Taxonomy and phylogeny of lignicolous freshwater fungi from plateau lakes in Yunnan Province, China

During the investigation of lignicolous freshwater fungi in plateau lakes in Yunnan Province, China, eight Lentitheciaceae species were collected from five lakes viz. Luguhu, Qiluhu, Xingyunhu, Cibihu, and Xihu lake. Based on morphological characters and phylogenetic analysis of combined ITS, LSU, SSU, and tef 1-α sequence data, a new genus Paralentithecium, two new species (Paralentithecium suae, and Setoseptoria suae), three new records (Halobyssothecium phragmitis, H. unicellulare, and Lentithecium yunnanensis) and three known species viz. Halobyssothecium aquifusiforme, Lentithecium pseudoclioninum, and Setoseptoria bambusae are reported.

Yunnan is one of the fungal diversity hotspots and many studies of lignicolous freshwater fungal research have been done in this Province. Presently, research on lignicolous freshwater fungi in the plateau lakes of this region is being systematically conducted. During our investigation of the species diversity of lignicolous freshwater fungi in Dujuanhu Lake, we found a distinctive species, Brachysporium sinense, based on morphological characteristics and phylogenetic analysis. Brachysporium sinense is distinguished from other Brachysporium species by monoblastic, integrated, terminal conidiogenous cells and fusoid to limoniform, verrucose, septate, brown to dark brown conidia with subhyaline ends, which are connected to the conidiogenous cells by a single denticle. Detailed descriptions and illustrations and relatively comprehensive sequence data are provided.

The shift from terrestrial to freshwater ecosystems is accompanied by a dramatic shift in the decomposer fungal assemblages. The life cycle of freshwater fungi complicates our understanding of the phylogenetic relationships in this group. The freshwater ascomycetes (teleomorphs) often have asexual states (referred to as anamorphs or mitosporic states) in their life cycles. The asexual states of freshwater ascomycetes are often adapted to aquatic life by producing spores (conidia) that are long and filamentous or branched; this facilitates their attachment to substrates in moving water. Some species have conidia that are tightly coiled to trap air or are hydrophobic and hollow; these adaptations allow them to float on the surface of water until they attach to a new substrate. The main ecological functions of freshwater fungi involve the breakdown of leaves, conifer needles, wood and other sources of coarse‐particulate organic matter. Training students in this field of fungi is imperative given the increase in global transportation of microbes, the rapid loss of healthy freshwater habitats due to human perturbation and global warming, the serious problem of antibiotic resistance and the rarity of trained taxonomists and molecular systematists in the field of mycology. Key Concepts Freshwater fungi are an ecological group of fungi and comprise both the meiosporic and mitosporic ascomycetes. They are important decomposers in freshwater habitats as they produce different types of enzymes to breakdown organic matter. The meiosporic ascomycetes are adapted to fresh water as their ascospores are equipped with gelatinous appendages or sheaths that are thought to help them attach to substrates in flowing or moving water. The mitosporic ascomycetes are adapted to freshwater habitats as they produce conidia, which are branched or long and filamentous, or have conidia which trap air for buoyancy and/or are hydrophobic. Freshwater fungi are understudied source of novel secondary metabolites. Phylogenetic studies on freshwater ascomycetes have shown that some species cluster with terrestrial ascomycete lineages while others belong in exclusive aquatic lineages. Distributional patterns of freshwater ascomycetes show distinct latitudinal and elevational structuring, but additional comparative studies are required to better predict distribution patterns of freshwater fungi. Species composition varies between lentic and lotic habitats, but more studies are warranted. Some species are distributed worldwide in similar habitats – A pantropical distribution of freshwater ascomycetes exists. As threats to freshwater biodiversity escalate, there is an urgent need to survey, collect and isolate freshwater fungal species, especially the poorly known but important taxa from the remaining high‐quality habitats. The knowledge of this group is essential to our understanding of ascomycete systematics in general as well as the systematics of freshwater ascomycete fungi.

