1. Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
2. Friedrich Miescher-Institut for Biomedical Research, PO Box 2543, CH-4002 Basel, Switzerland

Correspondence to: Igor Kovalchuk¹ Correspondence and requests for materials should be addressed to I.K. (Email: igor.kovalchuk@uleth.ca).

Abstract

Plant genome stability is known to be affected by various abiotic environmental conditions^{1, 2, 3, 4, 5, 6, 7}, but little is known about the effect of pathogens. For example, exposure of maize plants to barley stripe mosaic virus seems to activate transposable elements^{8, 9} and to cause mutations in the non-infected progeny of infected plants¹⁰. The induction by barley stripe mosaic virus of an inherited effect may mean that the virus has a non-cell-autonomous influence on genome stability. Infection with Peronospora parasitica results in an increase in the frequency of somatic recombination in Arabidopsis thaliana¹¹; however, it is unclear whether effects on recombination require the presence of the pathogen or represent a systemic plant response. It is also not clear whether the changes in the frequency of somatic recombination can be inherited. Here we report a threefold increase in homologous recombination frequency in both infected and non-infected tissue of tobacco plants infected with either tobacco mosaic virus¹² or oilseed rape mosaic virus¹³. These results indicate the existence of a systemic recombination signal that also results in an increased frequency of meiotic and/or inherited late somatic recombination.