Investigating species boundaries in Colletotrichum

Colletotrichum is one of the most important plant pathogenic genera that is responsible for numerous diseases which can have a profound impact on the agricultural sector.Species delineation is difficult due to a lack of distinctive phenotypic vari-ation.Therefore,in this study three different genomic approaches based on phylogenetic,evolutionary and coalescent-based methods are applied to establish robust species boundaries.The reliability of five different DNA barcodes was also assessed to provide further insights into species delineation.The ITS region can resolve the placement of taxa up to the species complex level.The GAPDH and TUB2 markers are determined to be the most informative for most complexes.However,no single marker could discriminate between species in all complexes,therefore different molecular approaches based on multi-locus datasets are recommended.This is the first study to provide an estimated divergence time for all species complexes in Colle-totrichum.The estimated divergence time for species complexes ranged between 4.8 to 32.2 MYA.Based on the high level of congruent results obtained from the different molecular approaches,a new species complex,the Colletotrichum agaves complex is introduced.This complex consists of five taxa which are characterised by the presence of straight or slightly curved conidia with obtuse apices.This study shows that coalescent approaches and multi-locus phylogeny are crucial to establish species boundaries in Colletotrichum.The taxonomic placement of three singleton taxa Colletotrichum axonopodi,C.cariniferi and C.parallelophorum is revised.We accept 248 species and provide recommendations regarding species boundaries in the graminicola-caudatum complex.

The numbers of fungi: is the descriptive curve flattening?

The recent realistic estimate of fungal numbers which used various algorithms was between 2.2 and 3.8 million.There are nearly 100,000 accepted species of Fungi and fungus-like taxa,which is between 2.6 and 4.5%of the estimated species.Several forums such as Botanica Marina series,Fungal Diversity notes,Fungal Biodiversity Profiles,Fungal Systematics and Evolution-New and Interesting Fungi,Mycosphere notes and Fungal Planet have enhanced the introduction of new taxa and nearly 2000 species have been introduced in these publications in the last decade.The need to define a fungal species more accurately has been recognized,but there is much research needed before this can be better clarified.We address the evidence that is needed to estimate the numbers of fungi and address the various advances that have been made towards its understanding.Some genera are barely known,whereas some plant pathogens comprise numerous species complexes and numbers are steadily increasing.In this paper,we examine ten genera as case studies to establish trends in fungal description and introduce new species in each genus.The genera are the ascomycetes Colletotrichum and Pestalotiopsis(with many species or complexes),Atrocalyx,Dothiora,Lignosphaeria,Okeanomyces,Rhamphoriopsis,Thozetella,Thyrostroma(rela-tively poorly studied genera)and the basidiomycete genus Lepiota.We provide examples where knowledge is incomplete or lacking and suggest areas needing further research.These include(1)the need to establish what is a species,(2)the need to establish how host-specific fungi are,not in highly disturbed urban areas,but in pristine or relatively undisturbed forests,and(3)the need to establish if species in different continents,islands,countries or regions are different,or if the same fungi occur worldwide?Finally,we conclude whether we are anywhere near to flattening the curve in new species description.

What are fungal species and how to delineate them?

This is the opening paper in the special issue of Fungal Diversity,which collates the data on defining species.Defining and recognizing species has long been a controversial issue.Since Darwin’s proposed origin of species,over 30 species criteria have been brought forth and used to define species boundaries.In recent times,phylogenetic analyses based on multiple loci have been extensively used as a method to define species boundaries.However,only a few mycologists are aware that phylogenetic species criteria can mask discordances among fungal groups,leading to inaccurately defined species bounda-ries.In the current review,we discuss species recognition criteria,how and where these criteria can be applied along with their limitations and derived alternatives.In order to delimit fungal species,authors need to take into account not only the phylogenetic and phenotypic coherence,but also the timing of events that lead to fungal speciation and subsequent diversi-fications.Variations in the rate of phenotypic diversifications and convergent fungal evolution make it difficult to establish a universal species recognition criterion.The best practice can only be defined in the context of each fungal group.In this review,we provide a set of guidelines,encouraging an integrative taxonomic approach for species delimitation that can be used to define fungal species boundaries in the future.The other papers in this special issue deal with fungal speciation in Ascomycota,Dothideomycetes,Basidiomycota,basal fungi,lichen-forming fungi,plant pathogenic fungi,and yeasts.

