Diversity of Root-Associated Fungi of the Terrestrial Orchids Gavilea lutea and Chloraea collicensis in a Temperate Forest Soil of South-Central Chile

The diversity of orchid mycorrhizal fungi (OMF) and other beneficial root-associated fungi in temperate forests has scarcely been examined. This study aimed to analyze the diversity of mycorrhizal and rhizosphere-associated fungal communities in the terrestrial orchids Gavilea lutea and Chloraea collicensis growing in high-orchid-population-density areas in the piedmont of the Andes Cordillera with native forest (Nothofagus-Araucaria) and Coastal Cordillera with an exotic plantation (Pinus-Eucalyptus) in south-central Chile. We focused on rhizosphere-inhabiting and peloton-associated OMF in a native forest (Andes Cordillera) and a mixed forest (Coastal Cordillera). The native terrestrial orchids G. lutea and C. collicensis were localized, mycorrhizal root segments were taken to isolate peloton-associated OMF, and rhizosphere soil was taken to perform the metabarcoding approach. The results revealed that Basidiomycota and Ascomycota were the main rhizosphere-inhabiting fungal phyla, showing significant differences in the composition of fungal communities in both sites. Sebacina was the most-abundant OMF genera in the rhizosphere of G. lutea growing in the native forest soil. In contrast, Thanatephorus was the most abundant mycorrhizal taxa growing in the rhizosphere of orchids from the Coastal Cordillera. Besides, other OMF genera such as Inocybe, Tomentella, and Mycena were detected. The diversity of OMF in pelotons differed, being mainly related to Ceratobasidium sp. and Tulasnella sp. These results provide evidence of differences in OMF from pelotons and the rhizosphere soil in G. lutea growing in the Andes Cordillera and a selection of microbial communities in the rhizosphere of C. collicensis in the Coastal Cordillera. This raises questions about the efficiency of propagation strategies based only on mycorrhizal fungi obtained by culture-dependent methods, especially in orchids that depend on non-culturable taxa for seed germination and plantlet development.

Phylogenetic and Taxonomic Analyses of Three New Wood-Inhabiting Fungi of Xylodon (Basidiomycota) in a Forest Ecological System

Wood-inhabiting fungi are a cosmopolitan group and show a rich diversity, growing in the vegetation of boreal, temperate, subtropical, and tropical regions. Xylodon grandineus, X. punctus, and X. wenshanensis spp. nov. were found in the Yunnan–Guizhou Plateau, China, suggested here to be new fungal species in light of their morphology and phylogeny. Xylodon grandineus is characterized by a grandinioid hymenophore and ellipsoid basidiospores; X. punctus has a membranous hymenophore, a smooth hymenial surface with a speckled distribution, and absent cystidia; X. wenshanensis has a grandinioid hymenophore with a cream to slightly buff hymenial surface and cystidia of two types. Sequences of the ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed using the maximum likelihood, maximum parsimony, and Bayesian inference methods. After a series of phylogenetic studies, the ITS+nLSU analysis of the order Hymenochaetales indicated that, at the generic level, six genera (i.e., Fasciodontia, Hastodontia, Hyphodontia, Lyomyces, Kneiffiella, and Xylodon) should be accepted to accommodate the members of Hyphodontia sensu lato. According to a further analysis of the ITS dataset, X. grandineus was retrieved as a sister to X. nesporii; X. punctus formed a monophyletic lineage and then grouped with X. filicinus, X. hastifer, X. hyphodontinus, and X. tropicus; and X. wenshanensis was a sister to X. xinpingensis.

A Phylogenetic and Taxonomic Study on Xylodon (Hymenochaetales): Focusing on Three New Xylodon Species from Southern China

Three wood-inhabiting fungal species, Xylodon laceratus, X. montanus, and X. tropicus spp. nov., were collected from southern China, here proposed as new taxa based on a combination of morphological features and molecular evidence. Xylodon laceratus is characterized by the resupinate basidiomata with grandinioid hymenophore having cracked hymenial surface, and ellipsoid basidiospores; X. montanus is characterized by the annual basidiomata having the hard, brittle hymenophore with cream hymenial surface, and ellipsoid to broadly ellipsoid basidiospores (3.9–5.3 × 3.2–4.3 µm); and X. tropicus is characterized by its grandinioid hymenophore with buff to a pale brown hymenial surface and subglobose basidiospores measuring 2–4.8 × 1.6–4 µm. Sequences of ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. The ITS+nLSU analysis of the order Hymenochaetales indicated that the three new species clustered into the family Schizoporaceae, located in genus Xylodon; based on further analysis of ITS dataset, X. laceratus was a sister to X. heterocystidiatus; X. montanus closely grouped with X. subclavatus and X. xinpingensis with high support; while X.tropicus was retrieved as a sister to X. hastifer.

Additions to the Knowledge of Corticioid Xylodon (Schizoporaceae, Hymenochaetales): Introducing Three New Xylodon Species from Southern China

Three wood-inhabiting fungal species, Xylodon gossypinus, X. macrosporus, and X. sinensis spp. nov. were collected from southern China, with the similar function to decompose rotten wood, which are here proposed as new taxa based on a combination of morphological features and molecular evidence. Xylodon gossypinus is characterized by the resupinate basidiomata with cotton hymenophore, and ellipsoid basidiospores; X.macrosporus is characterized by the resupinate basidiomata having the cracking hymenophore with pale yellowish hymenial surface, and larger basidiospores 8–10.5 × 7.5–9 µm; and X. sinensis differs by its grandinioid hymenial surface and subglobose basidiospores measuring as 3–5 × 2.5–4 µm. Sequences of ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. The ITS+nLSU analysis in Hymenochaetales revealed that the three new species clustered into the Schizoporaceae family, located in genus Xylodon; based on the ITS dataset, X. gossypinus was a sister to X. ussuriensis; X. macrosporus closely grouped with X.follis with a high support; and X.sinensis was retrieved as two sisters to X. attenuatus and X. yarraensis with a lower support.

The Hidden Wood-Decaying Fungal Diversity: Rhizochaete from East Asia

Wood-decaying fungi play crucial roles as decomposers in forest ecosystems. In this study, two new corticioid fungi, Rhizochaete fissurata and R. grandinosa spp. nov., are proposed based on a combination of morphological features and molecular evidence. Rhizochaete fissurata is characterized by resupinate basidiomata with a cracking hymenial surface, a monomitic hyphal system with simple-septa generative hyphae, presence of subfusiform to conical cystidia encrusted at the apex or coarse on the upper half, and ellipsoid basidiospores. Rhizochaete grandinosa differs in its resupinate basidiomata with a smooth hymenial surface, presence of two types of cystidia, and ellipsoid basidiospores. Sequences of ITS and nLSU rRNA markers of the studied samples were employed, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods on two datasets (ITS+nLSU and ITS). Both dataset analyses showed that two new species clustered into the genus Rhizochaete, in which, based on the ITS+nLSU dataset, R. fissurata was sister to R. belizensis, and R. grandinosa grouped with R. radicata; the phylogram inferred from ITS sequences inside Rhizochaete indicated that R. fissurata formed a monophyletic lineage with a lower support; R. grandinosa grouped closely with R. radicata. In addition, an identification key to all Rhizochaete species worldwide is provided.