Bearing Clamp Connections Research Articles

A new species of Fomes (Polyporaceae, Basidiomycota) from southwestern China

The species diversity of Fomes in China has not been well studied, and all Fomes samples were previously identified as Fomes fomentarius based on morphology. Recent phylogenetic and morphological analyses on Fomes were carried out and one new species from Yunnan Province of southwest China, Fomes hengduanensis, was discovered. F. hengduanensis is characterized by perennial, pileate basidiomata with small ungulate pilei, greyish brown, fawn to dark grey, concentrically zonate and sulcate upper surface, greyish brown pore surface when fresh, distinct sterile margin, a trimitic hyphal system bearing clamp connections on generative hyphae, clavate to fusoid cystidioles, cylindrical basidiospores measuring 9.5–14 × 4.5–7 µm, and growing on Quercus semecarpifolia in montane forest. It differs from the most common species F. fomentarius by smaller basidiospores (9.5–14 × 4.5–7 µm vs. 15–21 × 5–7 µm), and also differs by the DNA sequences. We present the new species with illustrated description, molecular work and comparison with morphologically similar or related species.

Luteoporia tenuissima sp. nov. (Polyporales, Basidiomycota), evidenced by morphological characteristics and phylogenetic analysis

A new poroid wood-inhabiting fungus in the Polyporales, Luteoporia tenuissima, from southwest China, is described based on morphological and molecular evidence. Luteoporia tenuissima is characterized by annual, resupinate basidiomata with lemon chrome pores when fresh, becoming cinnamon buff when dry, tissues becoming purple in KOH, a monomitic hyphal system, generative hyphae thick-walled and bearing clamp connections, and ellipsoid, smooth basidiospores measuring 2.9–3.8 × 1.9–2.4 µm. The phylogenetic analysis based on ITS + nLSU rDNA sequences shows that the new species belongs to Luteoporia, forming a monophyletic lineage with strong support, clustering with L. albomarginata and L. citriniporia. Both morphological characteristics and molecular phylogeny confirm the placement of the new species within the genus Luteoporia. A full description, illustration, phylogeny of the new species, and comparisons with morphologically similar or phylogenetically related species are provided. In addition, an identification key is provided for the currently known Luteoporia species.

Two new species of Haploporus (Polyporales, Basidiomycota) from China and Ecuador based on morphology and phylogeny.

At present, 25 species are accepted in Haploporus and are distributed in Asia, Europe, North America, South America, Australia, and Africa. In this study, two new species, Haploporus ecuadorensis from Ecuador and H. monomitica from China, are described and illustrated based on morphological examination and phylogenetic analyses. H. ecuadorensis is characterized by annual, resupinate basidiomata with pinkish buff to honey yellow hymenophore when dry, round to angular pores of 2-4 per mm, a dimitic hyphal structure with generative hyphae bearing clamp connections, hyphae at dissepiment edge usually with one or two simple septa, the presence of dendrohyphidia and cystidioles, and oblong to ellipsoid basidiospores measuring 14.9-17.9 × 6.9-8.8 µm. Haploporus monomitica differs from other Haploporus species in that it has a monomitic hyphal system and strongly dextrinoid basidiospores. The differences between the new species and morphologically similar and phylogenetically related species are discussed. In addition, an updated key to 27 species of Haploporus is provided.

Ramaricium yunnanense sp. nov. (Gomphaceae, Gomphales) from China

A new corticioid fungus belonging to Ramaricium is described from China based on morphology and molecular phylogenetic analyses. It is characterized by annual, resupinate basidiomata with a white hymenial surface, a monomitic hyphal system with generative hyphae bearing clamp connections, and ellipsoid to subglobose basidiospores with thin, colorless, ornamented walls. Phylogenetic analyses of combined internal transcribed spacer (ITS) and large subunit nuclear ribosomal RNA gene (nLSU) regions showed that the corticioid fungus is a distinct species in Ramaricium and nested sister to R. polyporoideum. The new corticioid fungus is described and named as Ramaricium yunnanense in this study. A full description, illustration, and a phylogenetic tree to show the placement of Ramaricium yunnanense sp. nov. are provided.