A polyphasic approach to delineate species in Bipolaris

Bipolaris species are important plant pathogens with a worldwide distribution in tropical and temperate environments.Species recognition in Bipolaris has been problematic due to a lack of molecular data from ex-type cultures,the use of few gene regions for species resolution and overlapping morphological characters.In this study,we evaluate the efficiency of different DNA barcodes in species delimitation in Bipolaris by phylogenetic analyses,Automatic Barcode Gap Discovery and Objective Clustering.GAPDH is determined to be the best single marker for the genus.These approaches are used to clarify the taxonomic placement of all sequences currently named as Bipolaris in GenBank based on ITS and GAPDH gene sequence data.In checking various publications,we found that the majority of new host records of fungal species published in the Plant Disease journal from 2010 to 2019 were based on BLAST searches of the ITS sequences and up to 82%of those records could be erroneous.Therefore,relying on BLAST searches from GenBank to name species is not recommended.Editorial boards of journals and reviewers of new record papers should be aware of this problem.In naming Bipolaris species,whether new or known,it is recommended to perform phylogenetic analyses based on GAPDH using the correct taxon sampling for accurate results and the species relationship should have reliable statistical support.At least two new species are represented by molecular data in GenBank and we provide an updated taxonomic revision of Bipolaris.We accept 45 species in Bipolaris and notes are provided for all the species including hosts and geographic distribution.

One stop shop IV: taxonomic update with molecular phylogeny for important phytopathogenic genera: 76-100 (2020)

This is a continuation of a series focused on providing a stable platform for the taxonomy of phytopathogenic fungi and fungus-like organisms.This paper focuses on one family:Erysiphaceae and 24 phytopathogenic genera:Armillaria,Barrio-psis,Cercospora,Cladosporium,Clinoconidium,Colletotrichum,Cylindrocladiella,Dothidotthia,,Fomitopsis,Ganoderma,Golovinomyces,Heterobasidium,Meliola,Mucor,Neoerysiphe,Nothophoma,Phellinus,Phytophthora,Pseudoseptoria,Pythium,Rhizopus,Stemphylium,Thyrostroma and Wojnowiciella.Each genus is provided with a taxonomic background,distribution,hosts,disease symptoms,and updated backbone trees.Species confirmed with pathogenicity studies are denoted when data are available.Six of the genera are updated from previous entries as many new species have been described.

Refined families of Dothideomycetes:orders and families incertae sedis in Dothideomycetes

Numerous new taxa and classifications of Dothideomycetes have been published following the last monograph of families of Dothideomycetes in 2013.A recent publication by Honsanan et al.in 2020 expanded information of families in Dothideo-mycetidae and Pleosporomycetidae with modern classifications.In this paper,we provide a refined updated document on orders and families incertae sedis of Dothideomycetes.Each family is provided with an updated description,notes,including figures to represent the morphology,a list of accepted genera,and economic and ecological significances.We also provide phylogenetic trees for each order.In this study,31 orders which consist 50 families are assigned as orders incertae sedis in Dothideomycetes,and 41 families are treated as families incertae sedis due to lack of molecular or morphological evidence.The new order,Catinellales,and four new families,Catinellaceae,Morenoinaceae Neobuelliellaceae and Thyrinulaceae are introduced.Seven genera(Neobuelliella,Pseudomicrothyrium,Flagellostrigula,Swinscowia,Macroconstrictolumina,Pseudobogoriella,and Schummia)are introduced.Seven new species(Acrospermum urticae,Bogoriella complexoluminata,Dothiorella ostryae,Dyfrolomyces distoseptatus,Macroconstrictolumina megalateralis,Patellaria microspora,and Pseu-domicrothyrium thailandicum)are introduced base on morphology and phylogeny,together with two new records/reports and five new collections from different families.Ninety new combinations are also provided in this paper.

Microfungi associated with Clematis(Ranunculaceae)with an integrated approach to delimiting species boundaries

