Pathogen-induced systemic DNA rearrangement in plants.

Infection of tobacco plants with tobacco mosaic virus and oilseed rape mosaic virus was shown to induce a threefold increase in homologous DNA recombination in non-infected tissues. Grafting experiments by Igor Kovalchuk et al. demonstrated that this increase was mediated by a systemic recombination signal that traveled ahead of the virus. A similar increase in DNA recombination was also observed in the progeny of the infected plants, indicating that pathogen-induced recombination can lead to heritable adaptations to environmental stresses.