Outline, Divergence Times, and Phylogenetic Analyses of Trechisporales (Agaricomycetes, Basidiomycota).

Phylogenetic analyses inferred from the nuc rDNA ITS1-5.8S-ITS2 (ITS) data set and the combined 2-locus data set [5.8S + nuc 28S rDNA (nLSU)] of taxa of Trechisporales around the world show that Sistotremastrum family forms a monophyletic lineage within Trechisporales. Bayesian evolutionary and divergence time analyses on two data sets of 5.8S and nLSU sequences indicate an ancient divergence of Sistotremastrum family from Hydnodontaceae during the Triassic period (224.25 Mya). Sistotremastrum family is characterized by resupinate and thin basidiomata, smooth, verruculose, or odontoid-semiporoid hymenophore, a monomitic hyphal structure, and generative hyphae bearing clamp connections, the presence of cystidia and hyphidia in some species, thin-walled, smooth, inamyloid, and acyanophilous basidiospores. In addition, four new species, namely, Trechispora dentata, Trechispora dimitiella, Trechispora fragilis, and Trechispora laevispora, are described and illustrated. In addition, three new combinations, namely, Brevicellicium daweishanense, Brevicellicium xanthum, and Sertulicium limonadense, are also proposed.

Global Diversity and Taxonomy of Sidera (Hymenochaetales, Basidiomycota): Four New Species and Keys to Species of the Genus.

The genus Sidera is a polypore genus with resupinate, white to cream or buff fresh basidioma, poroid or hydnoid hymenophore, a monomitic or dimitic hyphal system with generative hyphae bearing clamp connections, the presence of rosette-like crystals and allantoid to lunate basidiospores. We study the phylogeny and diversity of Sidera herein by using both morphological and molecular methods. Phylogenetic analyses are based on the ITS dataset, the combined 2-locus dataset (5.8S + nLSU) and 7-locus dataset (ITS + nLSU + RPB1 + RPB2 + TEF1 + mtSSU + nSSU) of 15 taxa of Sidera all over the world. Among them, four species are new to science and described and illustrated in this paper, viz. S. inflata, S. malaysiana, S. punctata and S. roseo-bubalina. In addition, three taxa were treated as Sidera vulgaris sensu lato. An identification key of the 14 accepted species of Sidera worldwide is provided.

Hyphoderma fissuratum and H. mopanshanense spp. nov. (Polyporales) from southern China.

Two new species, Hyphoderma fissuratum and H. mopanshanense spp. nov., are proposed based on morphological and molecular evidences. Hyphoderma fissuratum is characterized by resupinate basidiomata with cracking hymenial surface, a monomitic hyphal system with generative hyphae bearing clamp connections, IKI-, CB-, and cylindrical, colorless, thin-walled, smooth basidiospores measuring (8.5-10.3 × 3-4 µm). Hyphoderma mopanshanense is characterized by an annual growth habit, slight gray to cream hymenial surface, and fusiform, thick-walled cystidia apically encrusted with crystal. Sequences of ITS and LSU nrRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony and Bayesian inference methods. These phylogenetic analyses based on molecular data of ITS and nLSU sequences showed that two Hyphoderma new species formed a well supported monophyletic lineage distinct from other related species and then H. fissuratum grouped with H. medioburiense and H. roseocremeum. Hyphoderma mopanshanense grouped with H. setigerum.

Steccherinum tenuissimum and S. xanthum spp. nov. (Polyporales, Basidiomycota): New species from China.

