The genus Thelonectria and closely related species with cylindrocarpon-like asexual states are a group of perithecial ascomycetes in the family Nectriaceae that occur as saprobes and in few cases as pathogens of hardw...The genus Thelonectria and closely related species with cylindrocarpon-like asexual states are a group of perithecial ascomycetes in the family Nectriaceae that occur as saprobes and in few cases as pathogens of hardwood trees,shrubs or other plants.Although a key component of forest ecosystems around the world,species relationships and distributions of these fungi are largely unknown.The objectives of this study were to:1)infer species rank phylogenetic relationships of the genus Thelonectria and closely related species with cylindrocarpon-like asexual states and test the monophyly of each of the groups studied;2)delimit taxa establishing taxon circumscriptions;3)resolve nomenclatural issues by identifying redundantly used names and synonyms;and 4)provide an updated outline to the genus,geographical distributions data and identification tools,specifically diagnostic keys and molecular data that can be used as molecular barcodes.The recovered consensus phylogeny resulted in a narrow circumscription of the genus Thelonectria,based on the type T.discophora,excluding one of the common species T.jungneri.According to the phylogenetic analyses,T.jungneri belongs in a segregate clade that should be recognized as a different genus.In the genus Thelonectria,a total of four new species and three new combinations are recognized.Additionally,three new genera,closely related to Thelonectria,are described to accommodate species displaying a morphological resemblance to those of Thelonectria:Cinnamomeonectria gen.nov.with C.cinnamomea as type species,Macronectria gen.nov.with M.jungneri as type species and including four additional newly described species,and Tumenectria gen.nov.with T.laetidisca as type species.展开更多
Specimens regarded as Thelonectria discophora(Thelonectria,Nectriaceae,Hypocreales)constitute a conspicuous group of saprobic fungi on decaying plant material,characterized by red perithecia each with a broad mammifor...Specimens regarded as Thelonectria discophora(Thelonectria,Nectriaceae,Hypocreales)constitute a conspicuous group of saprobic fungi on decaying plant material,characterized by red perithecia each with a broad mammiform(nipple-like)apex.The asexual state is characterized by a cylindrocarpon-like morphology,with 3–5 septate macroconidia,unicellular microconidia and chlamydospores that are rarely produced in culture.In the past,T.discophora was regarded as one species with a wide geographic distribution.However,a recent study rejected the monophyly and cosmopolitan distribution of this species,and showed the existence of at least 16 cryptic species distributed in three main groups.By combining the results of phylogenetic analyses of six nuclear loci and morphological studies,we revised the taxonomy of the T.discophora species complex,resulting in the description of 12 new species and four new combinations based on historic names.Even though molecular phylogenetic analyses strongly support the segregation of these species,and are in agreement with previous studies,individual diagnostic morphological characters for each species could not be identified.However,discrete morphological traits corresponding to each of the three main groups of species were discovered.Lineages could be differentiated based on the average values of morphological traits as well as the presence/absence of characteristic asexual propagules and colony growth at 30C.Descriptions,illustrations are provided for the recognized species.展开更多
基金This study was funded by a grant from United States National Science Foundation(PEET program)DEB-0925696。
文摘The genus Thelonectria and closely related species with cylindrocarpon-like asexual states are a group of perithecial ascomycetes in the family Nectriaceae that occur as saprobes and in few cases as pathogens of hardwood trees,shrubs or other plants.Although a key component of forest ecosystems around the world,species relationships and distributions of these fungi are largely unknown.The objectives of this study were to:1)infer species rank phylogenetic relationships of the genus Thelonectria and closely related species with cylindrocarpon-like asexual states and test the monophyly of each of the groups studied;2)delimit taxa establishing taxon circumscriptions;3)resolve nomenclatural issues by identifying redundantly used names and synonyms;and 4)provide an updated outline to the genus,geographical distributions data and identification tools,specifically diagnostic keys and molecular data that can be used as molecular barcodes.The recovered consensus phylogeny resulted in a narrow circumscription of the genus Thelonectria,based on the type T.discophora,excluding one of the common species T.jungneri.According to the phylogenetic analyses,T.jungneri belongs in a segregate clade that should be recognized as a different genus.In the genus Thelonectria,a total of four new species and three new combinations are recognized.Additionally,three new genera,closely related to Thelonectria,are described to accommodate species displaying a morphological resemblance to those of Thelonectria:Cinnamomeonectria gen.nov.with C.cinnamomea as type species,Macronectria gen.nov.with M.jungneri as type species and including four additional newly described species,and Tumenectria gen.nov.with T.laetidisca as type species.
基金This study was supported in part by the United States National Science Foundation (NSF) PEET grant DEB-0731510‘Monographic Studies in the Nectriaceae,Hypocreales:Nectria,Cosmospora,and Neonectria' to University of Maryland
基金funded by a grant from United States National Science Foundation(PEET program)DEB-0925696:“Monographic Studies in the Nectriaceae,Hypocreales:Nectria,Cosmospora,and Neonectria”to University of Maryland(P.Chaverri,G.J.Samuels&A.Y.Rossman).
文摘Specimens regarded as Thelonectria discophora(Thelonectria,Nectriaceae,Hypocreales)constitute a conspicuous group of saprobic fungi on decaying plant material,characterized by red perithecia each with a broad mammiform(nipple-like)apex.The asexual state is characterized by a cylindrocarpon-like morphology,with 3–5 septate macroconidia,unicellular microconidia and chlamydospores that are rarely produced in culture.In the past,T.discophora was regarded as one species with a wide geographic distribution.However,a recent study rejected the monophyly and cosmopolitan distribution of this species,and showed the existence of at least 16 cryptic species distributed in three main groups.By combining the results of phylogenetic analyses of six nuclear loci and morphological studies,we revised the taxonomy of the T.discophora species complex,resulting in the description of 12 new species and four new combinations based on historic names.Even though molecular phylogenetic analyses strongly support the segregation of these species,and are in agreement with previous studies,individual diagnostic morphological characters for each species could not be identified.However,discrete morphological traits corresponding to each of the three main groups of species were discovered.Lineages could be differentiated based on the average values of morphological traits as well as the presence/absence of characteristic asexual propagules and colony growth at 30C.Descriptions,illustrations are provided for the recognized species.
