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1.
The presence ofClavibacter michiganensis subsp.sepedonicus was detected by immunofluorescence and ELISA in diluent in which cores from 200 potato tubers had been incubated on a rotary shaker. By this procedure the ring rot pathogen was detected in composite samples from naturally infected tubers and tuber samples “spiked” with infected tissue or a pure culture of the pathogen. Populations of saprophytic bacteria increased about 100-fold in the diluent during 18 h of incubation but did not interfere with serological detection of C.m. sepedonicus. Some of the results suggest thatC. m. sepedonicus cells multiply during incubation of tuber samples. Extraction of ring rot bacteria from potato tuber tissue by incubation on a rotary shaker requires little work and minimizes the amount of plant tissue in the extract compared to the standard extraction procedure involving maceration and differential centrifugation.  相似文献   

2.
Summary An indirect sandwich enzyme-linked immunosorbent assay (ELISA) was used to monitor potato stems of three cultivars for the presence of the ring rot pathogen,Clavibacter michiganensis subsp.sepedonicus, during the growing season and in progeny tubers after harvest. The highest ELISA values were obtained with the highest concentration of bacteria used to inoculate seed pieces in all cultivars tested. Low ELISA values were obtained for stems and progeny tubers selected from plants grown from seed inoculated at lower bacterial concentrations. Estimates of bacterial densities in stems and progeny tubers by immunofluorescence indicated that low ELISA values were most probably caused by low bacterial numbers. It is suggested that the sensitivity of ELISA for detecting the ring rot pathogen in potato stems and progeny tubers is a function of the concentration of bacteria in individual seed pieces.  相似文献   

3.
Summary Plant-to-plant transmission of the bacterial ring rot (BRR) pathogen,Clavibacter michiganensis subsp.sepedonicus (Spieck. et Kott.) Skapt. et Burkh. of potato (Solanum tuberosum L.), was studied in field trials over a three year period. Healthy and infected seed tubers were planted 35 cm apart. In one treatment, a subsurface barrier was placed between the healthy and infected seed tubers separating the root systems of neighbouring plants. In this treatment, none of 216 plants grown from healthy seed tubers was infected at harvest, as determined by indirect immunofluorescence antibody staining (IFAS) with monoclonal antibodies. In the other treatment, no subsurface barrier was used. In this treatment, two of 368 plants (0.5%) grown from healthy seed tubers were infected at harvest. It is concluded that plant-to-plant transmission may occur but at very low frequency, and is unlikely to play a significant role compared with the potential of transmission by shared potato handling equipment.  相似文献   

4.
D. Stead 《Potato Research》1999,42(3-4):449-456
Summary The potato crop has several economically important bacterial pathogens including the soft rotErwinia spp., the brown rot pathogenRalstonia solanacearum, the ring rot pathogenClavibacter michiganensis subsp.sepedonicus and the scab formingStreptomyces spp. Their biology, control and diagnosis are discussed in relation to the micropropagation industry. Pathogen indexing of microplants and high grade seed potatoes e.g. mini-tubers, derived from them is likely to become increasingly important as a method of control of some if not all these pathogens.  相似文献   

5.
Summary Infection withClavibacter michiganensis subsp.sepedonicus reduced transpiration and xylem function in potato plants (Solanum tuberosum) prior to and during wilting. Transpiration depression and subsequent wilting of infected plants appears to result from reduced xylem function.  相似文献   