Two new wood-inhabiting fungal species, Steccherinum tenuissimum and S. xanthum spp. nov. are described based on a combination of morphological features and molecular evidence. Steccherinum tenuissimum is characterized by an annual growth habit, resupinate basidiomata with an odontioid hymenial surface, a dimitic hyphal system with clamped generative hyphae, strongly encrusted cystidia and basidiospores measuring 3–5 × 2–3.5 μm. Steccherinum xanthum is characterized by odontioid basidiomata and a monomitic hyphal system with generative hyphae bearing clamp connections and covering by crystals, colourless, thin-walled, smooth, IKI–, CB–and has basidiospores measuring 2.7–5.5 × 1.8–4.0 μm. Sequences of the ITS and nLSU nrRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony and Bayesian inference methods. The phylogenetic analyses based on molecular data of ITS + nLSU sequences showed that two new Steccherinum species felled into the residual polyporoid clade. Further investigation was obtained for more representative taxa in Steccherinum based on ITS + nLSU sequences, which demonstrated that S. tenuissimum and S. xanthum were sister to S. robustius with high support (100% BP, 100% BS and 1.00 BPP).

<p><strong><em>Peniophorella cremea sp. nov.</em></strong><strong> from China</strong></p>

A new wood-inhabiting fungal species, Peniophorella cremea sp. nov. is proposed based on a combination of morphological features and molecular evidence. Peniophorella cremea is characterized by an annual growth habit, resupinate basidiomata with odontioid hymenial surface, a monomitic hyphal system with generative hyphae bearing clamp connections and ellipsoid, hyaline, thin-walled, smooth basidiospores measuring as 7–9.5 × 2.7–3.3 µm. The phylogenetic analyses based on ITS sequences showed that P. cremea forms a monophyletic lineage with high statistical supports (100% BS, 100% BP and 1.00 BPP).

WITHDRAWN: Hyphoderma fissuratum and H. mopanshanense spp. nov. (Polyporales) from southern China

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<p><strong>A new species of <em>Wrightoporia</em> (Wrightoporiaceae, Basidiomycota) from Sri Lanka</strong></p>

A new resupinate polypore, Wrightoporia srilankensis sp. nov., is described from Sri Lanka. It is characterized by annual resupinate basidiocarps with buff yellow pores, margin and subiculum with rhizomorphs, a dimitic hyphal structure with yellowish crystals on both generative and skeletal hyphae, generative hyphae bearing clamp connections, dextrinoid and cyanophilous skeletal hyphae, the absence of gloeoplerous hyphae and gloeocystidia, and broadly ellipsoid, hyaline, thick-walled, finely asperulate, strongly amyloid, cyanophilous basidiospores measuring 3.8–4.2 × 2.8–3.2 µm. Molecular phylogenetic analyses based on ITS and nLSU rDNA sequences confirmed that W. srilankensis nested in the Wrightoporia clade. W. srilankensis is closely related to Wrightoporia avellanea which, however, lacks cystidioles, and its hyphae are smooth (without crystals).

Rhomboidia wuliangshanensis gen. & sp. nov. from southwestern China

A new, white-rot, poroid, wood-inhabiting fungal genus, Rhomboidia, typified by R. wuliangshanensis, is proposed based on morphological and molecular evidence. Collected from subtropical Yunnan Province in southwest China, Rhomboidia is characterized by annual, stipitate basidiomes with rhomboid pileus, a monomitic hyphal system with thick-walled generative hyphae bearing clamp connections, and broadly ellipsoid basidiospores with thin, hyaline, smooth walls. Phylogenetic analyses of ITS and LSU nuclear RNA gene regions showed that Rhomboidia is in Steccherinaceae and formed as distinct, monophyletic lineage within a subclade that includes Nigroporus, Trullella, and Flabellophora .

