AMANITA - What makes Amanita phalloides a successful invader? Insights from studies in its native range
Coordinator - Susana C. Gonçalves
Programme - COMPETE
Execution dates - 2012-05-04 - 2015-05-03 (36 Months)
Funding Entity - FCT (PTDC/BIA-BIC/122142/2010)
Funding for Grupo - 179 508.00 €
Total Funding - 179 508 €
Proponent Institution - University of Coimbra, Portugal
Participating Institutions
Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Portugal

Department of Organismic and Evolutionary Biology, Harvard University, USA (Anne Pringle)


Despite the ecological significance of ectomycorrhizal (ECM) fungi and potential effects of introduced ECM fungi on ecosystem functioning, only in recent times have there been studies focusing on this group of fungi in the context of invasion biology (e.g. Murat et al. 2008). Vellinga et al. (2009) have estimated that at least 200 species of ECM fungi were moved from native ranges to novel ranges, either in soil or in the roots of their hosts. Although most introduced ECM species apparently only associate with their exotic hosts and do not spread to native hosts, some introduced ECM fungi have shifted host to associate with native ECM tree species and become invasive (Johnston et al. 1998, Díez 2005, Pringle et al. 2009). Promiscuous ECM fungi that associate with a wide range of hosts in their native habitat are thought to easily associate with native hosts in novel habitats and for this reason successfully spread (Vellinga et al. 2009).


Recent data provided evidence for an European origin of North American populations of the ECM fungus Amanita phalloides (Pringle et al. 2009, Wolfe et al. 2010). In California, A. phalloides is spreading and has been shown to predominantly associate with native Quercus agrifolia (Wolfe et al. 2010). In contrast, in the east coast it is considered relatively rare and appears most often associated with Pinus spp. in planted forests (Wolfe et al. 2010). In Europe (the native range of A. phalloides), systematic surveys on host associations of A. phalloides have never been made. Even though A. phalloides appears to be a generalist species, the hypothesis of mutualists’ flexibility in native and introduced ranges (Richardson et al. 2000) is at odds with available data on host associations of A. phalloides in North America. The research described in this proposal aims at dissecting possible genetic and ecological controls on host associations of A. phalloides in its native range. We hypothesize that: 1) A. phalloides associates with a wide phylogenetic range of hosts in Europe, 2) Different lineages of A. phalloides associate with different hosts in the native range, and that 3) Diversity of ECM fungi communities determines the abundance of A. phalloides in those communities.


When fruiting, ECM fungi are charismatic features of forests. However, fungal individuals are typically hidden within soil. Thus, ecologists must take advantage of the current array of tools that allow peeking into the soil “black box”. We will use a variety of molecular tools that have been developed for A. phalloides, including inexpensive and high-throughput diagnostic polymerase chain reaction (PCR) for identifying the species from root tips, and protocols for genetic fingerprinting of sporocarps using amplified fragment length polymorphisms (AFLPs). To estimate the abundance of extramatrical mycelia of A. phalloides relative to other fungi in the ECM fungal community, we will follow a mesh bag approach (Wallander et al. 2001) and use real-time quantitative PCR (qPCR). Profiling of ECM fungal communities will be performed using the recently developed 454 pyrosequencing technology.


Expected results from this research project will provide insight into the behavior of the ECM A. phalloides in North America, where it was introduced (Pringle et al. 2009). More specifically, the results will provide information about the genetic and ecological mechanisms controlling host associations of A. phalloides, and will elucidate how changes in belowground symbiosis between ECM fungi and their hosts may facilitate or constrain the invasion process, providing the basis for the development of A. phalloides as a model in the field of invasion biology of ECM fungi.



 



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