|Van der putten, Wim|
Submitted to: New Phytologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/2/2009
Publication Date: 1/19/2010
Citation: Reinhart, K.O., Tytgat, T.O., Van Der Putten, W.H., Clay, K. 2010. Virulence of soil-borne pathogens and invasion by Prunus serotina. New Phytologist. 186:484-495. Interpretive Summary: Invasive non-native species threaten natural resources • Soil-borne pathogens from the native range of black cherry were more destructive than those from its non-native range. • Variation in pathogenic activity corresponded with shifts in pathogen species composition more than variation in pathogenic activity of a common species. • Interactions occurring in the soil are often treated as a “black box.” This research is unique because it shows how plant-pathogen interactions occurring in the soil may affect plant invasions. • Theoretical implications- Although invaders likely encounter natural enemies in new places, these new enemies are likely less aggressive than those encountered in its native range. • Management implications- Resident plant pathogens may be aggressive enough to be incorporated into management plans to control invasive non-native species without the risks associated with introducing conventional biological control agents.
Technical Abstract: Exotic invaders are a global threat to biodiversity and ecosystem function. Experimental studies find invading species less affected by enemies in their invaded vs. home ranges, but little is known about the underlying mechanisms. Here, we show that soil-borne Pythium pathogens are commonly associated with soil surrounding the invasive tree Prunus serotina in both its native USA and non-native invaded European ranges. However, isolates from its native range caused more mortality ((>or=)80%) and root rot ((>or=)38%) and less biomass production ((<or=)19%) of seedlings than Pythium from the non-native range in controlled pathogenicity experiments. Molecular phylogenetic analysis indicated that the most aggressive Pythium types were confined to the native range, whereas mildly pathogenic types occurred in both the native and non-native ranges. There were some pathogenic Pythium isolates from the non-native range, indicating the potential for pathogens to eventually control the density of P. serotina in invaded forests. Understanding why invading species are less affected by resident enemies is critically important for predicting and controlling exotic plants in their new ranges.