The Identification Of Pathogen Fungi Causing Jujube Fruit Diseases And Diversity Of Alternaria Pathogens

In recent years, both the types and harm of jujube fruit disease areincreasing, the jujube trees even had lost all harvests when some disease are serious.There is a phenomenon that same fruit diseases or pathogen with different names havebeen reported. Confusion and uncertainty of jujube fruit disease name and pathogenspecies bring the obstacle to predict, prevention, control and academic exchanges ofthe jujube disease. This paper systematically investigated the jujube fruit diseaseswhich are all happened frequently in the mainly produced jujube district(Xinzheng ofHenan,Puyang, Dengfeng, Alar of Xinjiang and Zhanhua of Shandong etc.). It haveobserved the symptom characteristic and disease situation in different jujubemainly-produced district in China. We isolated, purified and preserved the mainlypathogen, also tested the pathogenicity and identified the pathogens with morphologyand molecule sequences. We have isolated and indentified8species of pathologicalfungi and few uncertain fungi. Fusarium proliferatum and Fusarium oxysporum cancause soft rot symptom in the field is first discovered and proved. And we alsoisolated Alternaria yaliinficiens R.G. Roberts from Xinzhen shrink fruits in the firsttime. Total56Alternaria sp. specimen which could cause jujube fruit disease havebeen analysed by ISSR genetic diversity. This study lays the foundation for theaccurate identification of jujube fruit disease, pathogenic regularity and scientificprevention and control research. At last, we had got the detailed test result as follows:1．Collection of jujube fruit diseases in the mainly produced jujube district andarranging with identification the isolated strains2011-2012, we collected16lots, more than200specimen from Xinzheng jujubeof Henan, Puyang bianhesuan, Dengfeng winter jujube and lizao, Shijiazhuangbianhesuan of Hebei, Cangzhou jinsixiaozao, Xinjiang Alar huizao, Akesu Junzao,Zhanhua winter jujube of Shandong and Tai’an winter jujube etc. We isolated andpurified the fungi from the diseased fruits’ tissue and preserved the pathogens. Theseisolates were inoculated back to fresh jujubes both in room and farmland, then testedthe pathogenicity and identified the isolated fungi. We finally got483strains. Thenthere were256strains which can cause the disease after precisely certified by Koch’sRule. At last, we indentified the pathogenic fungi according to the fungus’ traditionalmorphology characteristic combined with modern molecule identification method.2.6species of jujube fruit disease samplesThe collected disease fruit mainly focused on six kinds of diseases symptoms:jujube shrink disease, soft rot disease and black spot disease in Puyang of Henan;anthracnose disease and soft rot disease in Xinzheng;black spot disease and ring spotdisease in Dengfeng; small spot disease in Alar of Xinjiang.3.Identification of fungi pathogens of jujube fruit diseasesThe jujube shrink pathogen variety is very complicated, except already reported Fusicoccum aesculi Corda, Phoma glomerata, and Alternaria alternate(Fr.) Keisslerand Alternaria tenuissima(Fr.) Wiltshire. This research also isolated Alternariayaliinficiens R.G. Roberts and this new pathogen didn’t cause the typical jujube shrinkdisease during the test of inoculation individually, but pathogenicity was obviouslyhigh after inoculating Colletotrichum gloeosporioides and Alternaria spp. wereisolated from the jujube anthracnose disease when inoculating in the farmland,Alternaria spp. caused black hollow spot. Three fungi pathogens which caused thesoft rot disease were isolated, they are Fusarium proliferatum, Fusarium oxysporumand Fusicoccum aesculi Corda. Fusarium proliferatum and Fusarium oxysporum cancause soft rot symptom in the field is first discovered and proved. From the jujubeblack spot disease fruits, we got Alternaria yaliinficiens R.G. Roberts and Fusicoccumaesculi Corda, this is not similar to the before reports. In Xinjiang jujube small spotdisease, we isolated Alternaria alternate (Fr.) Keissler and Alternaria tenuissima(Fr,)Wiltshire. From the jujube ring spot disease, we got both Alternariatenuissima(Fr.)Wiltshire and Alternaria yaliinficiens.R.G.Roberts. as to the Alternariaspp.4.The study of Alternaria spp. fungi pathogens caused jujube fruit diseases byusing ISSR technique and molecular identificationWe chose56Alternaria strains which can bring disease, and analysed the ISSRgenetic diversity, the result shows: we cannot effectively distinct the alreadyconfirmed Alternaria spp. from the phenotype, in different geography regionalism,the strains in Puyang and Shandong district can be roughly put into one independentgroup, but in Xinzheng, Dengfeng, Shijiazhuang and Xinjiang district, it’s confusedand cannot group them clearly. We also compared the rDNA ITS and OPA2-1sequence of those Alternaria spp., the result shows these two genes both cannoteffectively identify those Alternaria spp.. So the result can prove that those smallspore Alternaria spp. have high resemblances in the genetic information.