共查询到20条相似文献，搜索用时 31 毫秒
1.
Techniques based on nucleic acid amplification techniques, like PCR, are quick, sensitive and specific, and therefore very suitable for the development of diagnostic tests. These techniques enable the detection of very small amounts of target organisms by specific amplification of part of its genome. This exquisite sensitivity puts a high demand on measures to prevent false‐positive reactions due to contamination of the laboratory with nucleic acid, hence the need for inclusion of negative controls. In addition, to exclude false negatives, the performance of the reactions must be measured by the inclusion of several positive controls, e.g. cytochrome oxidase (COX) primers (and probes) to monitor efficiency of the nucleic acid extraction and an internal control to monitor inhibition of the target PCR. For the RT‐PCR assay for Potato spindle tuber pospiviroid (PSTVd) recently described by Boonham and coworkers, we have developed an exogenous internal standard, i.e. in vitro RNA transcribed from a plasmid containing a modified PSTVd sequence (a 17‐bp sequence of cloned PSTVd (isolate Howell) was substituted for a 118‐bp sequence of Escherichia coli). To this exogenous sequence, a specific probe was designed with a fluorescent label different from that of the PSTVd‐specific probe. By making use of the same primers as the target organism PSTVd, this internal standard provides a tool to measure the performance of the specific reaction. Moreover, by using another fluorescent probe, this standard can easily be discriminated from the target organism. The approach used for the construction of the internal control for PSTVd offers a tool for the construction of internal standards for other pathogens. 相似文献
2.
S. L. van Brunschot J. Th. J. Verhoeven D. M. Persley A. D. W. Geering A. Drenth J. E. Thomas 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(1):1-7
In 2011, an outbreak of the quarantine-regulated pathogen Potato spindle tuber viroid (PSTVd) occurred in a commercial glasshouse-grown tomato crop in Queensland, Australia. Phylogenetic studies showed that the genotype of this isolate grouped in a cluster of PSTVd genotypes from tomato and Physalis peruviana, and exhibited an interesting mutation (U257→A) that has previously been linked to lethal symptom expression in tomato. Transmission studies showed that the viroid could be mechanically transmitted from crushed fruit sap, but not from undamaged fruits. A low rate of asymptomatic infection was determined for plants in the affected glasshouse, demonstrating the efficacy of using symptoms to detect PSTVd infections in tomato. No PSTVd infections were detected in solanaceous weeds located outside of the infected glasshouse, excluding them from playing a role in the viroid epidemiology. Monitoring and subsequent testing of new tomato crops grown in the facility demonstrated successful eradication of the pathogen. A trace-back analysis linked the outbreak of PSTVd to an infected imported tomato seed-lot, indicating that PSTVd is transmitted internationally through contaminated seed. 相似文献
3.
Tomato plants infected with Potato spindle tuber viroid (PSTVd) had severe leaf curling and vein necrosis. The disease symptoms began to diminish during the late stages of infection, however, and almost healthy-looking leaves began to appear on the upper portion of the plants. PSTVd concentrations reached their highest levels in leaves with severe symptoms and decreased in upper leaves recovering from severe symptoms. PSTVd-specific short interfering RNAs (siRNAs), characteristic of RNA silencing, accumulated in all leaves in which PSTVd reached a detectable level, suggesting that recovery from severe disease was induced by RNA silencing via sequence-specific degradation of PSTVd. 相似文献
4.
J. Th. J. Verhoeven L. Hüner M. Virscek Marn I. Mavric Plesko J. W. Roenhorst 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(4):417-421
Potato spindle tuber viroid (PSTVd) has been recently found in many solanaceous ornamental plant species. This study reports on the effectiveness of
mechanical transmission between Brugmansia suaveolens, Solanum jasminoides, potato and tomato. Inoculation with ‘infected’ plant sap diluted in water, rubbing with contaminated finger tips and cutting
with contaminated razor blades all resulted in transmission of PSTVd. Temperature, plant species and source of inoculum were
found to be critical factors. An average temperature of 15°C only resulted in a few infections, whereas transmission at 20
and 25°C was more successful. Tomatoes were more susceptible to PSTVd than B. suaveolens, S. jasminoides and potatoes. Furthermore, S. jasminoides was a better source of inoculum than B. suaveolens. No transmission was obtained after repeated addition of inocula to tomato roots. These results indicate that PSTVd can be
transmitted between plant species in practice by crop handling. 相似文献
5.
Akiko Nakashima Munetaka Hosokawa Shigeichi Maeda Susumu Yazawa 《Journal of General Plant Pathology》2007,73(3):225-227
For the first time, Chrysanthemum stunt viroid (CSVd) was detected in commercial dahlia bulbs in Japan. CSVd was found in 77.2% of the tested plants (Dahlia spp.). In nucleotide sequence analysis, a CSVd variant was detected consisting of 354 nucleotides, which differed slightly
from previously reported CSVd variants.
The nucleotide sequence data reported is available in the DDBJ/EMBL/GenBank databases under accession number AB255879. 相似文献
6.
