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Molecular Phylogenetic Study Of Plant Pathogenic Fungi Of The Family Didymellaceae In Southwest China

Posted on:2022-10-26Degree:MasterType:Thesis
Country:ChinaCandidate:J YuanFull Text:PDF
GTID:2510306527471774Subject:Plant protection
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Didymellaceae is an important fungi widely distributed all over the world,which exists in various geographical environments in many forms,such as plant pathogens,endophytes,saprophytes etc.Overwhelming majority the species in Didymellaceae have plant pathological importance and are entry quarantine species of plants in each countries and regions.In addition,they are potential to be used as biological control agents.There are many unknown species in Didymellaceae,geting a good understanding of the species and the biodiversity of Didymellaceae in the southwest of China.In this study,a host of diseased leaves of plants were collected.Based on the molecular phylogeny and morphology,the taxonomic status of pathogenic fungi was identified.In this study,57 isolates of Didymellaceae were isolated from plant specimens collected in southwest China(Guizhou,Yunnan,Sichuan,Guangxi,etc.)during 2018 to 2020.The strains were identified by the combination of phylogenetic analysis of four genes(ITS,LSU,rpb2 and tub2 gene regions)and morphological analysis.The results showed that 57 isolates of Didymellaceae were found in 8 genera:Allophoma(8),Ectophoma(8),Heterophoma(3),Stagonosporopsis(3),Boermia(1),Nothophoma(7),Epicoccum(11),Didymella(16).A total of 11 species were identified,including 3 new species named Allophoma thunbergiae,Stagonosporopsis actinidiae,Heterophoma capsicus;8 known species are Allophoma pterospermicola,Allophoma tropica,Ectophoma iranica,Ectophoma multirostrata,Nothophoma brennandiae,Epicoccum latusicollum,Epicoccum cedri,Didymella sinensis;2 new records of China were identified;3 suspected new species to be further identified and 26 undetermined species.The pathogenicity of some strains was determined by Koch's rule.After inoculating the plant,the same pathogen was isolated again,which indicated that the isolated strain was the pathogen of the plant.In this experiment,four plant pathogens were isolated and verified,and two new record species in China were identified.This is the first time that molecular systematics has been applied to identify,classify and revise the Didymellaceae fungi in Southwest China.The results show that the phylogenetic relationship of Didymellaceae in southwest China is distinct,and new species with plant pathological importance are found,this study provides important theoretical guidance for the prevention and control of diseases caused by Didymellaceae.
Keywords/Search Tags:Didymellaceae, Morphology, Multi-gene locus, Phylogeny
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