Lignicolous freshwater fungi form a highly diverse group and are primarily distributed in the classes Dothideomycetes and Sordariomycetes. During an investigation of lignicolous freshwater fungi on the Tibetan Plateau, China, four collections were obtained from submerged wood in freshwater habitats. Morphological studies combined with multi-gene phylogenetic analysis based on ITS, LSU, SSU, and RPB2 indicated that the collected taxa belonged in the orders Conioscyphales and Cordanales in Sordariomycetes. Based on evidence from morpho-molecular analyses, two new species, Conioscypha xizangensis and Cordana linzhiensis, are introduced with descriptions of their hyphomycetous asexual states. Conioscypha xizangensis shows a close phylogenetic relationship with Conioscypha tenebrosa but, unlike that species, has phialidic and integrated conidiogenous cells. Cordana linzhiensis forms a distinct clade within the genus and possesses unique characteristics compared with existing species in having swollen conidiophores, polyblastic, clavate, or cylindrical conidiogenous cells, and solitary or acropleurogenous conidia with a hyaline mucoid sheath. These new discoveries further add to the diversity of freshwater fungi on the Tibetan Plateau.

During an investigation into species diversity of lignicolous freshwater fungi from the plateau lakes in Yunnan Province, China, a hyphomycetous fungus was collected from Dianchi Lake. The new isolate was placed in Appendopyricularia as a sister taxon of Appendopyricularia juncicola within Barbatosphaeriaceae based on the phylogenetic analysis of combined ITS and LSU sequence data. The fungus is characterized by acrogenous, fusoid, guttulate conidia that are 3–4 septate and have a flexuous central apical appendage. It exhibits more pronounced guttulate appendages and more prominent denticle sporulation structure. Therefore, Appendopyricularia guttulata is introduced as a new species based on morphological characteristics and phylogenetic evidence. The detailed description and illustrations of the new species are provided, as well as the morphological comparison with similar taxa.

During an investigation into lignicolous freshwater fungi from the plateau lakes in Yunnan Province, China, two fresh collections of Torula taxa were collected and examined morpholgically. Torulaluguhuensis is characterised by: conidiophores which are semi-macronematous mononematous, erect, septate, smooth, slightly flexuous and pale brown; conidiogenous cells which are holoblastic, mono- to polyblastic, integrated, terminal, terminal or intercalary in conidial chains, doliiform and pale brown; conidia which are branched chains, acrogenous, straight or slightly curved, dark brown to blackish, pale brown or subhyaline at apex, 1-3 septate, strongly constricted at the septa, verruculose or finely echinulate and rounded at both ends. A new species was introduced, based on morphological and phylogenetic analysis of combined ITS, LSU, RPB2 and TEF sequence data. Detailed descriptions and illustrations are provided, with an updated phylogenetic tree depicting intergeneric relationships within the Torulaceae.

Yuanjiang River (Red River) is one of the six major water systems in Yunnan Province, which originates from western Yunnan Province. This river system features numerous tributaries, complex terrain, and abundant natural resources. During the investigation on the diversity of lignicolous freshwater fungi in the Yuanjiang River, nine species were collected and identified, five belonging to Dothideomycetes and four to Sordariomycetes. Based on morphology and multigene phylogenetic analyses, four species, namely, Aquadictyospora aquatica, Dictyosporium fluminicola, Myrmecridium submersum, and Neomyrmecridium fusiforme, are described as new species. Dictyocheirospora aquadulcis is reported as a new national record, and Myrmecridium hydei is reported as a new habitat record. Dictyocheirospora rotunda, Halobyssothecium aquifusiforme, and Pseudohalonectria lutea were known earlier from freshwater habitats, but we described them in detail in this paper. This study contributes significantly to the understanding of the diversity of lignicolous freshwater fungi in southwestern China.

The diversity of lignicolous freshwater fungi in southwestern China is currently being studied. In this paper, two fungal isolates were collected from freshwater habitats in Yunnan Province, China. Based on morphological comparisons and the results of phylogenetic analysis of combined ITS, LSU, rpb2, SSU, and tef1-α sequence data, we introduce two new species, Aquadictyospora nujiangensis and Dendryphion verrucosum. Aquadictyospora nujiangensis is characterized by micronematous conidiophores and muriform, cheiroid conidia composed of compactly adpressed, curved rows of cells. Dendryphion verrucosum is characterized by erect, apically branched conidiophores, polytretic conidiogenous cells, and solitary or catenate to branched, monilioid conidia. This study contributes to the lignicolous freshwater fungal diversity in southwestern China.

