Study On The Diversity Of Anthracnose Fungi Of Plum And Other Garden Plants In Wuhan

Anthracnose is a kind of important plant disease with a worldwide distribution and causes severely losses to plants especially in tropicaltorrid and semi-tropical zone.Many species of fungi can cause crop anthracnose among which Colletotrichum gloeosporioides is the most important and devastating species on plant pathogen with wide host range.In this study,323 isolates of Colletrichum sp.were isolated from plum showing Anthracnose collected from Wuhan,Hubei province.The isolates were classfied into 7 groups according to their biological characteristics,such as colony morphology,pigment, the morphology,size of spore and conidiophore.All the 7 groups could infect fruit trees tested which beong to Rosaceae with different pathogenicy to different kinds of fruit trees, while could not form any visible lesions on plants belonging to other families.Isolates from all groups were identified as C.gloeosporioides based on ITS sequence,although there were great diversity on biological characteritics and pathogenicity.RAPD analysis indicated that there existed great genetic diversity among 36 isolates selected from 7 groups.The dendrogram showed that they could be divided into 2 groups when the similarity lever was 53%.TypeⅠcomprised 29 isolated,namely M9-1,M4-1, 11-2,N23-2,M9-2,M22,H44-1,M11-1,M17,H43-2,H43-1,M100,M24,Ml19-1,N9, N36-2,N46,NI-1,N47,N14-1,H35-1,M110,M47,H40-2,H11-1,M1-3,M12-2,N43-2, and M85.TypeⅡcomprised M20,H32-1,M105,M70,M48,M57-2,and M10-1.The two-type was not consistent with the 7-group,nor with the pathogenicity.The results suggested that different isolate of C.gloeosporioides screened from the same host plum showed great diversity on biological characteritics and on genetic characteritics.Seventy eight isolates of Colletotrichum sp.were obtained from 10 kinds of horticultural plants includes fruit tree,vegetable and flower plants.12 isolates were identified by biological characteristics and ITS sequence.One isolate from pepper was identified as C.acutatum.and one isolate from strawberry as C.fragariae.The others were identified as C.gloeosporioides.A sample showing strawberry leaf spot was collected,The pathogen CM-6 was identified as Dendrophma obscurans based on its morphology characteristics and ITS sequence molecular informat.CM-6 isolate could grow at 10-40℃and sporulate under the temperature at 15-35℃,respectively.Under the optimal temperature,the illumination could promote the mycelium growth and sporulation.The opitmal temperature for growth and sporulate was 25-30℃.The isolate could grow under pH were 3-10 and pH 6 was the most optimal value.The isolate could sporulate under pH 4-9 and 6-7 was the most optimal pH value.