6.
Summary Potato stems and tubers grown in the field from seed tubers inoculated withClavibacter michiganensis subsp.sepedonicus, which causes bacterial ring rot, were tested by indirect, sandwich enzyme-linked immunosorbent assay (ELISA) in five laboratories. Correlation between values for each experimental treatment from the five laboratories was greater (r=0.86) than correlation between values for individual samples (r=0.71). When three or more laboratories obtained ELISA values of ≥0.200 for a sample, that sample was presumed to be positive. Conversely, when three or more laboratories obtained ELISA values <0.200, the consensus determination was regarded as negative. The percentage of stem and tuber samples that were in agreement with the consensus ELISA determination varied from 65.5 to 96.7%. Indirect immunofluorescence tests, conducted on the same samples in two laboratories, were consistent with 83.4–91.9% of the consensus ELISA determinations. Presence or absence ofC.m. sepedonicus was confirmed in some samples by an eggplant bioassay and direct isolatiion of the bacterium. The ELISA procedure was well suited for screening large numbers of samples and this study confirms it to be a promising procedure in routine indexing of seed potatoes forC.m. sepedonicus.  相似文献   

7.
Fungi of the genusFusarium Link isolated in Perú from potatoes (Solanum tuberosum L. subsp.andigena Juz. & Buk.) affected by: i) wilt, ii) dry rot of stored tubers, iii) secondary rot in tubers affected by “cork” disease (potato mop-top virus?), caused dry rot when inoculated to tubers of Renaacimiento variety. The identification of some of theseFusaria suggests thatFusarium solani Snyder & Hansen is associated with wilt and dry rot, andFusarium oxysporum Snyder & Hansen with rot secondary to cork disease. Tubers of eight potato varieties inoculated with fourFusaria representative of those isolated showed a great range in levels of susceptibility to colonization by theseFusaria, Sapa being the most susceptible variety, and Mantaro appearing to be the most resistant. These results suggest that useful levels of resistance toFusarium tuber rot are available in the Peruvian germ-plasm.  相似文献   

8.
Resistance to bacterial soft rot in potato tubers maintained aerobically was induced by wounding tubers 4 to 24 h prior to inoculation withErwinia carotovora subsp.carotovora. This wound-induced resistance phenomenon was blocked by hypoxic stress. An hypoxia-induced resistance mechanism also was detected: tubers acclimated to a hypoxic environment were resistant to rot when inoculated with aerobically grownE. c. subsp.carotovora and incubated in atmospheres made hypoxic by argon or nitrogen. With increased pretreatment, hypoxia-induced resistance approached the levels of resistance observed in tubers inoculated with aerobic-adapted bacteria and incubated aerobically. Hypoxia-adaptedE. c. subsp.carotovora overcame hypoxia-induced resistance.  相似文献   

9.
The aim of research was to evaluate an effect of weather conditions in the years of study considering the air temperature and precipitation as well as granulometric distribution of soil, taking into account the temperature and moisture content, on asymptomatic infection caused by Clavibacter michiganensis subsp. sepedonicus (Cms) in leaves and tubers. The level of infection of leaves and tubers with Cms was differentiated by the thermal and humidity conditions occurring in the years of research. The granulometric distribution of soil (soil profile) had a significant effect on the level of leaf infection. In the year 2014, with moderate temperature and humidity, the highest intensity of leaves and tubers infection was observed on soil of the highest moisture content – sandy loam. In the years with extreme weather conditions, i.e. the drought in 2015 or the abundant rainfall in 2016, the most intensive infection was observed in leaves and tubers grown on soil of low humidity – slightly loamy sand and loamy sand. The degree of infection was found to decrease with increasing air temperature and precipitation level as well as with the increase of soil moisture. On the other hand, increasing soil temperature favoured infection in tubers.  相似文献   

