Phialocephala sphaeroides sp. nov., a new species among the dark septate endophytes from a boreal wetland in Canada

Abstract

Dark septate root endophytic fungi from plants growing on either side of an abrupt wetland–upland ecotone included isolates of Phialocephala fortinii Wang & Wilcox, Leptodontidium orchidicola Sigler & Currah, Hetero conium chaetospira (Grove) Ellis, and a hitherto undescribed fungus resembling P. fortinii. Six isolates of this species were recovered and were distinctive in (i) producing an orange–tan diffusible pigment in culture, (ii) causing a yellow colour shift on casamino acids medium containing bromocresol purple, (iii) having the ability to liquefy gelatin, and microscopically, (iv) forming hyaline conidia from phialides arranged in large spherical heads after prolonged incubation at 5 °C. First-formed or primary conidia are bullet shaped, 1–1.5 µm × 2–3 µm; subsequent conidia are spherical and 1–1.5 µm in diameter. Small subunit and internal transcribed spacer region sequence comparisons with P. fortinii and other Phialocephala species supported placing these six unique strains in a new species, Phialocephala sphaeroides B.J. Wilson sp. nov. Phylogenetic analyses also suggest that P. sphaeroides is affiliated with mollisioid taxa in the Dermateaceae. In contrast with P. fortinii, which was isolated on both sides of the ecotone, P. sphaeroides was obtained only from plants in the highly acidic, Sphagnum-dominated wetland habitat and not from the same species in the less acidic, aspen-dominated upland site.Key words: inoperculate discomycetes, phialidic anamorph, Helotiales, root endophytes, Loramycetaceae, Dermateaceae, Mollisia.

Paleomycology of the Princeton Chert II. Dark-septate fungi in the aquatic angiospermEorhiza arnoldiiindicate a diverse assemblage of root-colonizing fungi during the Eocene

“…Because the host-fungus interface of DSE involves a network of non-chitinous mucilaginous hyphae (Barrow 2003), direct evidence by which to discriminate an asymptomatic endophyte from a saprotrophic root colonizer is unlikely to be observed in the fossil record, although additional investigations may yield associated conidia. Conidiogenesis can be diagnostic for a number of root endophytes (Fernando andCurrah 1995, Addy et al 2005) but is often rare, frequently occurring only after a period of vernalization (Wilson et al 2004, Addy et al 2005. Because the sterile mycelia of most DSE are morphologically similar, we currently are unable to more precisely delimit the systematic affinities of these fossils, although the occurrence of two types of survival anamorphs indicates that more than one species of root colonizing fungi might have been present.…”

Sexual and asexual states of some endophyticPhialocephalaspecies ofPicea

“…Molecular evidence has indicated repeatedly a close relationship among named Phialocephala species and some species of Mollisia, a teleomorph genus associated with phialocephala-like asexual states (Vrålstad et al 2002, Wilson et al 2004, Menkis et al 2005, Zijlstra et al 2005, Wu and Guo 2008, Grünig et al 2009, Day et al 2012). In its current taxonomic state Mollisia is an unwieldy para-and polyphyletic genus requiring significant taxonomic revision, with at least 230 described species that are difficult or impossible to differentiate morphologically (Greenleaf and Korf 1980).…”

Potential of the Endophytic Fungus Phialocephala fortinii Rac56 Found in Rhodiola Plants to Produce Salidroside and p-Tyrosol

“…The rDNA sequence of Rac56 (KJ542292, 519 bp) and its closest related species available at GenBank were selected for construction of NJ phylogenetic tree using MEGA 4.0 program after sequence alignment with Clustal W. The endophytic fungus Rac56 was found to be closely related to Phialocephala fortinii (AY394915 and AY394921) (Figure 2c) with 99% homology. The morphological characteristic described above corresponded to anamorphic P. fortinii [16][17][18][19][20], which led to its designation as P. fortinii.…”

“…The morphological characteristic described above corresponded to anamorphic P. fortinii [16][17][18][19][20], which led to its designation as P. fortinii. …”