Study Of Phoma In Northeast China

The host range of Phoma is very wide,which endangers hundreds of species of medicinal plants,ornamental plants and cash crops,and can infect all parts of the host.Resulting in a decline in crop yield,quality decline,and even death,resulting in huge economic losses.In this paper,the diseases caused by stem mildew in Northeast China were collected and studied.In this experiment,69 species of diseases belonging to 31 families were collected from 8 areas in three provinces of Northeast China.The above disease specimens and 4 strains not identified in the laboratory were identified.Finally,18 strains related to Phoma were obtained,which were distributed in 2 genus and 10 species,respectively: Phoma: P.rhei?P.pomorum?P.americana?P.exigua?P.commelinicola?P.plurivora?P.glomeratum?P.fungicola,a new record species in China is P.plurivora;There are 10 new record hosts in China,which are P.bellidis(living Heracleum hemsleyanum Diels?Aralia mandshrica),P.pomorum(Atractylodes Lancea(Thunb.)DC.),P.americana(Rosa rugosa Thunb.,Veronicastrum sibiricum(L.)Pennell),P.exigua(Glycine max(Linn.)Merr.,Cynanchum atratum,Paeonia lactiflora Pall,Chenopodium quinoa Willd),P.fungicola(Parthenocissus quinquefolia(L.)Planch);Boeremia: B.exigua var.pseudolilacis,B.exigua var.linicola,A new record species from China is B.exigua var.pseudolilacis;A new record host in China: B.exigua var.linicola(Panax ginseng)?In this study,the fungi were identified by internal transcriptional spacer(ITS),ribosomal large subunit(LSU),?-tubulin gene(tub2),RNA polymerase II(rpb2)and actin gene(ACT).At the same time,37 ITS sequences,37 Tub2 gene sequences,30 ACT gene sequences,35 LSU gene sequences and 30 rpb2 gene sequences were obtained by molecular sequence supplement,subsequent identification and proofreading of strains that had not been identified in the laboratory and those lacking partial primer sequences.Finally,37 strains related to Phoma were sorted out,including 5 genus and 21 species.The biological characteristics of 9 isolates isolated from Aralia mandshrica?Veronicastrum sibiricum and Atractylodes Lancea were studied.The following conclusions were drawn: the most suitable medium for the hyphal growth of the above isolates was PDA,CA and PSA.The optimum temperature was 25?,the optimum pH was 7,the optimum light condition was full light,the optimum carbon source was glucose,and the optimum nitrogen source was peptone.The most suitable medium for sporulation was OA medium,the optimum temperature was 25?,the optimum pH was 7,the optimum light condition was full light,the optimum carbon source was mannitol,and the optimum nitrogen source was peptone.The optimal environment for the survival of Phoma is clarified,which provides a theoretical basis for the identification and prevention of Phoma in the future.