The cosmopolitan plant genus Clematis contains many climbing species that can be found worldwide.The genus occurs in the wild and is grown commercially for horticulture.Microfungi on Clematis were collected from Belgium,China,Italy,Thailand and the UK.They are characterized by morphology and analyses of gene sequence data using an integrated species concept to validate identifications.The study revealed two new families,12 new genera,50 new species,26 new host records with one dimorphic character report,and ten species are transferred to other genera.The new families revealed by multigene phylogeny are Longiostiolaceae and Pseudomassarinaceae in Pleosporales(Dothideomycetes).New genera are Anthodidymella(Didymellaceae),Anthosulcatispora and Parasulcatispora(Sulcatisporaceae),Fusiformispora(Amniculicolaceae),Longispora(Phaeosphaeriaceae),Neobyssosphaeria(Melanommataceae),Neoleptosporella(Chaetosphaeriales,genera incertae sedis),Neostictis(Stictidaceae),Pseudohelminthosporium(Neomassarinaceae),Pseudomassarina(Pseudomassarinaceae),Sclerenchymomyces(Leptosphaeriaceae)and Xenoplectosphaerella(Plectosphaerellaceae).The newly described species are Alloleptosphaeria clematidis,Anthodidymella ranunculacearum,Anthosulcatispora subglobosa,Aquadictyospora clematidis,Brunneofusispora clematidis,Chaetosphaeronema clematidicola,C.clematidis,Chromolaenicola clematidis,Diaporthe clematidina,Dictyocheirospora clematidis,Distoseptispora clematidis,Floricola clematidis,Fusiformispora clematidis,Hermatomyces clematidis,Leptospora clematidis,Longispora clematidis,Massariosphaeria clematidis,Melomastia clematidis,M.fulvicomae,Neobyssosphaeria clematidis,Neoleptosporella clematidis,Neoroussoella clematidis,N.fulvicomae,Neostictis nigricans,Neovaginatispora clematidis,Parasulcatispora clematidis,Parathyridaria clematidis,P.serratifoliae,P.virginianae,Periconia verrucose,Phomatospora uniseriata,Pleopunctum clematidis,Pseudocapulatispora clematidis,Pseudocoleophoma clematidis,Pseudohelminthosporium clematidis,Pseudolophiostoma chiangraiense,P.clematidis,Pseudomassarina clematidis,Ramusculicola clematidis,Sarocladium clematidis,Sclerenchymomyces clematidis,Sigarispora clematidicola,S.clematidis,S.montanae,Sordaria clematidis,Stemphylium clematidis,Wojnowiciella clematidis,Xenodidymella clematidis,Xenomassariosphaeria clematidis and Xenoplectosphaerella clematidis.The following fungi are recorded on Clematis species for the first time:Angustimassarina rosarum,Dendryphion europaeum,Dermatiopleospora mariae,Diaporthe ravennica,D.rudis,Dichotomopilus ramosissimum,Dictyocheirospora xishuangbannaensis,Didymosphaeria rubi-ulmifolii,Fitzroyomyces cyperacearum,Fusarium celtidicola,Leptospora thailandica,Memnoniella oblongispora,Neodidymelliopsis longicolla,Neoeutypella baoshanensis,Neoroussoella heveae,Nigrograna chromolaenae,N.obliqua,Pestalotiopsis verruculosa,Pseudoberkleasmium chiangmaiense,Pseudoophiobolus rosae,Pseudoroussoella chromolaenae,P.elaeicola,Ramusculicola thailandica,Stemphylium vesicarium and Torula chromolaenae.The new combinations are Anthodidymella clematidis(≡Didymella clematidis),A.vitalbina(≡Didymella vitalbina),Anthosulcatispora brunnea(≡Neobambusicola brunnea),Fuscohypha kunmingensis(≡Plectosphaerella kunmingensis),Magnibotryascoma rubriostiolata(≡Teichospora rubriostiolata),Pararoussoella mangrovei(≡Roussoella mangrovei),Pseudoneoconiothyrium euonymi(≡Roussoella euonymi),Sclerenchymomyces jonesii(≡Neoleptosphaeria jonesii),Stemphylium rosae(≡Pleospora rosae),and S.rosae-caninae(≡Pleospora rosae-caninae).The microfungi on Clematis is distributed in several classes of Ascomycota.The analyses are based on morphological examination of specimens,coupled with phylogenetic sequence data.To the best of our knowledge,the consolidated species concept approach is recommended in validating species.

The numbers of fungi:are the most speciose genera truly diverse?

Fungi play vital roles in ecosystems as endophytes,pathogens and saprobes.The current estimate of fungal diversity is highly uncertain,ranging from 1.5 to 12 million,but only around 150,000 species have been named and classified to date.Since the introduction of DNA based methods for species identification,the number of newly described taxa has increased from approximately 1000 to around 2000 yearly.This demonstrates the importance of DNA based methods to identify and distin-guish species,especially cryptic species.Many novel species from recent studies have been found in historically understudied regions and habitats,but these still represent only a small percentage of the estimated species.In this paper,we examine 16 genera from the top 40 most speciose genera as listed in Species Fungorum as case studies to examine the diversity of taxa in each genus.The genera treated herein are Cercospora,Diaporthe,Meliola,Passalora,Phyllachora,Phyllosticta,Pseudocer-cospora,Ramularia(ascomycetes)and Cortinarius,Entoloma,Inocybe,Marasmius,Psathyrella,Puccinia,Russula,Uromyces(basidiomycetes).We critically evaluate the number of species in these genera and correlate these numbers with the number of entries in GenBank.We introduce 18 new species Apiospora multiloculata,Candolleomyces thailandensis,Cortinarius acutoproximus,Cortinarius melleoalbus,Cortinarius pacificus,Cortinarius parvoacetosus,Diaporthe guizhouensis,Entoloma pseudosubcorvinum,Inocybe meirensongia,Marasmius albulus,Marasmius obscuroaurantiacus,Meliola camporesii,Phyl-lachora siamensis,Phyllosticta doitungensis,Picipes yuxiensis,Pseudocercospora vignae,Puccinia maureanui and Russula inornata.We also introduce a new record of Candolleomyces cladii-marisci and Inocybe iringolkavensis.We discuss the genera Colletotrichum and Pleurotus that are speciose,but do not occur in the top 40.We hypothesize whether there might be more species in these genera and discuss why these genera have some of the largest number of species.

