Phylogenetic Analysis Of Colletotrichum On Landscape Plant In Sichuan Province And Its Indoor Drug Screening

Colletotrichum is a kind of fungus widely distributed in the world,which can harm various cash crops and cause serious losses.This test in order to further clear landscape plant in Sichuan province Colletotrichum pathogen species,as to provide theoretical basis for prevention of Colletotrichum.A total of 265 samples of anthracnose were collected from more than 120 garden plants in 14 urban areas,including Deyang City,Mianyang City,Neijiang City and Luzhou City,and Colletotrichum strains were obtained by tissue isolation and monosporal purification.After morphological characteristics and polygenic molecular identification,200 strains can be accurately identified.The main results are as follows:200 Colletotrichum strains were identified by GAPDH gene and could be divided into 7 categories.Then the 35 strains of Colletotrichum selected from gloeosporioides complex species were identified as 4 species by using 6 gene sequences of ITS,GAPDH,ACT,TUB,CHS and ApMat.Five genes of ITS,GAPDH,ACT,TUB and CHS were used to identify 26 other strains,and 9 species were identified,one of which was not clearly identified.The number of c.siamense was the highest in all the tested strains,which accounted for 39% of the total bacteria,which was the dominant species.From each region,C.siamense is also the dominant fungi in southwest Sichuan,south Sichuan and central Sichuan,while C.gloeosporioid is the dominant fungi in north Sichuan.The results of pathogenicity test showed that all of the 14 strains could cause disease to apple and citrus.Except for C.gigasporum,C.kahawae and C.spaethianum,which are not pathogenic to pepper,other colletotrichum can cause disease in peppers.The most pathogenic bacteria are: C.siamense,C.gloeosporioide,C.lirios and C.fiorinia.The results showed that the order of inhibitory effect on most Colletotrichum species was as follows: pyrazole(98.1%)> prochloramil(96.1%)> tebuconazole(97%)>Phenyletherazole(96%)> thiophanate(97.5%)> mancozeb(80.5%).Based on the analysis of four species of anthrax with high coverage,and the best inhibition agent for C.siamense,C.karstii and C.fructicola was pyrazole ethers,while the best for C.gloeosporioides inhibition was prochloramil.It was found that the susceptibility of the pathogen to fungicides was not related to the growth rate of the pathogen.The inhibition effect of mancozeb on spores germination of Colletotrichum was the best,which was contrary to that of mancozeb on mycelium growth of Colletotrichum.For comprehensive analysis,tebuconazole is recommended as the preferred agent,and prochloraz and pyraclostrobin can be used interchangeably.