What allows bacteria, both pathogens and mutualists alike, to survive in close association with a eukaryotic host? A new study performed a large-scale comparative genomics analysis to identify novel genetic and genomic traits that are enriched in plant-associated bacterial taxa.
Bacteria are found in every conceivable niche on the planet. The ability to associate with either autotrophic (i.e., plant) or heterotrophic (i.e., animal) eukaryotes provides bacteria with access to otherwise unavailable carbon sources1. Bacteria that fill host-associated niches can be mutualistic, pathogenic or neither. Regardless of the effect on the host, for bacteria to live in relatively nutrient-rich host-associated environments, they must have the genetic potential to utilize host nutrients, avoid or suppress host immunity, and compete with the other microbes that are vying for the same niches2. Identifying the genetic arsenal that allows bacteria to compete in host-associated niches including the plant root (‘rhizosphere’) and shoot (‘phyllosphere’) is essential for engineering or manipulating microbial communities for agricultural improvement and for combatting emergent pathogens. In a new study, Asaf Levy, Isai Salas Gonzalez and colleagues3 describe a large-scale comparative genomics approach to identify bacterial genes that are enriched in the genomes of plant-associated bacteria.