Species Diversity Of Endophytic Colletotrichum In Aquatic Plants And Eupatorium Adenophorum

Colletotrichum as important plant pathogens can cause many crops and fruits trees infected,resulting in plant stems,leaves,flower and fruit appeared local sunk and necrotic lesions,which has the characteristics of rich species,wide hosts and distribution range.Meanwhile,Colletotrichum has been widely reported as endophytic pathogens.However,most of endophytic Colletotrichum are identified to genus.Therefore,itis not conducive to study the function of endophytic Colletotrichum and further reveal the relationship between endophytic Colletotrichum and pathogen Colletotrichum.In this study,Colletotrichum were mainly isolated from healthy aquatic plants and Eupatorium adenoph.orum in Yunnan,Sichuan,and Guizhou Province,and were identified based on morphological description and molecular Phylogenetic analysis.Furthermore,the suspected new Colletotrichum strains were used to pathogenicity tests.The aim was to study the species diversity of Colletotrichum from aquatic plants and Eupatorium adenophorum,and to detect whether the Colletotrichum could had pathogenicity to other plants.The results were as follows:1.In aqustic plants,1697 strains of endophytes were isolated from aquatic plants,only 66 strains were endogenous Colletotrichum,which did not belong to dominant fungi.Colletotrichum could be obtained from different parts of aquatic plants,which the isolation frequency from roots was 21.0%,isolation frequency from stems was 46.8%,and that of leaves was 32.3%.In addition,883 strains of endophytes were isolated from Eupatorium adenophorum,in which 64%were endogenous Colletotrichum,belonging to the dominant genera,and mainly existing in plant leaves.2.66 strains of endogenous Colletotrichum were isolated from aquatic plants.After identifing based on morphological description and molecular phylogenetic analysis,obtained 6 known species,including C.boninense,C.fructicola,C.siamense,C.kahawae,C.karstii,C.guajavae,16 new species:C.vulgaris,C.baiyuensis,C.spicatum,C.dianchiensis,C.fuxianhuensis,C.philoxeroides,C.demersum,C.kasahuensis,C.litangensis,C.sinensis,C.tenchongensis,C.wuxuhaiensis,C.kunmingensis,C.xishuangbannaensis,C.menglunensis,Cmenglaensis.The emergence of new species of high frequency indicates that water and endophyte are the main factors leading to the differentiation of Colletotrichum species.562 strains of endogenous Colletotrichum were separated from Eupatorium adenophorum,including 9 known species C.boninense,C.gloeosporioides,C.simmondsii,C.siamense,C.tropicale,C.fructicola,C.coffeanum,C.brevisporum,C.incarnatum and so on.And 5 new species were identified,which were C.adenophorum,C.gengmaensis,C.cangyuanensis,C.lincangensis,C.simaoensis.Among the endogenous Colletotrichum isolated from aquatic plants and Eupatorium adenophorum,3 of the known species are overlapping:C.boninense,C.fructicola and C.siamense,indicating that the same species of endogenous Colletotrichum can be found in a variety of plant hosts.3.17 Colletotrichum strains(C.vulgaris,C.baiyuensis,C spicatum,C.dianchiensis,C.fuxianhuensis,C.philoxeroides,C.litangensis,C.tenchongensis,C.wuxuhaiensis,C.kunmingensis,C.xishuangbannaensis,C.menglunensis,C.menglaensis,C.adenophorum,C.gengmaensis,C.cangyuanensis,C.lincangensis)were tested the pathogenicity in five different fruits,including strawberries,grapes,oranges,tomatoes and blueberries.The result indicated that the pathogenicity of different Colletotrichum to the same fruit was different,and the pathogenicity of the same stain to different fruits was also different.Moreover,the 17 strains were all endophytes isolated from healthy plants,after inoculation,the surface of the fruits showed defferent degrees of Colletotrichum symptoms,it demonstrated that these fungi were pathogens to the furits.Therefore,we speculated that Colletotrichum might have different functions in different hosts and environments conditions.