Polyphyletic genera in Xylariaceae (Xylariales): Neoxylaria gen. nov. and Stilbohypoxylon

Multi-gene phylogenetic and taxonomic contributions to Xylaria (Ascomycota) associated with fallen fruits from China

Morphological and phylogenetic analyses on samples of Xylaria species associated with fallen fruits from China were carried out, and two new species were described, namely X.aleuriticola and X.microcarpa. Xylariaaleuriticola is found on fallen fruits of Aleuritesmoluccana, and characterized by stromata dichotomously branched several times with long acute sterile apices, fertile parts roughened with perithecia and tomentose, and ellipsoid to fusiform ascospores. Xylariamicrocarpa differs in its very small stromata with dark brown tomentum, light brown ascospores with an inconspicuous straight germ slit, and grows on leguminous pods. The differences between the new species and morphologically similar species are discussed. Phylogenetic analyses on ITS-RPB2-TUB sequences confirmed that the two species are clearly separated from other species of the genus Xylaria. Xylarialiquidambaris is reported as a new record from China. A key to the Xylaria species associated with fallen fruits and seeds reported from China is provided to facilitate future studies of the genus.

Study on endolichenic fungal assemblage in Parmotrema and Heterodermia lichens of Shivamoga, Karnataka

BACKGROUND

Lichen is a symbiotic association of algae and fungi, recognized as a self-sustaining ecosystem that constitutes an indeterminant number of bacteria, actinomycetes, fungi, and protozoa. We evaluated the endolichenic fungal assemblage given the dearth of knowledge on endolichenic fungi (ELFs), particularly from part of the Central Western Ghats, Karnataka, and conducted a phylogenetic analysis of xylariaceous fungi, the most diversified group of fungi using ITS and ITS+Tub2 gene set.

RESULTS

Out of 17 lichen thalli collected from 5 ecoregions, 42 morphospecies recovered, belong to the class Sordariomycetes, Eurotiomycetes, Dothideomycetes, Leotiomycetes, Saccharomycetes. About 19 and 13 ELF genera have been reported from Parmotrema and Heterodermia thallus. Among the ecoregions EC2 showing highest species diversity (Parmotrema (1-D) = 0.9382, (H) = 2.865, Fisher-α = 8.429, Heterodermia (1-D) = 0.8038, H = 1.894, F-α = 4.57) followed the EC3 and EC1. Xylariales are the predominant colonizer reported from at least one thallus from four ecoregions. The morphotypes ELFX04, ELFX05, ELFX08 and ELFX13 show the highest BLAST similarity (> 99%) with Xylaria psidii, X. feejeensis, X. berteri and Hypoxylon fragiforme respectively. Species delimitation and phylogenetic position reveal the closest relation of Xylariaceous ELFs with plant endophytes.

CONCLUSIONS

The observation highlights that the deciduous forest harness a high number of endolichenic fungi, a dominant portion of these fungi are non-sporulating and still exist as cryptic. Overall, 8 ELF species recognized based on phylogenetic analysis, including the two newly reported fungi ELFX03 and ELFX06 which are suspected to be new species based on the present evidence. The study proved, that the lichen being rich source to establish fungal diversity and finding new species. Successful amplification of most phylogenetic markers like RPB2, building of comprehensive taxonomic databases and application of multi-omics data are further needed to understand the complex nature of lichen-fungal symbiosis.

Morphology and multigene phylogeny reveal three new species of Distoseptispora (Distoseptisporales, Distoseptisporaceae) on palms (Arecaceae) from peatswamp areas in southern Thailand

Peatswamp forest is a unique habitat that supports high biodiversity, particularly fungal diversity. The current study collected submerged and dead plant parts from Eleiodoxaconferta, Eugeissonatristis and Licualapaludosa from a peatswamp forest in Narathiwat Province, Thailand. Morphological features coupled with multigene phylogenetic analyses of ITS, LSU, rpb2 and tef1-α sequence data identified our isolates as new Distoseptispora species (viz. D.arecacearumsp. nov., D.eleiodoxaesp. nov. and D.narathiwatensissp. nov.). Morphological descriptions, illustrations and notes are provided.