10.
Soft rot resistance in potato (Solanum tuberosum L.) tubers can be determined by inoculating tuber slices with soft rotErwinia species. Questions have been raised in the literature concerning the reliability of the tuber slice method. The objectives of this study were to 1) examine the statistical assumptions underlying the analysis of variance for different response variables as measures of soft rot resistance using the tuber slice method of evaluation; 2) estimate the sample sizes necessary to detect specified differences with power 0.83; and, 3) choose the “best” variable for measuring resistance to soft rot based on valid statistical analysis and minimal sample size. Slices from fifteen tubers from each of three cultivars (Atlantic, Norchip, Superior) were inoculated withErwinia carotovora subsp.atroseptica, E. carotovora subsp.carotovora orE. chrysanthemi and incubated at two different temperatures (20 C and 30 C) for 48 hrs. The test was conducted on two dates. Tuber samples were sliced and weighed prior to inoculation and after the macerated tissue was removed following a 48 hr incubation period. The maximum diameter of macerated tissue, actual weight loss, four measures of proportional weight loss, and various transformations of these variables were analyzed. The “best” response variables for measuring resistance to soft rot by the tuber slice method were the diameter of the macerated tissue and the square root transformation of one of the measures of proportional weight loss. No differences were found among the cultivars nor theErwinia subsp. for either of these response variables, and the cultivar ×Erwinia subsp., cultivar × temperature and cultivar ×Erwinia subsp. × temperature interactions were not significant. However, there were significant differences between the incubation temperatures, and theErwinia subsp. × temperature interaction was significant for both response variables. Estimates of sample sizes necessary to find a 20% difference in main effect and interaction effect means were calculated.  相似文献   

11.
Potato ring rot, caused by the bacterium Clavibacter michiganensis subspecies sepedonicus, is considered to be one of the internationally most important seed potato diseases (Smith et al.; Eur J Plant Pathol 107:739–748, 2001) and has been a problem in Norwegian potato production since its first detection in 1964. Since 1965, Norway has had its own national legislation for the control of the disease. In recent years, this legislation has evolved to be more similar to the EU Commission Directive 2006/56/EC. In 1999, the Norwegian Food Safety Authority initiated an eradication program for potato ring rot with the aim of selling potatoes to other European countries. During the project period (1999–2008), efficient systems for sampling, analysis and eradication measures were built. From 1999 to 2002, the occurrence of potato ring rot in commercial potato production was monitored in all counties. Sampling was carried out according to the instructions of the Norwegian Food Safety Authority, while testing of samples was (from 2000 onwards) carried out by Bioforsk laboratories with modern serological and molecular detection methods. When ring rot was detected in a potato lot, the grower had to implement strict eradication measures. The survey was followed up with two monitoring periods, 2003–2004 and 2005–2008. During the project period, 328 cases of potato ring rot were found. The counties Hedmark, Nordland, Troms, and Tr?ndelag accounted for most of these. The main objectives of this study were to describe the occurrence of potato ring rot in Norwegian potato production and to evaluate the effectiveness of the eradication measures employed for the control of the disease. This survey showed that the overall ring rot situation did improve considerably during the project period (1999–2008), both in relation to prior periods, and when comparing the surveying and monitoring periods. Problem areas where monitoring must be continued remain.  相似文献   

12.
A polymerase chain reaction (PCR)-based test for potato late blight (Phytophthora infestans) and pink rot (P.erythroseptica, P. nicotianae) diseases has been developed for use with potato tuber tissue. Primers based on sequence analysis of the ITS2 region of ribosomal DNA of late blight and pink rot pathogens were utilized in PCR assays of inoculated tubers and tubers harvested from plots known to have late blight and/or pink rot. Assays of artificially inoculated Kennebec and Russet Burbank tubers revealed thatP. infestans was detected by PCR as early as 72 h after inoculation and in the absence of visible symptoms. Much higher detection frequencies were obtained by PCR compared with plating on selective medium or placement of tissue in moist chambers. Tubers from plots known to have late blight and/or pink rot were tested using the PCR assay. Assay of late blight lesions showed ca. 80% recovery for late blight-infected tubers from the field. Results indicate that the PCR assay provides a rapid and accurate test for diagnosis of late blight and pink rot in potato tubers.  相似文献   

