Ericaceous dwarf shrubs affect ectomycorrhizal fungal community of the invasive Pinus strobus and native Pinus sylvestris in a pot experiment

Abstract

This study aimed to elucidate the relationship between ericaceous understorey shrubs and the diversity and abundance of ectomycorrhizal fungi (EcMF) associated with the invasive Pinus strobus and native Pinus sylvestris. Seedlings of both pines were grown in mesocosms and subjected to three treatments simulating different forest microhabitats: (a) grown in isolation and grown with (b) Vaccinium myrtillus or (c) Vaccinium vitis-idaea. Ericaceous plants did not act as a species pool of pine mycobionts and inhibited the ability of the potentially shared species Meliniomyces bicolor to form ectomycorrhizae. Similarly, Ericaceae significantly reduced the formation of Thelephora terrestris ectomycorrhizae in P. sylvestris. EcMF species composition in the mesocosms was strongly affected by both the host species and the presence of an ericaceous neighbour. When grown in isolation, P. strobus root tips were predominantly colonised by Wilcoxina mikolae, whereas those of P. sylvestris were more commonly colonised by Suillus and Rhizopogon spp. Interestingly, these differences were less evident (Suillus + Rhizopogon spp.) or absent (W. mikolae) when the pines were grown with Ericaceae. P. strobus exclusively associated with Rhizopogon salebrosus s.l., suggesting the presence of host specificity at the intrageneric level. Ericaceous plants had a positive effect on colonisation of P. strobus root tips by R. salebrosus s.l. This study demonstrates that the interaction of selective factors such as host species and presence of ericaceous plants may affect the realised niche of the ectomycorrhizal fungi.

Designer Niches Promote Seedling Survival in Forest Restoration: A 7-Year Study of Whitebark Pine (Pinus albicaulis) Seedlings in Waterton Lakes National Park

“…Studies have hypothesized that when a Vaccinum understory promotes survival it is because of mycorrhizal facilitation; however, currently there is no evidence to support this hypothesis for whitebark pine. Greenhouse studies with Vaccinium and Pinus strobus L. have shown definitively that Vaccinium is not a source of mycorrhizal fungi for the pine since Vaccinium species associate with ericaceous fungi and pines with ectomycorrhizal fungi [49]. Interestingly, in the Kohout study, adjacent ericaceous plants did promote colonization of P. strobus root tips by the pine-specific ectomycorrhizal fungus Rhizopogon salebrosus A.H.…”

Novel Root-Fungus Symbiosis in Ericaceae: Sheathed Ericoid Mycorrhiza Formed by a Hitherto Undescribed Basidiomycete with Affinities to Trechisporales

“…In many ecosystems, Ericaceae typically form undergrowth of EcM trees and considerable efforts have been invested in determining whether ericoid mycorrhizal and ectomycorrhizal plants share mycorrhizal partners. While a functional mycelial link between ErM and EcM plant has to this point not been demonstrated, rich ecological evidence has accumulated to suggest that such liaisons appear improbable [68], [69], [70]. To conclude, there is currently no evidence to suggest that EcM basidiomycetes detected in Ericaceae roots form functional ericoid mycorrhizae.…”

Ectomycorrhizal fungal communities of native and non-native Pinus and Quercus species in a common garden of 35-year-old trees

“…growing in the Seychelles Islands (Tedersoo et al 2007). Kohout et al (2010) also demonstrated that non-native Pinus strobus effectively adopted EMF assemblages with native fungi in a mesocosm experiment in Czech Republic. Similarly, Parladé et al (1996) demonstrated that 18 EMF species out of 27 collected in northern Spain were able to colonize roots of non-native Pseudotsuga menziesii in a pure culture test.…”