| The genus Cytospora is ubiquitous and causes devastating canker diseases in the world,which results in great damage to infected forests and seriously threatens ecological safety.Xinjiang Uygur Autonomous Region situated in the hinterland of Eurasia,and it has unique forest resources with the geomorphic features of"two basins and three mountains".Temperate and monsoonal climate has made the canker disease cause huge damage and pose severe influence on environmental improvement and economic development of Xinjiang.The understanding of Cytospora in Xinjiang was little.In order to expand our knowledge on species and complexity of Cytospora in Xinjiang,this study collected the specimen,characteized their damage symptoms on hosts,investigated morphological features such as the type of stroma,the number of ostiole,the shape of locule,the size of conidia and cultural characteristics.Meanwhile,using multiple DNA fragments,the phylogenetic dendrogram was constructed to analyze the phylogeny and genetic relationship of Cytospora species on different hosts and geographical origins.The main conclusions in the current study are below.1.Twenty-one Cytospora species in Xinjiang were described,among which 6 kinds species needed to be published,C.cotini,C.parastica are new records in China.C.carbonacea,C.cincta,C.populina,C.pruinopsis,C.sophoricola were the first collected in Xinjiang.2.Cytospora species were firstly discovered parasitizing Xanthoceras sorbifolia and Spiraea hypericifolia.25 of Cytospora species were new host records in China.3 geographical distribution location of Cytospora species in China and 15 geographical distribution location in Xinjiang were added.Clarify C.chrysosperma is the most widely distributed and the most harmful species in Xinjiang.3.Clarify the classification basis is the type of locule,black conceptacle and the number of ostiole.21 Cytospora species were divided into 8 morphocluster.Based on the feature of single locule,C.pruinopsis was divided into cluster one;Based on the feature of black conceptacle,C.sp5 was divided into cluster two and C.cincta,C.leucostom and C.nivea were divided into cluster three;Based on the feature of without black conceptacle and multi-ostiole,C.populina was divided into ?,C.schulzeri,C.hippophaes,C.germanica,C.elaeagni,C.sophoricola were divided into V and C.carbonacea was divide into ?;based on the feature of without black conceptacle and with single locule,C.chrysosperma,C.parasitica,C.spl were divided into ? and C.ambiens,C.sp2,C.sp3,C.sp4,C.sp6,C.cotini were divided into ?.4.The phylogenetic dendrogram was constructed based on ITS gene fragment and ITS,LSU,tef-la gene fragment by NJ method.The results showed that C.ambiens and C.mali can be clear distinction through gene with multiple DNA fragments,further shows that gene with multiple DNA fragments is more suitable for the identification of Cytospora species.5.The phylogenetic analysis consists of MP,BI,ML based on multiple DNA fragments showed that each species of Cytospora species formed a single branch and the approval rating be relatively high(99-100%).But topological structure of phylogenetic dendrogram constructing with different methods existed differences,the topological structure of ML and MP is similar,and formed 3 branches,among which C.cincta formed a single branch,C.leucostoma,C.nivea and C.sp5 formed a branch and bootstrap support is 100%.Phylogenetic dendrogram based on BI formed 4 branches,C.germannica,C.sp6 formed 2 single branches.The phylogenetic dendrogram based on multi-methods can proof the reliability of results.6.Through contrasting the morphological groups and molecule branches,C.pruinopsis with the feature of single locule,cluster ? and cluster ? with black conceptacle(C.sp5,C.nivea,C.leucostoma)formed a single branch in the molecular phylogenetic tree.C.ambiens and C.sp6 in the same branch(?)have the same feature that locule arranged regularly.Mutual confirmation of morphological feature and multi-gene fragments can more exactly identify the species of Cytospora species. |
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