<p><strong><em>Trechispora yunnanensis</em></strong><strong> <em>sp. nov.</em> (Hydnodontaceae, Basidiomycota) from China</strong></p>

A new wood-inhabiting fungal species, Trechispora yunnanensis sp. nov., is proposed based on morphological characteristics and molecular phylogenetic analyses. The species is characterized by resupinate basidiomata, rigid and fragile up on drying, cream to pale greyish hymenial surface; a monomitic hyphal system with generative hyphae bearing clamp connections, IKI-, CB-; ellipsoid, hyaline, thick-walled, ornamented, IKI-, CB- basidiospores measuring as 7–8.5 × 5–5.5 µm. The internal transcribed spacer (ITS) and the large subunit (LSU) regions of nuclear ribosomal RNA gene sequences of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood (ML), maximum parsimony (MP) and bayesian inference methods (BPP). The phylogenetic analyses based on molecular data of ITS+nLSU sequences showed that T. yunnanensis formed a monophyletic lineage with a strong support (100% ML, 100% MP, 1.00 BPP) and was closely related to T. byssinella and T. laevis. Both morphological characteristics and results of molecular phylogenetic analyses confirmed the placement of the new species in Trechispora.

Xylodon kunmingensis sp. nov. (Hymenochaetales, Basidiomycota) from southern China

Abstract A new wood-inhabiting fungal species, Xylodon kunmingensis, is proposed based on morphological and molecular evidences. The species is characterized by an annual growth habit, resupinate basidiocarps with cream to buff hymenial, odontioid surface, a monomitic hyphal system with generative hyphae bearing clamp connections and oblong-ellipsoid, hyaline, thin-walled, smooth, inamyloid and indextrinoid, acyanophilous basidiospores, 5–5.8 × 2.8–3.5 μm. The phylogenetic analyses based on molecular data of ITS sequences showed that X. kunmingensis belongs to the genus Xylodon and formed a single group with a high support (100% BS, 100% BP, 1.00 BPP) and grouped with the related species X. astrocystidiatus, X. crystalliger and X. paradoxus. Both morphological and molecular evidences confirmed the placement of the new species in Xylodon.

Multitrophic interactions in a geothermal setting: Arthropod borings, actinomycetes, fungi and fungal-like microorganisms in a decomposing conifer wood from the Jurassic of Patagonia

A permineralized araucarioid conifer stem, preserved in state of partial decay, is described from the Middle to Late Jurassic Chon-Aike Formation (Bahía Laura Group) at Laguna Flecha Negra, in the Deseado Massif, Santa Cruz Province, Argentina. The tree-stem, which comprises periderm to the secondary xylem, shows evidence of interactions with xylophagous borers, fungi, actinomycetes and other fungal-like microorganisms. In the secondary phloem, it displays rows of traumatic resin ducts, which host abundant mycelium comprising very thin hyphae differentiated into spore-producing structures comparable to actinomycete bacteria and spherical fungal-like resting structures. In the cortical and phloem regions, there are cell groups with structural changes, which appear variably degraded by fungi. The secondary xylem displays decay of cellulose and lignified components, at various spatial scales, comparable with fungal decay patterns in modern wood. Further septate fungal filaments, sometimes bearing clamp connections are associated with decayed regions. The degraded secondary xylem shows circular to oval borings filled with frass containing degraded tracheids, comparable to those bored by different wood boring beetles. Development of traumatic resin ducts in the phloem could have been triggered by penetration of the living stem by these xylophagous arthropods. The association of the different components present suggests pathogenic and saprotrophic interactions promoting decomposition of the stem, and represents a rarely-documented example of multitrophic biological interactions involving several different biological groups in Jurassic terrestrial paleoecosystems.

First Report of Sclerotium rolfsii Causing Stem Rot of Luffa cylindrica in Brazil

