The Identification And Phylogenetic Analyses For Fungal Pathogens Of Mainly Orchidaceae In Southwest Of China

Orchidaceae is the second largest amount of plants to Asteraceae with high ornamental and medicinal value.Orchidaceae cultivation conditions are so harsh that its growth vulnerably and cultivation uneasily from external factors interfere and destruction.In recent,with developing based on its value of ornament and medicine rapidly,many natural reserve bases of Orchidaceae were established in domestic and overseas,And many large-scale Orchids markets were built also.However,during cultivating Orchids,the pest from insects,fungi,bacteria are most important factor to effecting plants growth.Insects mainly destroyed the plants,Diseases were more serious by pathogen,dominantly besides fungi,bacteria and virus.Meanwhile,fungi were one of the most serious and common infecting microbes,which is seriously effectively the value of Orchidaceae.Therefore,the work is especially significance that identification of pathogenic fungi identification on Orchidaceae.The research provided a theoretical basis to security cultivation of Orchidaceae effectively as well.The total 92 samples,including Dendrobium nobile Lindl,Bulbophyllum Thou,Cymbidium lancifolium Hook.,Gastrodia elata Bl.,Vanda etc.,.were collected in Orchidaceae protection bases of respectively Chongqing Prov.,Guangxi Prov.and Guizhou Prov.from 2015 to2016.The phylogenetic analytic tree generated by the software PAUP with performing the method of Maximum Parsimony.Neopestalotiopsis sp.and Pestalotiopsis sp.were identified in according with combined gene ITS,?-tubulin and TEF.But six genes ITS,GPD,CHS-1,HIS-3,?-tubulin and Actin were used to classify Colletotrichum sp..And morphologic characteristics also were used to exactly identify pathogen in Orchidaceae.The result indicated that 15 strains,belonging to Neopestalotiopsis,conclude two new species(N.cymbidiumis,N.lancifoliumis),seven reported species(N.ellipsospora,N.samarangensis,N.foedans,N.asitica,N.surinamensis,N.saprophytica,N.clavispora),one China new recording species(N.protearum);27 strains were consisted of Pestalotiopsis sp.,two China new recording species(P.chamaeropis,P.rosea),one reported species P.trachicarpicola;and 12 strains were identified as Colletotrichum sp,five undefined.Pathogens were recognized based on phylogeny and morphology.In according with taxonomic analyses in research,the genus Neopestalotiopsis easily caused Orchidaceae diseases and distributed widely in southwest of China,because lots of species of Neopestalotiopsis were collected from the type of plant(N.ellipsospora,N.samarangensis,N.foedans,N.asitica,N.surinamensis,N.saprophytica,N.clavispora,N.cymbidiumis sp.nov.,N.lancifoliumis sp.nov.).However,Pestalotiopsis(P.chamaeropis,P.rosea,P.bulbophylli,P.trachicarpicola)and Colletotrichum sp.have widespread distribution,but few of species could be isolated from diseased Orchidaceae in this area.All the holotype of new species identified in our research are coserved in Plant Pathology Lab,Guizhou University.