果树学报2017，Vol.34Issue(11)：1458-1466,9.DOI:10.13925/j.cnki.gsxb.20170085
烟台地区樱桃茎腐病病原菌、致病性及流行条件
Pathogens, pathogenicity and epidemic conditions of cherry stem rot in Yantai
摘要
Abstract
[Objective] Cherry stem rot,whose pathogen is Phytophthora nicotianae,represents a serious disease in the early stage of cherry seedlings.In these studies,we isolated and identified the pathogens found in the field to investigate the disease resistance of different cherry varieties and the conditions of the disease epidemic.These researches can provide scientific strategies for disease control and breeding.[Methods]The pathogen P1639 isolated from the cherry stem was collected from the field in the Fushan district of Yantai.The phenotypic characteristics (colony,mycelium,sporangium and chlamydospore morphology) of the pathogen were monitored by observation and using a microscope.We observed the morphology and color of the strain P1639 after being cultured on a PDA or 10％ V8 medium plate for 3 d.The morphology and size of the mycelium on the slide glass were observed and measured with a microscope.Morphology and sizes of chlamydospores and sporangium were observed and measured with the microscope after being induced and produced.The genomic DNA of the pathogen strain P1639 was extracted and then sequenced with ITS primers.The strain P1639 was inoculated on cherry leaves according to Koch's principle.A total of 17 different species (5 species and 1 intergeneric cross) of cherries were inoculated with P1639,and the pathogenicity was determined.P1639 was cultured on a solid plate of 10％ V8 for 4 d and then the new cherry stems were inoculated using plugs of 6 mm diameter from the plate after surface sterilization.The stems were made moist with absorbent cotton after inoculation,and cultured in an incubator with 25 ℃ 12 h light conditions.The results were statistically analyzed after 3 to 7 d.The pathogenicity of the strain P1639 to the leaves,the new stems and the woody stems of the cherry variety ‘ Van’ were further determined by laboratory tests.The leaves,new stems,and woody stems of the cherry variety ‘Van’ after surface sterilization were inoculated with plugs of 6 mm diameter from the plate.The leaves were moistened in Petri dishes with wet filter paper after inoculation.The stems were purified with absorbent cotton after inoculation.They were all cultured in the incubator with 25 ℃ 12 h light conditions.The results were statistically analyzed after 3 to 7 d.The occurrence of cherry stem rot in the cherry seedling field in Fushan district of Yantai was investigated for four years combining with local meteorological data (temperature,humidity and rainfall) and then we analyzed the epidemic dynamics and epidemic conditions of the disease.[Results]The colony of the pathogen Phytophthora nicotianae strain P1639 causing cherry stem rot disease showed a white color and irregular edges and the aerial hyphae was exuberant showing a slow growth on the PDA plate.The colony displayed a white color and regular edges and the aerial hyphae were exuberant showing a much faster growth on the 10％ V8 plate.Under the microscope,the hyphae were colorless and transparent,with a diameter of 2 to 6 μm;the sporangia (37.5-62.5 μm × 30-50 μm) were round or oval with obvious papillae;most of the chlamydospores (19-42 μm,average 30.4 μm) in the top or middle mycelium were round and a few were oval.The morphological and molecular identification showed that the strain P1639 was the cherry stem rot pathogen Phytophthora nicotianae.The pathogenicity of the isolated strain P1639 to 17 varieties of cherries was tested in the laboratory.The results showed that P1639 expressed different levels of pathogenicity to ‘ Wanfeng’ ‘ Mingzhu’ ‘ Lapins’ ‘ Tieton’ ‘Brooks’ ‘Summit’ ‘Santina’ ‘ Heizhenzhu’ ‘Hongdeng’ ‘Sunburst’ and ‘Van’.‘Wanfeng’ ‘ Mingzhu’ and ‘Lapins’ showed the strongest susceptibility with lesion length of 3.21 and 4.22 cm;‘Tieton’ and ‘ Brooks’ showed the second susceptibility with lesion length of 2.23 cm and 1.96 cm separately.‘ Summit’ ‘Santina’ ‘Heizhenzhu’ ‘Hongdeng’ ‘Sunburst’ and ‘Van’ showed lighter susceptibility with lesion lengths from 0.91 to 1.12 cm.The strains which showed no pathogenicity were ‘Daqingye’ ‘Mahaleb’ ‘Gisela 6’ ‘ZY-1’ ‘Dongbei flowering cherry’ and ‘Yingzhenwang’.The pathogenicity of the isolated strain P1639 to the leaves,new stems and woody stems of the cheery variety ‘Van’ was further determined in the laboratory.The results showed that P1639 could successfully infect the leaves and new stems,but could not infect the woody stems.According to the investigative results of 4 years,the cherry stem rot disease began in the middle of July,and ended in the middle of August,which had the highest average temperature (above 25 ℃) during the year.During the period of the middle to the end of July,if there was large rainfall and high humidity,the cherry stem rot disease would occur in a large outbreak,otherwise,the disease almost did not occur.[Conclusion]All these results indicate that the pathogen showed a strong pathogenicity to Prunus avium but no pathogenicity to P.pseudocerasus,P.Mahaleb,P.Serrulata,P.cerasus and ‘ZY-1 ’,an intergeneric cross between P.cerasus and P.canescens.The pathogen could successfully infect the leaves and new stems but not the woody stems of P.avium.The epidemic conditions of cherry stem rot were closely related to temperature,rainfall and relative humidity.Meanwhile,great outbreaks could appear in the rainy summer with the presence of high temperatures.关键词
樱桃茎腐病/烟草疫霉/樱桃品种/致病性/流行条件Key words
Cherry stem rot disease/Phytophthora nicotianae/Cherry cultivars/Pathogenicity/Epidemic conditions分类
农业科技引用本文复制引用
于晓丽,储昭辉,李宝燕,林霞,王培松,王英姿..烟台地区樱桃茎腐病病原菌、致病性及流行条件[J].果树学报,2017,34(11):1458-1466,9.基金项目
山东省中青年科学家科研奖励基金(BS2015NY004) （BS2015NY004）
农业部公益性行业专项(201303018) （201303018）
山东省现代农业产业技术体系果品产业创新团队病虫防治与质量控制岗位专家(SDAIT-06-11) （SDAIT-06-11）
