Host Associations Between Fungal Root Endophytes and Boreal Trees

Abstract

Fungal root endophytes colonize root tissue concomitantly with mycorrhizal fungi, but their identities and host preferences are largely unknown. We cultured fungal endophytes from surface-sterilized Cenococcum geophilum ectomycorrhizae of Betula papyrifera, Abies balsamea, and Picea glauca from two boreal sites in eastern Canada. Isolates were initially grouped on the basis of cultural morphology and then identified by internal transcribed spacer ribosomal DNA sequencing or by PCR restriction fragment length polymorphism. Phylogenetic analysis of the sequence data revealed 31 distinct phylotypes among the isolates, comprising mainly members of the ascomycete families Helotiaceae, Dermateaceae, Myxotrichaceae, and Hyaloscyphaceae, although other fungi were also isolated. Multivariate analyses indicate a clear separation among the endophyte communities colonizing each host tree species. Some phylotypes were evenly distributed across the roots of all three host species, some were found preferentially on particular hosts, and others were isolated from single hosts only. The results indicate that fungal root endophytes of boreal trees are not randomly distributed, but instead form relatively distinct assemblages on different host tree species.

Diversity and host preference of fungi co-inhabiting Cenococcum mycorrhizae

“…Recent evidence also indicates that some fungal root endophytes exhibit preference for particular host plants (Gr€ unig et al, 2008;Tedersoo et al, 2009;Kernaghan and Patriquin, 2011;Quilliam and Jones, 2012;Tejesvi et al, 2013), although examples of specificity at levels seen in some ECM fungi are lacking (Molina et al, 1992;Toju et al, 2013a). There is also increasing evidence that some fungal root endophytes prefer ECM formed by particular species of ectomycorrhizal fungi (Urban et al, 2008;Tedersoo et al, 2009;Izumi and Finlay, 2011;Yamamoto et al, 2014), potentially representing a second level of root endophyte selection.…”

“…Although DSE are common, woody roots and ECM are colonized by a much more diverse array of fungi, including many non-melanized species, as demonstrated by several culture dependent (Schild et al, 1988;Fisher et al, 1991;Girlanda and Luppi-Mosca, 1995;Girlanda et al, 2002;Hoff et al, 2004;Summerbell, 2005;Kernaghan and Patriquin, 2011), and culture independent studies (Kernaghan et al, 2003;Kwa sna et al, 2008;Urban et al, 2008;Tedersoo et al, 2009;Izumi and Finlay, 2011;Toju et al, 2013a).…”

“…In a previous study (Kernaghan and Patriquin, 2011), we investigated species composition, diversity and host preference in fungal root endophyte communities of ECM of boreal trees using culture-based techniques. To focus on differences among host plant species, and to avoid the potential influence of preference for ectomycorrhizal symbionts, ECM formed by Cenococcum geophilum (Cg) were focused on.…”

Diversidad, ecología e importancia potencial de los hongos endófitos septados obscuros en México

“…Los medios de cultivo utilizados para el aislamiento son variados; por ejemplo, se ha utilizado el medio Czapek enriquecido con sacarosa, agar extracto de malta (AEM), medio de malta-levadura (MML), medio Melin-Norkrans (MMN), agar papa-dextrosa (APD), agar soya-tríptica (AST; Kernaghan et al, 2003;Kernaghan y Patriquin, 2011). En estos medios de cultivo se recomienda aplicar antibióticos (estreptomicina, ampicilina, tetraciclina, oxitetraciclina, penicilina y cloranfenicol) que eviten el crecimiento de bacterias (Yuan et al, 2010b), o bien, usar fungicidas como el benomil (Kernaghan et al, 2003;Kernaghan y Patriquin, 2011). Las muestras se incuban en oscuridad bajo un intervalo de temperatura de 20-25 °C.…”

Microbial Diversity: The Gap between the Estimated and the Known

“…Accordingly, numerous studies have shown that host preference or recurrence is important for the formation of biotrophic [165][166][167][168], lignolytic [50], and pathogenic [169] fungal communities. Thus, the description of all microbial diversity apparently requires an assessment of all hosts and habitats.…”