Improving ITS sequence data for identification of plant pathogenic fungi

Plant pathogenic fungi are a large and diverse assemblage of eukaryotes with substantial impacts on natural ecosystems and human endeavours.These taxa often have complex and poorly understood life cycles,lack observable,discriminatory morphological characters,and may not be amenable to in vitro culturing.As a result,species identification is frequently difficult.Molecular(DNA sequence)data have emerged as crucial information for the taxonomic identification of plant pathogenic fungi,with the nuclear ribosomal internal transcribed spacer(ITS)region being the most popular marker.However,international nucleotide sequence databases are accumulating numerous sequences of compromised or low-resolution taxonomic annotations and substandard technical quality,making their use in the molecular identification of plant pathogenic fungi problematic.Here we report on a concerted effort to identify high-quality reference sequences for various plant pathogenic fungi and to re-annotate incorrectly or insufficiently annotated public ITS sequences from these fungal lineages.A third objective was to enrich the sequences with geographical and ecological metadata.The results-a total of 31,954 changes-are incorporated in and made available through the UNITE database for molecular identification of fungi(http://unite.ut.ee),including standalone FASTA files of sequence data for local BLAST searches,use in the next-generation sequencing analysis platforms QIIME and mothur,and related applications.The present initiative is just a beginning to cover the wide spectrum of plant pathogenic fungi,and we invite all researchers with pertinent expertise to join the annotation effort.

Notes for genera:Ascomycota

Knowledge of the relationships and thus the classification of fungi,has developed rapidly with increasingly widespread use of molecular techniques,over the past 10–15 years,and continues to accelerate.Several genera have been found to be polyphyletic,and their generic concepts have subsequently been emended.New names have thus been introduced for species which are phylogenetically distinct from the type species of particular genera.The ending of the separate naming of morphs of the same species in 2011,has also caused changes in fungal generic names.In order to facilitate access to all important changes,it was desirable to compile these in a single document.The present article provides a list of generic names of Ascomycota(approximately 6500 accepted names published to the end of 2016),including those which are lichen-forming.Notes and summaries of the changes since the last edition of‘Ainsworth&Bisby’s Dictionary of the Fungi’in 2008 are provided.The notes include the number of accepted species,classification,type species(with location of the type material),culture availability,life-styles,distribution,and selected publications that have appeared since 2008.This work is intended to provide the foundation for updating the ascomycete component of the"Without prejudice list of generic names of Fungi"published in 2013,which will be developed into a list of protected generic names.This will be subjected to the XIXth International Botanical Congress in Shenzhen in July 2017 agreeing to a modification in the rules relating to protected lists,and scrutiny by procedures determined by the Nomenclature Committee for Fungi(NCF).The previously invalidly published generic names Barriopsis,Collophora(as Collophorina),Cryomyces,Dematiopleospora,Heterospora(as Heterosporicola),Lithophila,Palmomyces(as Palmaria)and Saxomyces are validated,as are two previously invalid family names,Bartaliniaceae and Wiesneriomycetaceae.Four species of Lalaria,which were invalidly published are transferred to Taphrina and validated as new combinations.Catenomycopsis Tibell&Constant.is reduced under Chaenothecopsis Vain.,while Dichomera Cooke is reduced under Botryosphaeria Ces.&De Not.(Art.59).