D. Bakker M. Bruinsma R.W. Dekter M.A.J. Toonen J. Th. J. Verhoeven H.M.S. Koenraadt 《EPPO Bulletin》2015,45(1):14-21
Worldwide outbreaks of pospiviroids in potato and tomato have increased the need for a reliable test for the detection of pospiviroids in seeds. This study describes the development and validation of a sensitive and fast test for the detection of Potato spindle tuber viroid (PSTVd) and Tomato chlorotic dwarf viroid (TCDVd) in tomato seeds. The test is based on RNA isolation using a commercial kit and is suitable for routine application. The test is able to detect one PSTVd or TCDVd contaminated seed in sub samples of 1000 seeds and results were both repeatable and reproducible. 相似文献
7.
Yosuke Matsushita Tomio Usugi Shinya Tsuda 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(4):441-447
In situ hybridization was used to analyze the distribution pattern of Tomato chlorotic dwarf viroid (TCDVd) in floral organs of tomato plants. Following TCDVd invasion of floral organs, it became localized only in sepals
at an early developmental stage, then reached other floral organs at the flower opening stage, with the exception of part
of the placenta and ovules. When distribution of TCDVd was compared with that of Potato spindle tuber viroid (PSTVd), TCDVd was not detected in the outer integument around the embryo sac even though PSTVd was able to invade there,
suggesting that such specific distribution might reflect the frequent occurrence of viroid disease on crops caused by PSTVd-seed
transmission. 相似文献
8.
9.
Rudra P. Singh Andrea D. Dilworth Xiaoping Ao Mathuresh Singh Santosh Misra 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(1):63-72
Tomato chlorotic dwarf viroid (TCDVd) manually inoculated to transgenic (cv.‘Desiree’) potato plants containing antimicrobial cationic peptides failed
to develop symptoms in above ground plant parts, but infected tubers were symptomatic. Plants from the infected tubers (second
generation plants) emerged as either severely stunted (bushy stunt isolate, BSI) or tall and symptomless. Molecular characterization
of BSI isolates showed TCDVd sequence variants 95 to 98% identical to TCDVd sequences from the database, while a viroid variant
identical to TCDVd type isolate (acc # AF162131) was cloned from symptomless plants. The TCDVd BSI variants had novel U165C,
GU177-178AA, and UCAC181-184CUUU nucleotide substitutions in the terminal right (TR) domain of the viroid molecule. The cloned viroid cDNAs of the BSI were infectious to experimental (cv. ‘Sheyenne’) tomato
plants causing stunted plants with profuse auxiliary shoots. Visual evaluation of the susceptibility of the BSI to 18 potato
and 21 tomato cultivars revealed severe symptoms in most cultivars of both species. The progeny variants accumulating in each
potato and tomato cultivar exhibited the same novel TR domain in most cultivars, with only a slight variation in a few. The severity of the stunting symptoms induced by TCDVd from
BSI isolates in both potato and tomato cultivars has not been noted previously with other TCDVd isolates and, as such, it
is proposed that this new isolate be recognized as a distinct genotype. Emergence of this type of sequence variant in commercial
fields or commercial tomato greenhouses could potentially cause relevant losses in both crops. 相似文献
10.
Selected wild Dahlia species in their natural habitats from west‐central Mexico were tested for the presence of three caulimoviruses known to be associated with cultivated dahlia (Dahlia variabilis), viz. Dahlia mosaic virus (DMV), DMV‐D10 and Dahlia common mosaic virus. Virus species‐specific primers and PCR were used followed by cloning and sequencing of the amplicons. Results showed that the wild dahlia species in their natural habitat contained DMV‐D10, which is an endogenous plant pararetrovirus. Viral sequences were found in 91% of the samples (n = 56) representing four different wild species. The gene coding for the movement protein of DMV‐D10 from Dahlia coccinea and all other species was cloned and sequenced. Sequence comparisons showed divergence of this gene when compared to that of DMV‐D10 from cultivated dahlias. The discovery of plant pararetroviruses in wild dahlia species in their natural habitats suggests a possible emergence, co‐existence and co‐evolution of pararetroviruses and their host plants. 相似文献
11.
12.
J. W. Roenhorst C. C. C. Jansen L. F. F. Kox E. G. De Haan G. W. Van Den Bovenkamp N. Boonham T. Fisher R. A. Mumford 《EPPO Bulletin》2005,35(1):133-140
The real‐time RT‐PCR protocol of Boonham and coworkers performed extremely well in a recent ring test, comparing different methods for detection of Potato spindle tuber pospiviroid (PSTVd) in several laboratories. Since, in addition, real‐time PCR technology has proved suitable for high‐throughput testing, this method was chosen as the starting point for the development of a protocol for the large‐scale testing of potato. The initial experiments focused on the specificity of the primers and probes with regard to different isolates of PSTVd and other (pospi‐) viroids. Further experiments were performed with leaf material from both primarily and secondarily infected plants. The parameters studied were sampling position, growing‐on temperature and bulking rate. In addition, different grinding, nucleic‐acid extraction and disinfection methods were compared. To monitor false negatives and positives, different controls were included and tested in duplex and triplex formats. The final protocol was tested using a hundred samples from the Dutch potato‐monitoring programme. The results of this pilot experiment were promising. Future plans include the development of a protocol for direct tuber testing and inter‐laboratory ring testing of the protocols. 相似文献
13.
