Dong-Qin Dai

Phyllosticta—an overview of current status of species recognition

Phyllosticta is an important coelomycetous plant pathogenic genus known to cause leaf spots and various fruit diseases worldwide on a large range of hosts. Species recognition in Phyllosticta has historically been based on morphology, culture characters and host association. Although there have been several taxonomic revisions and enumerations of species, there is still considerable confusion when identifying taxa. Recent studies based on molecular data have resolved some cryptic species and some novel taxa have been discovered. However, compared to the wide species diversity and taxonomic records, there is a lack of molecular studies to resolve current names in the genus. A phylogenetic tree is here generated by combined gene analysis (ITS, partial actin and partial elongation factor 1α) using a selected set of taxa including type-derived sequences available in GenBank. Life modes, modal lifecycle and applications of the genus in biocontrol and metabolite production are also discussed. We present a selected set of taxa as an example of resolved and newly described species in the genus and these are annotated with host range, distribution, disease symptoms and notes of additional information with comments where future work is needed.

Revision of Phaeosphaeriaceae

Phaeosphaeriaceae is a large and important family in the order Pleosporales which includes economically important plant pathogens. Species may also be endophytes or saprobes on plant hosts, especially on monocotyledons (e.g., Cannaceae, Cyperaceae, Juncaceae, Poaceae); some species have also been reported on dicotyledons. The family previously accommodated 35 sexual and asexual genera and comprised more than 300 species with a range of morphological characters. The morphological characters of taxa in this family are often ambiguous and can be confused with other taxa in Leptosphaeriaceae and Montagnulaceae. Fourteen specimens of the type genera of Phaeosphaeriaceae were loaned from herbaria worldwide and were re-examined and illustrated. Fresh collections were obtained from Italy and Thailand, characterized, examined, isolated into pure culture and used to obtain molecular data. The asexual state was induced where possible on sterile bamboo pieces placed on water agar. Multigene phylogenetic analyses of ITS, LSU, SSU, RPB2 and TEF1 sequence datasets were carried out using maximum likelihood, maximum parsimony and Bayesian analysis. Molecular analyses shows that 21 genera (Amarenomyces, Ampelomyces, Chaetosphaeronema, Dematiopleospora, Entodesmium, Loratospora, Neosetophoma, Neostagonospora, Nodulosphaeria, Ophiobolus, Ophiosphaerella, Paraphoma, Parastagonospora, Phaeosphaeria, Phaeosphaeriopsis, Sclerostagonospora, Setomelanomma, Setophoma, Vrystaatia, Wojnowicia and Xenoseptoria) belong in Phaeosphaeriaceae, while seven genera (Amarenographium, Bricookea, Dothideopsella, Eudarluca, Phaeostagonospora, Scolecosporiella and Tiarospora) are included based on morphological data. Amarenomyces is reinstated and Nodulosphaeria is confirmed in Phaeosphaeriaceae. Eudarluca is distinguished from Sphaerellopsis based on its morphological characters and is typical of Phaeosphaeriaceae. ITS gene phylogenetic analysis indicates that Sphaerellopsis belongs to Leptosphaeriaceae. Ophiobolus species form a clade within Phaeosphaeriaceae while Ophiosphaerella is shown to be polyphyletic. Phaeosphaeria sensu stricto is redefined. Two new species of Phaeosphaeria and one of Phaeosphaeriopsis are introduced while the asexual states of Phaeosphaeria chiangraina and Phaeosphaeriopsis dracaenicola are reported. Scolicosporium minkeviciusii forms a sister clade with Neostagonospora and Parastagonospora in Phaeosphaeriaceae. However, Scolicosporium minkeviciusii is not the type species. Thus, the placement of Scolicosporium sensu stricto in Phaeosphaeriaceae is questionable. Phylogenetic analysis of combined ITS and LSU genes, confirm the placement of Septoriella oudemansii in Phaeosphaeriaceae. However, it is not represented by the generic type, thus the placement of Septoriella is questionable. Setophaeosphaeria is excluded from Phaeosphariaceae as the type species, Sp. hemerocallidis forms a clade at the base of Cucurbitariaceae. Wilmia clusters in Didymosphaeriaceae and is synonymized under Letendraea. Barria, Chaetoplea, Hadrospora, Lautitia, Metameris, Mixtura and Pleoseptum are excluded from Phaeosphaeriaceae based on their morphological characters. The asexual genera Mycopappus and Xenostigmina are excluded from this family based on the phylogenetic evidence; these genera form a clade close to Melanommataceae.

