| Blueberry is a new kinds of fruit tree,and it is healthy and tasty.The fruits contents of polyphenols,anthocyanin and flavonoid-rich fraction,and blueberry can also reduce the incidence of diseases,such as cardiovascular disease and ageing.Blueberries are becoming more and more popular in China,Diaporthe stem canker is one of a serious fungal disease of blueberries,infects blueberry stems by entering through an opening and inducing a stem dieback that may lead to the death of the entire bush.Diaporthe stem canker is one of the primary factors limiting blueberry production of China.the objective of this study was to further identify and characterize the species of Diaporthe associated with Vaccinium spp.in China by analysis of morphology and nucleotide sequences of two genomic regions.Design a pear of Species-Specific PCR primer for the identification and detection of Diaporthe stem canker.Ten cultivars of blueberry were selected to study their pathogenicity.The results were summarized as follows:1.Symptomatic stems were collected from major plantings of blueberry in China between 2014 and 2016,the Sampling locations included Longyan of Fujian province,Shangrao of Jiangxi province,Xinchang of Zhejiang province,Chengdu of Sichuan province,Dalian and Dandong of Liaoning province Yichun of Heilongjiang province.52 isolates of Diaporthe spp.were obtained,actively growing sherns of blueberry were selected to study their pathogenicity,all isolates were pathogenic.2.The combined Diporthe EF1-a and ITS sequencedata were employed to MP analysis and BI analysis respectively,and identificated with the characterization of the isolates.There are at least 5 species in these isolates,2 species of Diaporthe were identificated.There have 8 strains could not be identified.By the identification of this study Diaporthe phaseolorum is one of the pathogenys of blueberry stem canker.Diaporthe phaseolorum included 1 isolates from Longyan,1 isolates from Yichun,2 isolates from Dandong,3 isolates from Dalian.This is the first report of D.phaseolorum causing diseases on blueberry.Another pathogeny of blueberry stem canker were identified as D.hongkongensis in this paper.Isolates were from Shangrao of Jiangxi province,Xinchang of Zhejiang province,and Longyan of Fujian province.This is the first report of D.hongkongensis causing diseases on blueberry.3.A species-specific PCR-based assay was developed for rapid and reliable identification of D.phaseolorum by designing a species-specific primer Pha5/6,by targeting ITS region of D.phaseolorum isolates.The PCR assay amplified 302 bp product from all the isolates of D.phaseolorum.The sensitivity of the assay was 500 fg when genomic DNA of D.paseolorum isolates was analysed.Designing a species-specific primer EFhongl/2,by EF1-?sequencedata of D.hongkongensis.The PCR assay amplified 195 bp product from all the isolates of D.hongkongensis.The sensitivity of the assay was 500 fg,the primers was also tested with DNA isolated from inoculated stems of blueberry.4.Ten cultivars of blueberry were selected to study their pathogenicity,with D.hongkongensis.D.phaseolorum.There were significant difference among the cultivars,and 2 spaces was different.For D.phaseolorum,stem canker lesions varied from about 1 mm in the most resistant cultivars to around 22.3 mm in susceptible varieties.'patriot','Reka','Sunrise','Olympia','Duke','Toro','Bluecrop'and 'Darrow'were the most resistant with average lesion lengths of 1.0 and 3.3 mm respectively.The cultivars 'Northland','Elliott' were the most susceptible with average lesion lengths between 20.0 and 22.3 mm.For D.hongkongensis,stem canker lesions varied from about 1.3 mm in the most resistant cultivars to around 134.6 mm in susceptible varieties.'patriot','Reka','Sunrise','Olympia','Duke','Toro','Bluecrop',were the most resistant with average lesion lengths of 1.0 and 16.0 mm respectively.The cultivars 'Northland','Elliott' and 'Darrow' were the most susceptible with average lesion lengths between 116.0 and 134.6 mm. |
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