13.
The ring rot bacterium,Corynebacterium sepedonicum (Spieck. and Kotth.) Skapt. and Burkh. [Clavibacter michiganense subsp.sepedonicum (Spieck et Kotth.) Davis et al.], and latent potato viruses (potato virus S and potato virus X) were investigated for their effect on atypical (ATYP) ring rot symptom development on Russet Burbank potato plants at different temperatures. Plants grown at 21 C from stem cuttings root-inoculated withC. sepedonicum developed typical wilting and chlorotic symptoms of ring rot that were equally severe on virus-free (VF) and virus-infected (VI) plants. All VF and VI plants grown at 15 C from inoculated stem cuttings exhibited ATYP symptoms that included extreme stunting, resetting, and chlorotic symptoms of ring rot. More severe ATYP symptoms developed on VI than on VF plants. Up to 5 wk after inoculation withC. sepedonicum, ATYP symptom severity ratings of both VF and VI plants increased and declined thereafter. The ATYP severity ratings were highly correlated with fresh weight of plants with high severity ratings being associated with low fresh weights. These results emphasize the need to determine the role of temperature and viral pathogens on ring rot symptomology in existing and newly developed potato cultivars and thereby enable better field detection of bacterial ring rot.  相似文献   

14.
Infection of potato plants and tubers with the bacteriumErwinia carotovora subsp.atroseptica produces blackleg and soft rot diseases, which cause significant losses to crops and stored potatoes. In order to obtain resistance against this bacterium, the genechly encoding the enzyme lysozyme from chicken was introduced into potato plants (cv. Desirée) viaAgrobacterium- mediated transformation. Sixty-three and 69 transgenic potato clones were evaluated in the greenhouse for resistance to blackleg and soft rot diseases, respectively. Results reported in this paper indicate that 21%-29% of the potato clones showed increased resistance to infection by the bacteriumE. c. subsp.atroseptica T7, as revealed by a reduced severity of blackleg or soft rot symptoms. Nine clones showing different levels of resistance were selected for further molecular analysis. The number of copies of the transgene integrated in the plant genome of these clones was estimated by Southern blot analysis. The level of transgene expression, detected by Northern blot analysis, correlated with the level of resistance detected in these clones.  相似文献   

15.
The expression of foliar and tuber bacterial ring rot (BRR) symptoms in 108 cultivated potato genotypes inoculated withClavibacter michiganensis subsp.sepedonicum was examined in field experiments during 1986 to 1996. Considerable variation in the incidence of foliar BRR symptoms was observed in all plant cultivars, ranging from no detectable symptoms to complete necrosis of the leaves. Similar variability was observed in the incidence of tuber BRR symptoms, and severity of tuber symptoms ranged from no detected symptoms to complete breakdown of the vascular ring that extended throughout the tuber. A decline in the incidence and severity of tuber, but not foliar symptoms, was observed in the later years of the study (P<0.05). Foliar and tuber BRR symptoms generally were positively correlated (P<0.01) prior to 1993 but not in subsequent years (P>0.05) when tuber symptoms declined. Strong correlations were observed between the incidence and severity of foliar BRR symptoms (r=0.41, P<0.01) and between the incidence and severity of tuber BRR symptoms (r=0.96, P<0.001). During the 11 year period, no BRR symptoms were observed in 2,620 uninoculated control plants.  相似文献   

16.
Mechanically harvested tubers of 14 potato cultivars grown on both loamy sand and silt loam soils were evaluated for resistance to bacterial soft rot caused byErwinia carotovora subsp.atroseptica. Cultivars were also assayed for calcium and dry matter content to determine possible correlations with soft rot resistance. Resistance of potato tubers to bacterial soft rot was assayed after harvest by inoculating tubers and determining percent surface area decayed after four days in a mist chamber. Tubers of the cultivars differed widely in resistance to bacterial soft rot. The ranking of the resistance of tubers from different cultivars to bacterial soft rot was similar for both soils, although disease severity in tubers from a particular soil type varied with the season. Of the cultivars tested, tubers of Butte, Russet Burbank, and Nor-gold Russet were ranked as the most resistant, whereas tubers of Redsen, Norchip, Norland and Belchip were rated as the most susceptible. Tubers of Rhinered, Red La Soda, Superior, Pontiac, Atlantic, and Nooksack were intermediate in resistance. Neither calcium concentration in medullar tissues nor dry matter of potato tubers alone could be correlated with ranking of the cultivars with respect to severity of bacterial soft rot. However, a multiple linear regression model incorporating both variables indicated that tubers with a high content of both calcium and dry matter were likely to be less susceptible to bacterial soft rot than were tubers with lower percentages of these variables.  相似文献   

