Grudgingly sharing their secrets:new insight into the evolution ofplant pathogenic bacteria

摘要

The conventional wisdom regarding bacterial plant pathogens isthat strains found causing disease on plants are specialized anddistinct from saprophytic strains found in the environment (soil,water, decaying plant material) that have no apparent role indisease. In this issue of New Phytologist, Monteil et al. (pp. 800–811) show that environmental populations are likely to have had arole in the emergence of Pseudomonas syringae pv. tomato (Pto),directly as reservoirs of pathogenic or potentially pathogenic strainsand indirectly as sources of novel genetic variation that isintroduced to pathogenic strains via recombination. They foundstrong signatures of recombination in P. syringae when diseaseassociatedstrains of Pto were analyzed together with environmentalstrains collected from alpine snow and creeks.