mutualism continuum (virulence vs. plant growth-promotion). To achieve this, I will learn to use a novel experimental-evolution system that allows direct tracking of bacterial adaptation in the rhizosphere of tomatoes over successive plant generations. Training will also be provided to quantify bacterial adaptation using a combination of microbiological assays, genomics, metabolomics and plant assays. The proposed work will help to assess the potential risks of plant pathogen resistance evolution for the long-term efficiency of microbe-mediated biocontrol. It will also improve fundamental understanding of the rapid microbial evolution in an agriculturally relevant model system and help identify potentially novel antimicrobial compounds for future crop protection.