Appressoria-Producing Sordariomycetes Taxa Associated with Jasminum Species

Appressoria are specialized structures formed by certain phytopathogenic fungi during the early stages of the infection process. Over the years, significant advancements have been made in understanding the formation, types, and functions of appressoria. Besides being formed primarily by fungal pathogens, many studies have reported their occurrence in other life modes such as endophytes, epiphytes, and saprobes. In this study, we observed the formation of appressoria in fungal genera that have been found associated with leaf spots and, interestingly, by a saprobic species. We used morphological descriptions and illustrations, molecular phylogeny, coalescent-based Poisson tree processes (PTP) model, inter- and intra-species genetic distances based on their respective DNA markers, and Genealogical Concordance Phylogenetic Species Recognition Analysis (GCPSR) to establish a new species (Pseudoplagiostoma jasmini), a Ciliochorella sp., and a new host record (Coniella malaysiana). The Ciliochorella sp. is reported as a saprobe, while Pseudoplagiostoma jasmini and Coniella malaysiana were found to be associated with leaf spots of Jasminum species. All three taxa produce appressoria, and this is the first study that reports the formation of appressoria by a Ciliochorella sp. and a Pseudoplagiostoma sp.

Palm Fungi and Their Key Role in Biodiversity Surveys: A Review

Over the past three decades, a wealth of studies has shown that palm trees (Arecaceae) are a diverse habitat with intense fungal colonisation, making them an important substratum to explore fungal diversity. Palm trees are perennial, monocotyledonous plants mainly restricted to the tropics that include economically important crops and highly valued ornamental plants worldwide. The extensive research conducted in Southeast Asia and Australasia indicates that palm fungi are undoubtedly a taxonomically diverse assemblage from which a remarkable number of new species is continuously being reported. Despite this wealth of data, no recent comprehensive review on palm fungi exists to date. In this regard, we present here a historical account and discussion of the research on the palm fungi to reflect on their importance as a diverse and understudied assemblage. The taxonomic structure of palm fungi is also outlined, along with comments on the need for further studies to place them within modern DNA sequence-based classifications. Palm trees can be considered model plants for studying fungal biodiversity and, therefore, the key role of palm fungi in biodiversity surveys is discussed. The close association and intrinsic relationship between palm hosts and palm fungi, coupled with a high fungal diversity, suggest that the diversity of palm fungi is still far from being fully understood. The figures suggested in the literature for the diversity of palm fungi have been revisited and updated here. As a result, it is estimated that there are about 76,000 species of palm fungi worldwide, of which more than 2500 are currently known. This review emphasises that research on palm fungi may provide answers to a number of current fungal biodiversity challenges.

Exploring the Xylariaceae and its relatives

The Xylariaceae and its relatives rank as one of the best-known members of the Ascomycota. They are now well recognized for their diversity, global distribution, ecological activities and their outstanding novel metabolites with wide ranging bioactivity.

Studies on the secondary metabolism of Rosellinia and Dematophora strains (Xylariaceae) from Iran

The xylariaceous genus Dematophora has recently been resurrected and segregated from Rosellinia based on a molecular phylogeny and morphological characters. This was an important taxonomic change because Dematophora in the current sense contains several important pathogens, while Rosellinia is limited to mainly saprotrophic species that have an endophytic stage in their life cycle and may even have beneficial effects on the host plants. During our ongoing work on the functional biodiversity of the Xylariales, we have encountered new strains of rosellinoid Xylariaceae from Iran and have studied their mycelial cultures for secondary metabolites in an attempt to establish further chemotaxonomic affinities. In the process, we isolated and identified 13 compounds, of which rosellisteroid (1), the cichorine derivative 2, and the alkaloid 3 are new. Out of these, nine were tested for their antimicrobial affinities with cytochalasin E (6) exhibiting weak activity against Schizosaccharomyces pombe. The cytotoxicity of three cytochalasin derivatives was examined and their effects on the F-actin cytoskeletal organization studied by fluorescence microscopy using fluorescent phalloidin. Cytochalasin E (6) and Δ6,12-cytochalasin E (7) showed strong and irreversible action on actin, while cytochalasin K (8) exhibited weaker, reversible effects.

Multigene Phylogeny Reveals Endophytic Xylariales Novelties from Dendrobium Species from Southwestern China and Northern Thailand

Xylariales are common endophytes of Dendrobium. However, xylarialean species resolution remains difficult without sequence data and poor sporulation on artificial media and asexual descriptions for only several species and old type material. The surface-sterilized and morph-molecular methods were used for fungal isolation and identification. A total of forty-seven strains were identified as twenty-three species belonging to Apiosporaceae, Hypoxylaceae, Induratiaceae, and Xylariaceae. Five new species—Annulohypoxylon moniliformis, Apiospora dendrobii, Hypoxylon endophyticum, H. officinalis and Nemania dendrobii were discovered. Three tentative new species were speculated in Xylaria. Thirteen known fungal species from Hypoxylon, Nemania, Nigrospora, and Xylaria were also identified. Another two strains were only identified at the genus and family level (Induratia sp., Hypoxylaceae sp.). This study recorded 12 new hosts for xylarialean endophytes. This is the first report of Xylariales species as endophytes from Dendrobium aurantiacum var. denneanum, D. cariniferum, D. harveyanum, D. hercoglossum, D. moniliforme, and D. moschatum. Dendrobium is associated with abundant xylarialean taxa, especially species of Hypoxylon and Xylaria. We recommend the use of oat agar with low concentrations to induce sporulation of Xylaria strains.