17.
The Quaggy Joe potato variety is high-yielding and medium to medium-late maturing with attractive, round-oval, white-skinned, white-fleshed tubers with medium-shallow pink eyes. Its major use is expected to be as a maincrop tablestock variety. Quaggy Joe is resistant to the potato leafroll virus, and is also moderately resistant to early blight (Alternaria solani), dry rot (Fusarium sambucinum), and soft rot (Erwinia carotovora subsp.carotovora). Quaggy Joe tubers have shown very little shatter or blackspot bruising, but sprout earlier than Atlantic. Young plants have shown sensitivity to the herbicide metribuzin.  相似文献   

18.
Corynebacterium sepedonicum was detected in symptomless potato stems and tubers with immunofluorescence using monoclonal antibodies specific for the bacterial ring rot pathogen. The concentration of bacterial cells in potato tissue preparations ranged from >500 cells/microscope field to 1 cell per preparation. Symptomless tubers containing ring rot bacteria planted in field plots yielded plants with ring rot symptoms, plants with latent ring rot infections, or plants with no detectable levels of ring rot bacteria. Tubers with the greatest number of bacteria were most likely to develop plants expressing ring rot symptoms, but even some seed tubers with a low number of bacteria developed into plants with symptoms. Some seed tubers with high levels of ring rot bacteria produced plants with only low numbers ofC. sepedonicum.  相似文献   

19.
Summary The efficiency of acetylsalicylic acid (ASA) in inducing localised acquired resistance against infection byErwinia carotovora subsp.carotovora was evaluated by treating potato tubers with ASA at three concentrations. Three days after treatments, tubers were inoculated withE. carotovora subsp.carotovora by wound inoculation or by irrigation with a bacterial suspension. Experiments were performed for two consecutive years. Statistical analysis revealed that treatment of tubers by immersion in ASA solutions at low concentrations induced a significant reduction in the soft rot incidence. Wounding of the tubers was the most effective inoculation method and ASA at concentration of 0.0125% (w/v), pH 7 was more efficient than at 0.025 or 0.05%. No phytotoxicity of such treatment was observed.  相似文献   

20.
马铃薯种薯中存在环腐病菌潜伏侵染,这种潜伏侵染逐代累积、逐渐表现症状,这是马铃薯环腐病无法根除的根本原因。本研究应用国外成功报道的根据存在于pCS1质粒和环腐菌染色体中一个1.3 kb的插入因子IS1121、高度重复的DNA片段设计的环腐病菌亚种特异性引物序列合成出引物对CMSIF1-CMSIR1和引物对CMSIF2-CMSIR2。以环腐标准菌株、黑龙江省环腐菌株以及马铃薯上其它主要的细菌病原菌(青枯病、软腐病、黑胫病)为试验材料进行直接PCR和嵌套式PCR扩增,结果只有环腐标准菌株和黑龙江省环腐菌株出现特异性片段(直接PCR扩增出1046 bp的片段,嵌套式PCR扩增出864 bp的片段)。将环腐菌纯菌种菌悬液稀释成浓度梯度并与马铃薯组织液混合进行直接PCR和嵌套式PCR检测灵敏度比较,结果表明嵌套式PCR检测灵敏度比直接PCR检测灵敏度提高了100￣1000倍。以明显感病症状的块茎、无明显感病症状的块茎和健康块茎为试验材料进行直接PCR和嵌套式PCR,结果除明显感病症状块茎外,所有无明显感病症状的块茎也均被检测出带有环腐病菌。  相似文献   

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