Phylogeny And Taxonomy Of Melanconium Sensu Lato In China

Melanconium sensu lato are opportunistic pathogens and endophytic fungi.They have been found to be confined to the host family Betulaceae,Juglandaceae etc.from Europe,North America and Asia.Melanconium sensu lato are responsible for dieback of the host trees,which can lead to significant economic and ecological losses.Recent studies indicated Melanconium sensu lato refer to at least three families of Diaporthales.Due to the lack of available type specimens,ex-type strains and the similarity of the morphology,the relationship between anamorphs and teleonorphs caused confusions over a long period time.Furthermore,the poor taxonomic system makes great difficulties to species identifications,diagnosis and the control of fungal diseases.Therefore,the present study aims to collect fresh specimens,reveal species boundaries and clarify host ranges,using morphological and molecular phylogenetic analyses.A total of 254 specimens were collected from nine Provinces of China.Morphological observation includes the features of fruit bodies,conidia,ascospores and cultural characteristics.All phylogenetic analyses were performed through MP,ML and Baysian methods,combined two ribosomal genes and three coding proteins genes to analyze the relationship among Melanconium sensu lato.The main results in the current study are as follow:1.Confirmed morphological key to Melanconium sensu lato.The feature of conidiomata,two types of conidia and the arrangement of the ascospores have been proved to be stable for the delimitation of three Melanconium related genus.Different species can be distinguished by the absence of central or eccentric stromatic column,shape of conidia and the presence or absence of sheath.According to these morphological characteristics the current study confirmed a total of 8 Melanconium related species in 3 different genera.2.Analyze the connections and evolutions in Melanconium sensu lato.The current results indicated that ITS,LSU,cal,rpb2 and tef1-? genes have significant inter-and intra-distance,which can be used for different classes of Melanconium related fungi.The phylogenetic clades and morphological groups showed to be high consistency.3.Explore the anamorph-teleomorph connections in Melanconium sensu lato.The current study proved that teleomorph of Melanconium refer to at least three genus in different families,i.e.Melanconis of Melanconidaceae,Melanconiella of Melanocniellaceae,Juglanconis of Juglanconidaceae.We also suggested that the DNA sequence and host affiliation could confirm the relationship between anamorphic and teleomorphic state of Melanconium like fungi.4.Describe eight Melanconium sensu lato,which belongs to three different families of Diaporthales.Include Juglanconis juglandina,J.oblonga,Melanconiella betulicola,M.cornuta,M.corylina,Melanconis betulae,Melanconis.itoana and Melanconis.stilbostoma.Four new species were introduced:Melanconiella betulicola,M.cornuta,M.corylina and Melanconis betulae.The current study certified the biodiversity of these taxa and revised the taxonomy of Melanconium sensu lato in China.