Predicting global numbers of teleomorphic ascomycetes

Sexual reproduction is the basic way to form high genetic diversity and it is beneficial in evolution and speciation of fungi. The global diversity of teleomorphic species in Ascomycota has not been estimated. This paper estimates the species number for sexual ascomycetes based on five different estimation approaches, viz. by numbers of described fungi, by fungus:substrate ratio, by ecological distribution, by meta-DNA barcoding or culture-independent studies and by previous estimates of species in Ascomycota. The assumptions were made with the currently most accepted, “2.2–3.8 million” species estimate and results of previous studies concluding that 90% of the described ascomycetes reproduce sexually. The Catalogue of Life, Species Fungorum and published research were used for data procurement. The average value of teleomorphic species in Ascomycota from all methods is 1.86 million, ranging from 1.37 to 2.56 million. However, only around 83,000 teleomorphic species have been described in Ascomycota and deposited in data repositories. The ratio between described teleomorphic ascomycetes to predicted teleomorphic ascomycetes is 1:22. Therefore, where are the undiscovered teleomorphic ascomycetes? The undescribed species are no doubt to be found in biodiversity hot spots, poorly-studied areas and species complexes. Other poorly studied niches include extremophiles, lichenicolous fungi, human pathogens, marine fungi, and fungicolous fungi. Undescribed species are present in unexamined collections in specimen repositories or incompletely described earlier species. Nomenclatural issues, such as the use of separate names for teleomorph and anamorphs, synonyms, conspecific names, illegitimate and invalid names also affect the number of described species. Interspecies introgression results in new species, while species numbers are reduced by extinctions.

Twelve New Taxa of Xylaria Associated with Termite Nests and Soil from Northeast Thailand

Simple Summary

Xylaria species are known for their medicinal value and production of a variety of bioactive compounds. They usually grow on rotten wood, fallen leaves, seeds, and fruits. Some species can be found growing on soil or associated with termite nests, which belong to subgenus Pseudoxylaria. They share with other Xylaria species a suite of morphological characteristics, including conspicuous or massive upright stromata with a light-coloured interior, a longer than wide ascal apical ring, bluing in an iodine reagent, and brown unicellular ascospores possessing a germ slit. In Thailand, there are only limited reports on Xylaria diversity and taxonomy, especially on species associated with termite nests. In the present study, we describe 12 new Xylaria taxa and report two species closely resembling known species from termite nests or soil. Their morphological and cultural characteristics are described and illustrated, and their nucleotide sequences of ITS rDNA, alpha-actin, and beta-tubulin genes were obtained. Phylogenetic inference based on these sequences confirmed that all taxa analyzed belong to subgenus Pseudoxylaria and differ from all other species with sequences available in public databases. Our study is the first to report on the novel Xylaria species associated with termite nests or growing on soil in Thailand. Subgenus Pseudoxylaria is likely highly diverse in the country.

Abstract

The diversity of Xylaria species associated with termite nests in northeast Thailand was investigated. Among the 14 taxa included in this study, 11 species and one variety were described as new, and another two species resemble the existing taxa, X. escharoidea and X. nigripes. The newly described taxa are X. chaiyaphumensis, X. conica, X. fulvescens, X. ischnostroma, X. margaretae, X. minima, X. reinkingii var. microspora, X. siamensis, X. sihanonthii, X. subintraflava, X. thienhirunae, and X. vinacea. Their morphological and cultural characteristics are described and illustrated, and their ITS, α-actin and β-tubulin sequences were analysed. A dichotomous key to the 17 species of Xylaria occurring in Thailand is provided.

Multigene Phylogeny Reveals Haploanthostomella elaeidis gen. et sp. nov. and Familial Replacement of Endocalyx (Xylariales, Sordariomycetes, Ascomycota)

During our investigation of palm fungi in Thailand, two interesting taxa from Elaeis guineensis and Metroxylon sagu (Arecaceae) were collected. Based on phylogenetic analyses of a combined dataset of ITS, LSU, rpb2, and tub2 nucleotide sequences as well as unique morphological characteristics, we introduce the new genus Haploanthostomella within Xylariales, and a new species Endocalyx metroxyli. Additionally, in our study, the genus Endocalyx is transferred to the family Cainiaceae based on its brown conidia and molecular phylogenetic evidence.