A molecular phylogenetic reappraisal of the Didymosphaeriaceae(=Montagnulaceae)

The ascomycetous families,Didymosphaeriaceae and Montagnulaceae,have been treated in Pleosporales,Dothideomycetes,and both include saprobes,endophytes and pathogens associated with a wide variety of substrates worldwide.Didymosphaeriaceae was characterized by 1-septate ascospores and trabeculate pseudoparaphyses,mainly anastomosing above the asci,while species in Montagnulaceae had 1 to multi-septate ascospores and generally cellular pseudoparaphyses.In recent treatments,Bimuria,Didymocrea,Kalmusia,Karstenula,Montagnula,Paraphaeosphaeria,Paraconiothyrium and Letendraea were placed in Montagnulaceae,while only Didymosphaeria has been placed in Didymosphaeriaceae.New morphological and molecular data from recent collections have become available and thus the understanding of the families can be improved.Based on analyses of concatenated internal transcribed spacer(ITS)with LSU,SSU andβ-tubulin gene sequences,the taxonomy of the genera classified in these families are reassessed.Our phylogenetic analyses conclude that,the recently introduced Didymosphaeria rubi-ulmifolii with Paraconiothyrium brasi liense species complex,Alloconiothyrium,Bimuria,Deniquelata,Didymocrea,Kalmusia,Karstenula,Letendraea,Montagnula,Neokalmusia,Paraconiothyrium,Paraphaeosphaeria,Phaeodothis and Tremateia,forms a robust clade named here Didymosphaeriaceae.We therefore synonymize Montagnulaceae under Didymosphaeriaceae which is the oldest name and has priority and provide a update account of the family.Didymosphaeria is represented by Didymosphaeria rubi-ulmifolii.A new genus,Neokalmusia,is introduced in the family to accommodate the bambusi colous taxa Kalmusia brevispora and K.scabrispora.This introduction is based on molecular data coupled with morphology.One new species,Paraconiothyrium magnoliae and the sexual morph of Paraconiothyrium fuckelii,is also introduced.Julella and Barria are assigned to the family based on morphological similarity with Didymosphaeriaceae.Wilmia(previously referred to the Phaeosphaeriaceae)is synonymized under Letendraea(Didymosphaeriaceae).Furthermore,a new species,Letendraea cordylinicola,is introduced and placed in Didymosphaeriaceae based on phylogeny and morphology.The paraphyletic nature of Paraconiothyrium is partially resolved,but further sampling with fresh collections and molecular data of species in this genus are needed to obtain a natural classification.

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 analys is 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.