Two sebacinoid ectomycorrhizae on Chinese pine

Abstract

Sebacinoid fungi show a broad mycorrhizal capacity; therefore, they play a very important role in natural systems. Worldwide, fungi of Sebacinales are present under different environmental conditions and associate with diverse plant hosts, however, are hitherto poorly studied in China. Two sebacinoid ectomycorrhizae (ECM), Pinirhiza multifurcata and Pinirhiza nondextrinoidea, are described in detail morphologically and anatomically in the present study. They share a plectenchymatous outer mantle with multiply ramified hyphae in a gelatinous matrix, clampless, thin, thick-walled emanating hyphae with mostly Y-shaped ramifications and triangular inflations at the point of ramification. P. multifurcata and P. nondextrinoidea can be distinguished by thick cells in mantle layers, the ramification of emanating hyphae, the presence or absence of rhizomorphs, as well as the differing color reaction in Melzer's reagent. The putative molecular phylogenetic relationships of P. multifurcata and P. nondextrinoidea were inferred by analyses of the partial large subunit nuclear rDNA (nLSU); however, an affiliation to fungal species was not possible. This is the first report of sebacinoid ECM on Chinese pine.

Enigmatic Sebacinales

“…In an old-growth Mediterranean forest dominated by Q. ilex, Sebacinales ECMs play an essential role (Richard et al 2005;. Quercirhiza dendrohyphidiomorpha on Q. suber in Portugal (Azul et al 2006) is considered a sebacinoid ECM (Wei and Agerer 2011). Sebacina sp.…”

Experimental evidence of ericoid mycorrhizal potential within Serendipitaceae (Sebacinales)

“…These include arbutoid (Richard et al 2005;Kühdorf et al 2014), cavendishioid (Setaro et al 2006), ericoid (see below), jungermannoid (Kottke et al 2003;Newsham and Bridge 2010), orchid (e.g., Warcup and Talbot 1967;Dearnaley et al 2009;Wright et al 2010), and pyroloid (e.g., Tedersoo et al 2007;Vincenot et al 2008;Hashimoto et al 2012) mycorrhizae, as well as ectomycorrhizae (e.g., Selosse et al 2002;Urban et al 2003;Wei and Agerer 2011). Sebacinales are phylogenetically divided into two families, namely, Sebacinaceae (formerly Group or Clade A) and Serendipitaceae (Group/Clade B), which also differ in ecology (including mycorrhizal potential) and cultivability (Weiss et al 2004;Oberwinkler et al 2013;Oberwinkler et al 2014;Weiss et al 2016).…”

New Neotropical Sebacinales Species from a Pakaraimaea dipterocarpacea Forest in the Guayana Region, Southern Venezuela: Structural Diversity and Phylogeography

“…The transition between a dense plectenchyma of thick-walled ramified hyphae and a pseudoparenchyma in Sebacinoid ECM M2 [56] and Sebacinoid ECM Y62M1 [8], [70] was also observed in the outer mantle of S. guayanensis . A superficial hyphal net with variably shaped hyphae as in S. tomentosa and in S. guayanensis has also been reported from Sebacina incrustans + Picea abies and Sebacinoid ECM Y62M1 [70], Quercirhiza dendrohyphidiomorpha [71] and Pinirhiza multifurcata [72]. Thick-walled hyphae in the outer mantle layers and/or emanating elements, smooth cell walls and hyphal inflations as observed in the three species associated with P. dipterocarpacea are a general feature of Sebacinales ECM (Fig.…”

“…An occasional presence of up to five emanating hyphae glued together for short distances of about 100 µm has been reported for Sebacina incrustans + Picea abies [70]. Infrequent type A/B rhizomorphs were recorded for Pinirhiza nondextrinoidea [72]. Type B rhizomorphs in S. guayanensis and Sebacinales specimen 6MM2 were more differentiated than those in previously described Sebacinales anatomotypes.…”

“…9). Polytomies observed either in the superficial hyphal net ( S. guayanensis and S. tomentosa ) or in the emanating hyphae (specimen 6MM2) were reported in several Sebacinales anatomotypes including Sebacinoid ECM M2 [56], Sebacinoid ECM Y62M1 and Sebacina incrustans + Picea abies [70], and Pinirhiza multifurcata + Pinus tabulaeformis [72]. The hydrophilic character of both S. guayanensis and S. tomentosa , and the dextrinoid reaction recorded in S. guayanensis is a common feature of Sebacinales ECM [50].…”