Luffa cylindrica (L.) Roem. (Cucurbitaceae) is an Asian vine widely known as the source of loofah (Purseglove 1968). In Brazil (local name bucha), it is cultivated by small-scale producers as a cash crop. In February 2017, L. cylindrica plants with rotted and girdled stem bases were found in a commercial field (27°22′S; 53°25′W) in Frederico Westphalen, Rio Grande do Sul, Brazil. Disease symptoms later led to a collapse of stems. Necrotic areas were covered with white cotton mycelium as well as abundant spherical sclerotia. The fungus was isolated in pure culture by direct transfer of sclerotia in aseptic plates with potato dextrose agar (PDA). After 7 days, cottony white colonies started to appear, often forming fans, primary hyphae 2.0 to 5.0 μm in diameter, and bearing clamp connections; sclerotia formed after 10 days, initially white and becoming dark brown with age, and 0.65 to 2.15 mm in diameter. A specimen was deposited in the herbarium (Federal University of Pelotas Herbarium, Rio Grande do Sul State, Brazil) under accession no. LPS0025. Molecular characterization was performed by amplifying and sequencing the internal transcribed spacer (ITS) region using ITS1 and ITS4 primers (White et al. 1990) and the translation elongation factor (TEF-1α) gene region using primers EF595F and EF1160R (Wendland and Kothe 1997). Sequences of the studied DNA regions were submitted to GenBank (ITS: MF425542; and TEF-1α: MF434828). BLAST searches in GenBank showed 99 to 100% identity with the existing sequences of Athelia rolfsii (Curzi) C. C. Tu & Kimbr (anamorph: Sclerotium rolfsii Sacc.) (ITS: KU128903, KX139196, DQ059578, and GU080230; and TEF-1α: KM521767, JF267808, JF267798, and JF267798). To fulfill Koch’s postulates, 10 healthy, 20-day-old L. cylindrica seedlings were inoculated with sclerotia obtained from a 15-day-old culture. Dry sclerotia were placed directly at the base of the plant (four sclerotia per plant). Ten uninoculated L. cylindrica seedlings were used as the control treatment. The inoculated and uninoculated plants were incubated in a humid growth at 26°C for 24 h and then maintained in a greenhouse. Seven days later, pathogen-inoculated plants showed typical symptoms similar to those observed under natural conditions, but no symptoms were seen on the control plants. The pathogenicity tests were carried out three times. The fungus was reisolated from the artificially inoculated plants. According to morphological and molecular characteristic combinations, the isolate was confirmed as S. rolfsii. S. rolfsii has been reported on Citrullus lanatus, Cucumis sativus, Cucurbita pepo, and other species in the Cucurbitaceae family in Brazil (Queiroz et al. 2002), but not on Luffa cylindrica. To our knowledge, this is the first report of S. rolfsii causing disease on L. cylindrica in Brazil.

Leifiporia rhizomorpha gen. et sp. nov. and L. eucalypti comb. nov. in Polyporaceae (Basidiomycota)

A new poroid wood-inhabiting fungal genus, Leifiporia, is proposed, based on morphological and molecular evidence, which is typified by L. rhizomorpha sp. nov. The genus is characterized by an annual growth habit, resupinate basidiocarps with white to cream pore surface, a dimitic hyphal system with generative hyphae bearing clamp connections and branching mostly at right angles, skeletal hyphae present in the subiculum only and distinctly thinner than generative hyphae, IKI–, CB–, and ellipsoid, hyaline, thin-walled, smooth, IKI–, CB– basidiospores. Sequences of ITS and LSU nrRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony and Bayesian inference methods. The phylogenetic analysis based on molecular data of ITS + nLSU sequences showed that Leifiporia belonged to the core polyporoid clade and was closely related to Diplomitoporus overholtsii and Lopharia cinerascens, and then grouped with Pycnoporus and Trametes. Further investigation was obtained for more representative taxa in the Polyporaceae based on nLSU sequences, in which the results demonstrated that the genus Leifiporia formed a monophyletic lineage with a strong support (100 % BS, 100 % BP, 1.00 BPP). Both morphological and molecular evidence confirmed the placement of the new genus in the core polyporoid clade. In addition, a new combination, Leifiporia eucalypti, is proposed based on examination of its type material and phylogeny.

Sclerotium rolfsii Causing Stem Rot of Impatiens walleriana in Brazil.