Bambusicola, a New Genus from Bamboo with Asexual and Sexual Morphs

Abstract Bambusicola, gen. nov., is introduced for four new saprobic taxa from culms of bamboos in northern Thailand. One species, chosen as the generic type, has both sexual and asexual morphs, one species has the sexual morph only and two species have the asexual morph only. The four new species, Bambusicola massarinia, B. bambusae, B. irregulispora and B. splendida are illustrated and described. Isolates of each species were sequenced using LSU, SSU and ITS genes and phylogenetic analysis shows the genus to be a distinct clade in the suborder “Massarineae”. Morphological differences between Bambusicola and some related genera are noted. Bambusicola is characterized by small, cone-shaped ascomata, slightly broad and fusiform ascospores and a coelomycete asexual morph with light brown conidia. Bambusicola clusters in Trematosphaeriaceae, but the closeness of this relationship cannot be resolved.

Towards a natural classification of Astrosphaeriella-like species; introducing Astrosphaeriellaceae and Pseudoastrosphaeriellaceae fam. nov and Astrosphaeriellopsis, gen. nov.

Astrosphaeriella sensu lato is a common genus occurring on bamboo, palms and stout grasses. Species of Astrosphaeriella have been collected from various countries in tropical, subtropical or temperate regions. In Asia, species have been collected in Brunei, China, Indonesia, Japan, Philippines and Vietnam. There have been several morphological studies on Astrosphaeriella, but molecular work and phylogenetic analyses are generally lacking. Taxa included in Astrosphaeriella were characterized in three main groups 1) typical Astrosphaeriella species (sensu stricto) having carbonaceous, erumpent, conical ascostromata 2) atypical Astrosphaeriella species (sensu lato) having immersed, coriaceous ascostromata with short to long papilla and 3) lophiostoma-like species having immersed ascostromata with slit-like openings. Some of the latter Astrosphaeriella species, having slit-like openings, have been transferred to Fissuroma and Rimora in Aigialaceae. In this study five type specimens of Astrosphaeriella were loaned from herbaria worldwide and re-examined and are re-described and illustrated. Collections of Astrosphaeriella were also made in Thailand and morphologically examined. Pure cultures were obtained from single spores and used in molecular studies. The asexual morph was induced on sterile bamboo pieces placed on water agar. Phylogenetic analyses of combined LSU, SSU and TEF1 sequence data of astrosphaeriella-like species using Bayesian, Maximum parsimony (MP) and Randomized Accelerated Maximum Likelihood (RAxML) analyses were carried out. Phylogenetic analyses show that species of Astrosphaeriella can be distinguished in at least three families. Species of Astrosphaeriellasensu stricto with erumpent, carbonaceous ascostromata, form a strongly supported clade with Pteridiospora species and a new family, Astrosphaeriellaceae, is introduced to accommodate these taxa. The genera are revised and Astrosphaeriella bambusae, A. neofusispora, A. neostellata, A. thailandica, A. thysanolaenae and Pteridiospora chiangraiensis are introduced as new species. Astrosphaeriella exorrhiza is reported on a dead stem of Thysanolaena maxima and is the first record for Thailand. Reference specimens for A. fusispora and A. tornata are designated to stabilize the taxonomy of Astrosphaeriella. The coelomycetous asexual morph of A. bambusae is reported and forms hyaline, globose to subglobose, aseptate conidia. Species of Astrosphaeriellasensu lato with immersed, coriaceous ascostromata, with short to long papilla and striate ascospores, form a sister clade with Tetraplosphaeriaceae. The genus Pseudoastrosphaeriella is introduced to accommodate some of these taxa with three new species and three new combinations, viz. P. aequatoriensis, P. africana, P. bambusae, P. longicolla, P. papillata and P. thailandensis. A new family Pseudoastrosphaeriellaceae is introduced to accommodate this presently monotypic lineage comprising Pseudoastrosphaeriella. The asexual morph of P. thailandensis is described. Astrosphaeriella bakeriana forms a distinct clade basal to Aigialaceae. Astrosphaeriella bakeriana is excluded from Astrosphaeriella and a new genus Astrosphaeriellopsis, placed in Dothideomycetes genera incertae sedis, is introduced to accommodate this taxon. Fissuroma aggregata (Aigialaceae) is re-visited and is shown to be a cryptic species. Three new species of Fissuroma and a new combination are introduced based on morphology and phylogeny viz. F. bambusae, F. fissuristoma, F. neoaggregata and F. thailandicum. The asexual morph of Fissuroma bambusae is also reported.