The numbers of fungi:contributions from traditional taxonomic studies and challenges of metabarcoding

The global diversity of fungi has been estimated using several different approaches.There is somewhere between 2–11 million estimated species,but the number of formally described taxa is around 150,000,a tiny fraction of the total.In this paper,we examine 12 ascomycete genera as case studies to establish trends in fungal species descriptions,and introduce new species in each genus.To highlight the importance of traditional morpho-molecular methods in publishing new species,we introduce novel taxa in 12 genera that are considered to have low species discovery.We discuss whether the species are likely to be rare or due to a lack of extensive sampling and classification.The genera are Apiospora,Bambusicola,Beltrania,Capronia,Distoseptispora,Endocalyx,Neocatenulostroma,Neodeightonia,Paraconiothyrium,Peroneutypa,Phaeoacremonium and Vanakripa.We discuss host-specificity in selected genera and compare the number of species epithets in each genus with the number of ITS(barcode)sequences deposited in GenBank and UNITE.We furthermore discuss the relationship between the divergence times of these genera with those of their hosts.We hypothesize whether there might be more species in these genera and discuss hosts and habitats that should be investigated for novel species discovery.

Ten decadal advances in fungal biology leading towards human well‑being

Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being.In the current paper,we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research.These examples concern recently introduced drugs for the treatment of infections and neurological diseases;application of–OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production;as well as some highlights of mushroom cultivaton in Asia.Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs,are also given.In addition,two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided.Some other areas where there have been and/or will be significant developments are also included.It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.

One stop shopⅢ:taxonomic update with molecular phylogeny for important phytopathogenic genera:51–75(2019)

This is a continuation of a series focused on providing a stable platform for the taxonomy of phytopathogenic fungi and organisms.This paper focuses on 25 phytopathogenic genera:Alternaria,Capnodium,Chaetothyrina,Cytospora,Cyphellophora,Cyttaria,Dactylonectria,Diplodia,Dothiorella,Entoleuca,Eutiarosporella,Fusarium,Ilyonectria,Lasiodiplodia,Macrophomina,Medeolaria,Neonectria,Neopestalotiopsis,Pestalotiopsis,Plasmopara,Pseudopestalotiopsis,Rosellinia,Sphaeropsis,Stagonosporopsis and Verticillium.Each genus is provided with a taxonomic background,distribution,hosts,disease symptoms,and updated backbone trees.A new database(Onestopshopfungi)is established to enhance the current understanding of plant pathogenic genera among plant pathologists.

What is a species in fungal plant pathogens?

Scientific names are crucial for communicating knowledge concerning fungi and fungus-like organisms.In plant pathology,they link information regarding biology,host range,distribution and potential risk to agriculture and food security.In the past,delimitation among pathogenic taxa was primarily based on morphological characteristics.Due to distinct species sharing overlapping characteristics,the morphological identification of species is often neither straightforward nor reliable.Hence,the phylogenetic species concept based on molecular phylogenetic reconstructions gained importance.The present opinion discusses what a fungal species is and how identification of species in plant pathology has changed over the past decades.In this context,host-specialization and species complexes are discussed.Furthermore,species concepts in plant pathology are examined using case studies from Bipolaris,Colletotrichum,Curvularia,Diaporthe,Diplodia,Meliola,Plasmopara,rust fungi and Trichoderma.Each entry contains a brief introduction to the genus,concepts used in species identification so far and the problems in describing a species followed by recommendations.The importance of correctly naming and identifying a species is addressed in the context of recent introductions,and we also discuss whether the introduction of new species in pathogenic genera has been overestimated.We also provide guidelines to be considered when introducing a new species in a plant pathogenic genus.