| Camellia oleifera anthracnose was one of the most important plant diseases and could had bad influences on the quality and yield.Before the year of 2014,we considered the Colletotrichum gloeosporioides as Camellia oleifera anthracnose.It showed that new Camellia oleifera anthracnose appeared which were Colletotrichum fructicola and Colletotrichum siamense in the last two years.In order to define Camellia anthracnose pathogen and analysis the genetic diversity,we gathered the diseased leaves of 16 varieties of Camellia oleifera from Fenyi,Jiangxi Province.Then we isolated strains from these leaves.We studied these isolates by using phylogenetic which based on ITS,CAL and GAPDH sequence.And we also studied their morphology and pathogenicity.The results were as follows:(1)Camellia oleifera anthracnose hereditary diversity in fine-scale.292 strains of anthracnose pathogen were identified as 6 species based on multi-gene phylogenetic,which included C.fructicola,C.gloeosporioides,C.siamense,C.boninense,C.sp1 and C.sp2.The feature of the colony,conidia and appressoria were varied from different strains,which means that Camellia oleifera anthracnose had morphology diversity.Among the isolates,247 isolates were identified as C.fructicola which was the dominant species with the ratio of 84.59%;20 isolates were identified as C.gloeosporioide;19 isolates were identified as C.siamense;C.boninense was the first report on Camellia oleifera,and we found 3 isolates in this speices.We only found one isolate of C.spl.and two isolates of C.sp2.We found that different genetic markers to different kinds of anthrax resolution was not the same through the NJ phylogenetic tree of Colletotrichum spp.based on different sequences.The muti-gene was better than singlten gene in reveal the interspecies and intraspecific genetic differentiation.(2)The thesis studied the relation between camellia varieties and separated from the varieties.According to the research of 16 Camellia varieties,Colletotrichum anthracnose existed in all of the varieties.The morbidity and disease index was very high.The pathogenicity of different species was:C.fructicola>C.gloeosporioides>C.siamense>C.boninense>C.sp2>C.spl.However,the genetic changes of the strains could not completely represent the change of pathogenicity.The pathogenic had a certain differentiation,which meant that different strains of the same species,may appeared different pathogenic.And different strains might not only infect different camellia varieties,but also might infect the same ones.C.fructicola distributed in all of the 16 varieties,C.gloeosporioides distributed in 12 varieties and C.siamense distributed in 10 varieties.C21 had the biggest amount of strains and species which consisted of 4 species and 22 strains.But it did not mean that the bigger the amount,the more the species.For example,X1 had the smallest amount of strains,but it included 3 species which was the second amount of species.From the above,it showed that different Camellia varieties had some preferences for different strains but did not have the obvious effect on genetic level.(3)The thesis studied the genetic diversity of Camellia anthracnose advantage variety C.fructicola.The genetic analysis of 247 strains identified total of 21 ITS-CAL-GAPDH haplotypes.Two of them were the major haplotypes distribute from almost all of 16 varieties sites.Haplotype 2 included 135 sequences,accounting for 54.7%of the total,was the dominant and original haplotype.Each species had its own unique haplotypes.The coefficient of genetic differentiation(Fst)indicated that there was a certain genetic differentiation between strains of different varieties of population.Neutrality Tests and mismatch distribution analysis suggested that there existed large population expansion for C.fructicola.The multi-gene phylogenetic analysis showed that strians from different varieties scattered distribution in the phylogenetic tree.This showed that the gene exchange was frequent among the strains of different varieties,and there was no isolation of the varieties,and it also showed that Camellia oleifera Colletotrichum anthracnose had highly genetic diversity. |
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