Emendation of Kiliophora (Xylariales incertae sedis), a new species and a new combination

Kiliophora is a hyphomycete genus whose species are involved in leaf litter decomposition. It was originally described with polytretic conidiogenesis. Based on observation of fresh specimens collected in Brazil and bibliographic revision, an emended description is proposed in order to rectify the mode of conidial production. The presence of minute polar extensions at both ends of conidia is stated as a diagnostic generic character. A new species, Kiliophora clavatophora, and a new combination, Kiliophora aseptata, are proposed. The new species is characterized by its conidiophores with clavate apical cell, its ellipsoidal conidiogenous cell and fusiform conidia. A table for comparison of all accepted species is also included.

A morpho-molecular re-appraisal of Polystigma fulvum and P. rubrum (Polystigma, Polystigmataceae)

Collections of eleven Prunus specimens infected with Polystigma species from Belarus and Russia yielded two existing taxa: Polystigma fulvum (sexual morph) and Polystigma rubrum (asexual morph). DNA based phylogenies of large subunit nuclear rDNA (LSU) and nuclear ribosomal internal transcribed spacer (ITS) are provided for the first time for Polystigma fulvum and its placement is confirmed within Polystigmataceae. The concatenated LSU and ITS DNA sequence data for P. rubrum, analyzed to infer its potential relationship to other Polystigma species, also show that strains of P. rubrum are segregated into two subclades with sufficient genetic differences. No significant differences in morphology or morphometry among the strains of P. rubrum between the two subclades, especially vis-à-vis the conidiogenous cell and conidium sizes are observed (P>0.05). Subspecies concept of P. rubrum complex is discussed.

Introducing Dictyochaeta aquatica sp. nov. and two new species of Chloridium (Chaetosphaeriaceae, Sordariomycetes) from aquatic habitats

During our ongoing investigations of freshwater fungi in Thailand, three new chaetosphaeriaceous species, Chloridium aquaticum, Chloridium aseptatum and Dictyochaeta aquatica, were found on submerged wood in freshwater habitats. To determine their placement, a phylogenetic analysis of combined LSU and ITS sequence data was performed. Chloridium aquaticum is the only species having proliferating conidiophores and holoblastic conidiogenous cell in Chloridium. A detailed description and illustrations of the taxa is provided and phylogenetic relationship between the new taxa and their relatives are compared and discussed.

Autophagy-associated alpha-arrestin signaling is required for conidiogenous cell development in Magnaporthe oryzae

Conidiation patterning is evolutionarily complex and mechanism concerning conidiogenous cell differentiation remains largely unknown. Magnaporthe oryzae conidiates in a sympodial way and uses its conidia to infect host and disseminate blast disease. Arrestins are multifunctional proteins that modulate receptor down-regulation and scaffold components of intracellular trafficking routes. We here report an alpha-arrestin that regulates patterns of conidiation and contributes to pathogenicity in M. oryzae. We show that disruption of ARRDC1 generates mutants which produce conidia in an acropetal array and ARRDC1 significantly affects expression profile of CCA1, a virulence-related transcription factor required for conidiogenous cell differentiation. Although germ tubes normally develop appressoria, penetration peg formation is dramatically impaired and Δarrdc1 mutants are mostly nonpathogenic. Fluorescent analysis indicates that EGFP-ARRDC1 puncta are well colocalized with DsRed2-Atg8, and this distribution profile could not be altered in Δatg9 mutants, suggesting ARRDC1 enters into autophagic flux before autophagosome maturation. We propose that M. oryzae employs ARRDC1 to regulate specific receptors in response to conidiation-related signals for conidiogenous cell differentiation and utilize autophagosomes for desensitization of conidiogenous receptor, which transmits extracellular signal to the downstream elements of transcription factors. Our investigation extends novel significance of autophagy-associated alpha-arrestin signaling to fungal parasites.

