Present address: Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
Evidence for interspecies transmission of viruses in natural populations of filamentous fungi in the genus Cryphonectria
Article first published online: 1 MAY 2003
Volume 12, Issue 6, pages 1619–1628, June 2003
How to Cite
Liu, Y.-C., Linder-Basso, D., Hillman, B. I., Kaneko, S. and Milgroom, M. G. (2003), Evidence for interspecies transmission of viruses in natural populations of filamentous fungi in the genus Cryphonectria. Molecular Ecology, 12: 1619–1628. doi: 10.1046/j.1365-294X.2003.01847.x
- Issue published online: 1 MAY 2003
- Article first published online: 1 MAY 2003
- Received 28 August 2002; revision received 24 January 2003; accepted 18 February 2003
- chestnut blight;
- fungal virus;
- interspecies transmission;
Interspecies transmission is a significant evolutionary event that has allowed a variety of pathogens to invade new host species. We investigated interspecies transmission of viruses between the chestnut blight fungus, Cryphonectria parasitica, and a sympatric unidentified Cryphonectria species in Japan. Two isolates of Cryphonectria sp. were found to contain Cryphonectria hypovirus 1 (CHV-1), which has been typically found in C. parasitica. Three lines of evidence support the hypothesis of interspecies transmission of CHV-1. First, host species occur sympatrically and therefore have the opportunity to come into physical contact. Second, we transmitted CHV-1 between species experimentally in the laboratory. Third, phylogenetic analysis of 476 bp of the ORF B region of CHV-1 showed that sequences from Cryphonectria sp. were more closely related to those from C. parasitica than to each other. Local geographical subdivision of virus sequences from both host species argues against the alternative hypothesis of independent evolution of CHV-1 since speciation of their hosts. Based on these findings, we rule out the hypotheses that CHV-1 diverged from viruses in a common ancestor of the hosts, or that ancestral polymorphisms in CHV-1 persisted in the two host taxa. Estimating the direction and frequency of interspecies transmission in nature will require more extensive samples of CHV-1 from both host species.