Rainfall seasonality shapes microbial assembly and niche characteristics in Yunnan Plateau lakes, China

Lignicolous freshwater fungi from China Ⅳ: Morphology and phylogeny reveal new species of Pleosporales from plateau lakes in Yunnan Province, China

This paper reviews the filamentous, tropical freshwater fungi with special reference to those growing on submerged wood. The lignicolous freshwater fungi of Thailand, >236 species were observed (108 ascomycetes, 8 basidiomycetes, 120 anamorphic fungi). Three hundred and fourteen sporulated on maize meal agar medium (CMA) in a cooled illuminated cabinet and 21 telemorph-anamorph connections were established. Of the 236 freshwater fungi collected, 343 different strains were established (from 2400 single-spore isolates), of which 206 sporulated on CMA. Six of these have known connections with 4 previously reported terrestrial habitats: (1) Melanochaeta hemipsila with Sporochisma saccardoi; (2) Nectria chaetopsinae with Chaetopsina fulva; (3) N. chaetopsinae-polyblastiae with C. polyblastiae; and (4) Tubeufia cylindrothecia with Helicomyces roseus and two from freshwater habitats: (1) Ascotaiwania sawadae with Monotosporella anamorph stage; and (2) Hymenoscyphus varicosporoides with a Varicosporium anamorph stage. The study also showed that teleomorphs usually require prolonged incubation before they develop fully and mature on the substrata.

Pleurotheciaceae is a genera-rich and highly diverse family of fungi with a worldwide distribution in aquatic and terrestrial habitats. During the investigation of lignicolous freshwater fungi from karst landscapes in Yunnan Province, China, 15 fresh strains were obtained from submerged decaying wood. Based on the morphology and phylogenetic analysis of a combined LSU, ITS, SSU, and rpb2 sequence dataset, Obliquifusoideum triseptatum, Phaeoisaria obovata, Pleurotheciella brachyspora, Pl. longidenticulata, and Pl. obliqua were introduced as new species, P. synnematica and Rhexoacrodictys melanospora were reported as new habitat records, and P. sedimenticola and Pl. hyalospora were reported as new collections. In addition, based on morphological comparisons and phylogenetic analysis, we accepted Obliquifusoideum into in the family Pleurotheciaceae (Pleurotheciales, Savoryellomycetidae). Freshwater habitats are the primary habitats of Pleurotheciaceae species, and Yunnan Province has the highest concentration and species diversity of Pleurotheciaceae in China.

During the investigation of nematode-trapping fungi in Yunnan Province, four strains were isolated from the soil collected in Nujiang City, Yunnan Province, China and were identified as two new Arthrobotrys (Orbiliaceae) species based on morphology and multigene (ITS, EF1-α, and RPB2) phylogenetic analysis. Arthrobotrys gongshanensis is characterized by conidiophores producing 1–5 short denticles near the apex, bearing a single conidium on each denticle and obovoid to fusiform, 1–4-septate conidia. Arthrobotrys luzhangensis is characteristics by its obovoid to fusiform, 1–4-septate macroconidia, and clavate or obovoid, aseptate microconidia. These two new species both capture nematodes using adhesive networks. The multigene phylogenetic analyses further confirmed the taxonomic positions of these two new species within Arthrobotrys. This paper described them with illustrations and compared them with similar taxa.

Yunnan Province is one of the rich biodiversity hotspots with abundant resources of lignicolous freshwater fungi. A total of 281 species of lignicolous freshwater fungi from 1986 to the present in Yunnan Province. They are mostly distributed in the classes Dothideomycetes and Sordariomycetes, a few species in the Eurotiomycetes and Leotiomycetes, and rarely reported in Orbiliomycetes and Pezizomycetes. Lignicolous freshwater fungi can decompose lignocellulose substrates and release energy and nutrients, and thus playing an important role in freshwater environment. This study briefly reviewed the biodiversity and taxonomic status of lignicolous freshwater fungi in Yunnan, the ecological functions of lignicolous freshwater fungi, factors affecting community distribution, application status, and research difficulties.

In conducting a survey on the diversity of lignicolous freshwater fungi across a north-south latitudinal gradient in the Asian region, two strains were collected from freshwater habitats. This species is characterized by forming pinkish sporulating colonies both on wood and in culture, presenting macronematous conidiophores that swollen at the apex, producing cylindrical, pink in mass, 1-septate conidia, each with two flexuous, filamentous appendages arising from the middle of the cells. These characteristics closely match the definition of Hyphodiscosia. Through multigene phylogenetic analysis, this study for the first time determines the phylogenetic position of Hyphodiscosia within Muyocopronaceae (Muyocopronales). This study provides detailed illustrations, updates on molecular data, and a morphological comparison with related genera within Muyocopronaceae, as well as discusses the validity of the currently accepted four species within Hyphodiscosia.