Impatiens walleriana, busy lizzy or balsam (local names in Brazil maria-sem-vergonha or beijo-de-frade), is an African member of the Balsaminaceae that has long ago been introduced and established in Brazil. It is now widely cultivated commercially as a potted plant and a popular garden plant (3). It also is a common weed along the coast and is particularly troublesome in some banana plantation areas. There are only two records of fungal pathogens attacking this plant in Brazil: Cercospora fukushiana (leaf spot) and Oidiopsis haplophylli (powdery mildew). In January 2009, a population of diseased plants of I. walleriana was found in a private garden in the city of Rio de Janeiro, Brazil. Plants had rotted and girdled stem bases, leading to a collapse of stems Necrotic areas were covered with fans of white mycelium as well as abundant spherical sclerotia. The fungus was isolated in pure culture by direct aseptic transfer of mycelial fragments and sclerotia to potato dextrose agar (PDA) plates. Colonies were white, cottony, often forming fans, primary hyphae 3.0 to 6.0 μm in diameter, and bearing clamp connections; sclerotia formed after 7 days, initially white becoming dark brown with age, and 0.8 to 1.85 mm in diameter. These are typical features of Sclerotium rolfsii. A specimen was deposited in the local herbarium (Herbarium VIC) under Accession No. VIC 30732. Koch's postulates were performed by inoculating three healthy potted I. walleriana plants (10 × 40 cm high) with approximately 100 freshly collected sclerotia placed in close vicinity with the stem bases. Noninoculated plants kept in a separate pot served as controls. Plants were incubated in a dew chamber for 48 h at 25 ± 2°C. All inoculated plants showed symptoms of stem rot 72 h after inoculation, whereas controls remained healthy. S. rolfsii is a highly polyphagous species that has been recorded to be causing rots (also known as Southern blights) in Brazil on numerous hosts but there are no records of it attacking any members of the Balsaminaceae in Brazil. The only other published records of S. rolfsii on Impatiens spp. are from the United States (Hawaii and Illinois) (2) and the Philippines (1). In South America, there is a single report from Argentina (4) where the disease is regarded as a major threat to the potted plant industry because I. walleriana is one of the most popular potted plants in that country. The potential for losses is also significant for Brazil. To our knowledge, this is the first report of S. rolfsii as a pathogen of I. walleriana in Brazil. Although very damaging to I. walleriana, it is unlikely that this fungus can be used as a natural enemy of this plant species in weed situations because of its wide host range.

Isolation of a homothallic mutant in Lentinula edodes

To obtain a homothallic mutant in Lentinula edodes, basidiospores derived from the common Bmut dikaryon (A1B1mut × A2B1mut) were treated with UV irradiation. Of a total of approximately 5000 monosporous cultures recovered, a single basidiospore isolate was found to produce the hyphae bearing clamp connections without mating. This mutant strain could form fruit bodies, and all its single basidiospore isolates developed into colonies with clamp connections. Such homothallic behaviors were transmitted from the mutant strain to the next generation. During the germination and following hyphal elongation in a single basidiospore of mutant strain, clamp connections were clearly detected in multicellular hyphae, which contained two nuclei in each cell. Their clamp connections were morphologically variable, viz., pseudo, abnormal, and true clamps. Amplified fragment length polymorphism (AFLP) profiles among the basidiospore isolates of mutant strain were identical, indicating that the mutant strain produced isogenic basidiospore progeny.

Isolation of a homothallic mutant in <i>Lentinula edodes</i>

To obtain a homothallic mutant in Lentinula edodes, basidiospores derived from the common Bmut dikaryon (A1B1mut × A2B1mut) were treated with UV irradiation. Of a total of approximately 5000 monosporous cultures recovered, a single basidiospore isolate was found to produce the hyphae bearing clamp connections without mating. This mutant strain could form fruit bodies, and all its single basidiospore isolates developed into colonies with clamp connections. Such homothallic behaviors were transmitted from the mutant strain to the next generation. During the germination and following hyphal elongation in a single basidiospore of mutant strain, clamp connections were clearly detected in multicellular hyphae, which contained two nuclei in each cell. Their clamp connections were morphologically variable, viz., pseudo, abnormal, and true clamps. Amplified fragment length polymorphism (AFLP) profiles among the basidiospore isolates of mutant strain were identical, indicating that the mutant strain produced isogenic basidiospore progeny.