Pustulomyces gen. nov. Accommodated in Diaporthaceae, Diaporthales, as Revealed by Morphology and Molecular Analyses

Abstract A new coelomycetous genus, Pustulomyces, inhabiting decaying bamboo, is introduced based on morpho-molecular studies. Pustulomyces is characterized by immersed, pustule-like, acervular conidiomata, with dark ostiolar necks, enteroblastic, phialidic conidiogenous cells with a small collarette and fusiform, sigmoid, aseptate, guttulate conidia. In morphology it is similar with Bambusicola (Bambusicolaceae), but maximum-likelihood and Bayesian analyses of the combined LSU and TEF-1 alpha sequence data set shows Pustulomyces belongs in Diaporthaceae, Diaporthales. The new fungus is compared with other morphologically and phylogenetically similar genera.

Valsaria and the Valsariales

More than 100 recent collections of Valsaria sensu lato mostly from Europe were used to elucidate the species composition within the genus. Multigene phylogeny based on SSU, LSU, ITS, rpb2 and tef1 sequences revealed a monophyletic group of ten species within the Dothideomycetes, belonging to three morphologically similar genera. This group could not be accommodated in any known family and are thus classified in the new family Valsariaceae and the new order Valsariales. The genus Valsaria sensu stricto comprises V. insitiva, V. robiniae, V. rudis, V. spartii, V. lopadostomoides sp. nov. and V. neotropica sp. nov., which are phylogenetically well-defined, but morphologically nearly indistinguishable species. The new monotypic genus Bambusaria is introduced to accommodate Valsaria bambusae. Munkovalsaria rubra and Valsaria fulvopruinata are combined in Myrmaecium, a genus traditionally treated as a synonym of Valsaria, which comprises three species, with M. rubricosum as its generic type. This work is presented as a basis for additional species to be detected in future.

Vamsapriya (Xylariaceae) re-described, with two new species and molecular sequence data

Abstract Vamsapriya comprises two species from bamboo and is characterized by erect, rigid, dark brown, synnematous conidiophores, monotretic conidiogenous cells and brown to dark brown, septate, conidia in chains. Vamsapriya indica, the generic type of Vamsapriya, was recollected and isolated from bamboo culms in Chiang Rai Province, Thailand and is described, illustrated and epitypified in this paper. Two new species in the genus were also discovered and are introduced as V. khunkonensis and V. bambusicola. The new species differs from the type and the other known species, V. mahabaleshwarensis, in the shape and size of the conidia. Maximum-parsimony (MP) analysis of combined LSU, SSU and RPB2 sequence data and Bayesian analysis based on multi-gene data set of betatubulin, ITS, LSU, and RPB2 show Vamsapriya belongs in Xylariaceae, Xylariales.

Multi-Gene Analyses Reveal Taxonomic Placement of Scolicosporium minkeviciusii in Phaeosphaeriaceae (Pleosporales)

Abstract Scolicosporium minkeviciusii, was newly collected in Italy, and subjected to morpho-molecular analyses. Morphological characters clearly indicate that this species is a coelomycete. Combined maximum-likelihood and maximum-parsimony analyses of LSU and SSU gene sequence data of S. minkeviciusii grouped it in Phaeosphaeriaceae with Phaeosphaeria nodorum, P. oryzcie and Stagonospora foliicola, although the type species of Scolicosporium, S. macrosporium, which has not been sequenced, is considered to belong in the family Pleomassariaceae. In this study, we designate an epitype for Scolicosporium minkeviciusii. The placement of S. macrosporium and Scolicosporium sensu stricto remains uncertain and further morpho-molecular studies are necessary to confirm the taxonomic placement of this type species and to delimit this genus.

Poaceascoma helicoides gen et sp. nov., a New Genus with Scolecospores in Lentitheciaceae

Abstract An ophiosphaerella-like species was collected from dead stems of a grass (Poaceae) in Northern Thailand. Combined analysis of LSU, SSU and RPB2 gene data, showed that the species clusters with Lentithecium arundinaceum, Setoseptoria phragmitis and Stagonospora macropycnidia in the family Lentitheciaceae and is close to Katumotoa bambusicola and Ophiosphaerella sasicola. Therefore, a monotypic genus, Poaceascoma is introduced to accommodate the scolecosporous species Poaceascoma helicoides. The species has similar morphological characters to the genera Acanthophiobolus, Leptospora and Ophiosphaerella and these genera are compared.

Four new species of Tubeufia (Tubeufiaceae, Tubeufiales) from Thailand

Tubeufia was named for a sexual morph taxon. However, several asexual morph species have been accommodated in this genus as well. In our study, four new species of Tubeufia, viz. T. filiformis, T. latispora, T. laxispora and T. mackenziei, are described and illustrated. The phylogenetic placement of the new species is confirmed by analysis of combined ITS, LSU and TEF1α sequence data. A key to Tubeufia species is provided and the new species are compared with similar fungal taxa.