Pleomorphic conidiogenesis among strains of Knufia cryptophialidica

Pleomorphic conidiogenesis was examined in four strains of Knufia cryptophialidica Hutchison & Untereiner in culture. The ex-type strain (DAOM 216555) was the most plastic, exhibiting various patterns of conidiogenesis, and was the only strain that produced phialides, that is, the most important diagnostic structure of the genus, although many of these phialides were aberrant and produced abnormally swollen conidia that appeared to lack cytoplasm. Subsequently, hyphae emerged from the aberrant phialides and some of these hyphae later disarticulated to form thallic-arthric conidia. The ex-type strain ceased to produce normal phialides after several serial transfers onto malt extract agar. Endoconidiogenesis in K. cryptophialidica, reported here for the first time, involved subdivision of conidiogenous cells by septation and schizolysis through the septa, and their release was by rupture and subsequent degeneration of the conidiogenous cell wall. Both thallic-arthric and endogenous conidia occurred in all strains and may serve as more reliable diagnostic characters of K. cryptophialidica than phialidic conidia.Key words: black meristematic fungus, endoconidia, phialides.

Ultrastructure of conidiogenesis and appendage ontogeny in the coelomycete Bartalinia robillardoides

Conidiogenesis and conidial appendage ontogeny of the coelomycete Bartalinia robillardoides Tassi was studied at the light microscope, scanning electron microscope, and transmission electron microscope levels. Conidiogenesis in B. robillardoides is holoblastic. Appendage ontogeny begins as a cellular outgrowth of the apical and the basal cells of the young conidium, the former developing prior to the basal appendage. Conidia detach from the conidiogenous cells schizolytically. Mature conidial cell walls comprise two layers: an outer electron-dense layer, 30–38 nm, and an inner less electron-dense layer, 100–125 nm. The apical appendages arise from an outgrowth of the apical cell, which then branches to form the appendages. The single basal appendage arises from the junction between the basal cell of the conidium and the conidiogenous cell prior to conidial detachment from the conidiogenous cell, as an outgrowth of the conidial cell wall. Conidial appendage ontogeny is compared with those of other coelomycetes.Key words: Annellidic, appendage ontogeny, coelomycetes, holoblastic.

Ceratocystis moniliformopsis sp. nov., an early coloniser of Eucalyptus obliqua logs in Tasmania, Australia

A new species of Ceratocystis with a Chalara anamorph was observed to cause black stains on the cut surfaces of recently felled Eucalyptus obliqua logs in south-western Tasmania, Australia. It is described as C. moniliformopsis because of its similarity to C. moniliformis in morphology of ascospores and perithecia. This is a homothallic species and is characterised by a thick perithecial peridium, ovoid perithecia and disciform-based perithecial necks with convergent ostiolar hyphae. The perithecia are covered with the following two types of ornamenting hyphae: hyaline, thin-walled, aseptate, tubular hairs and dark brown, thick-walled, ampliform to conical setae. Its Chalara anamorph has the following two types of conidiogenous cells: hyaline, cylindrical tapering phialides and pigmented, cupulate or divergent phialides with percurrent proliferation. The latter is a unique type of conidiogenous cell that has not been observed in this genus before the present study.

"Helminthosporium" asterinum, Polydesmus elegans, Imimyces, and allies

Helminthosporium asterinum Cooke (=Helminthosporium papulosum Anth. Berg, Helminthosporium phomatae Dearn. & House) is redescribed and transferred to Ellisembia because of distinctions in the kind of conidiogenous cell. Polydesmus elegans Durieu & Mont. is redescribed and Helminthosporium densum Sacc. & Roum. and Taeniolella bilgramii S.S. Reddy & S.M. Reddy are its synonyms. Imimyces A. Hern.-Guit. & B. Sutton, typified by H. densum Sacc. & Roum., is a synonym of Polydesmus Mont. Consequent to the exclusion of the type species of Imimyces, a new genus, Imicles, typified by Helminthosporium leptosporum Sacc. & Roum., is proposed for the residue of species formerly included in Imimyces.Key words: apple, pear, black-pox, Corynespora, Corynesporina, Sporidesmium.