北京引致大丽菊花叶症的三种病毒 总被引：2，自引：0，他引：2
大丽菊(Dahlia pinnata Cav.)花叶病已成为花卉生产出口的严重障碍。作者于1986-1987年在表现花叶的北京大丽菊上分离到两种形态大小不同的病毒分离物,电镜检测到一直径较大的球形病毒,分别定为BDM-1、BDM-2和BDM-3。经寄主反应、体外抗性、粒体形态、血清学等鉴定,病毒分离物BDM-1是黄瓜花叶病毒CMV;BDM-2是烟草花叶病毒TMV;BDM-3是大丽菊花叶病毒DaMV。从寄主反应、粒体大小、衣壳蛋白氨基酸组份及沉降特性综合分析看,BDM-1可能是CMV的另一株系CMV-DP。 相似文献
14.
Nadia Bertazzon Michele Borgo Stefano Vanin Elisa Angelini 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):185-197
The genetic variability among Grapevine leafroll-associated virus 2 (GLRaV-2) isolates was investigated in several grapevine accessions from various geographic origins in three genomic fragments,
which encode the 70 kDa heat-shock protein homologue, the coat protein and the ∼60 kDa protein. The majority of the isolates
were identical or only slightly different from one another and formed a monophyletic group. Several other variants were found
which differed greatly from the main cluster and were mostly present in autochthonous or specific vine cultivars. Phylogenetic
analyses on the CP gene sequences, including the isolates analyzed in this work and some others from related literature, allowed
five clades to be identified (PN, H4, RG, BD and PV20). Biological trials for graft incompatibility and leafroll symptoms
revealed that GLRaV-2 divergent variants had different pathological properties, mainly according to their phylogenetic grouping.
The BD isolate seemed to be a mild variant of the virus, because it was unable to induce graft incompatibility and it rarely
caused leafroll symptoms. The RG isolate appeared to be a more virulent variant, given the strong decrease in rooted grafted
grapevines obtained in nursery, in particular with the use of certain rootstocks; however, it does not induce leafroll symptoms.
The variants belonging to the PN group, which were the most widespread, caused both graft incompatibility and leafroll symptoms,
according to the viral variant. Graft incompatibility also proved to depend strongly on the rootstock used. 相似文献
15.
In autumn 2006 in the Netherlands, Potato spindle tuber viroid (PSTVd) infections were detected in 42·3 and 71·9% of professionally grown lots of Brugmansia spp. and Solanum jasminoides respectively. The infected lots contained 73 985 and 431 374 plants, respectively, demonstrating the presence of many potential viroid sources for tomato ( Solanum lycopersicum ). PSTVd was identified in cultivars of Brugmansia × candida , B. × flava , B. sanguinea , B. suaveolens and unspecified Brugmansia species/cultivars. Most infected lots of Brugmansia spp. originated from a single Dutch nursery; most infected lots of S. jasminoides originated abroad. Sequence analysis revealed that the PSTVd genomes from Brugmansia spp. contained an average of 360 nt, whereas all genomes from S. jasminoides except one consisted of 357 nt. Furthermore, the collective PSTVd genotypes showed polymorphism at four or more positions, except for two cases in which genotypes from Brugmansia spp. and S. jasminoides were identical. Phylogenetic studies showed that PSTVd genotypes from Brugmansia spp. and S. jasminoides grouped apart from each other and from PSTVd isolates from potato ( Solanum tuberosum ) and Physalis peruviana . The PSTVd genotypes from tomato did not form a separate cluster, but were dispersed over clusters of vegetatively or partly vegetatively propagated plant species, i.e. potato, P. peruviana and S. jasminoides . Moreover, mechanical inoculation of the predominant PSTVd genotypes from S. jasminoides to tomato was successful. These results provide evidence that vegetatively propagated, solanaceous plant species have been sources of infection for tomato crops in the past. 相似文献
16.
Hanna Berniak Maria Kamińska Tadeusz Malinowski 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(3):305-309
Four cucumber mosaic virus isolates (named Cas, CB, P26 and Simp2) found in naturally infected lily plants were characterized
on the basis of their serological properties and the results of analysis of RNA3 sequence fragments containing coat protein
and movement protein genes. The properties of lily isolates were compared with those of eight other virus isolates originating
from dahlia, delphinium, impatiens, honeysuckle, cucumber and redcurrant plants. On the basis of the reaction with group-specific
monoclonal antibodies and RNA3 sequence analysis, two lily isolates (Cas and CB) were classified to group I of CMV, similarly
to all previously reported virus isolates found in lily plants. Surprisingly, sequences of coat protein and movement protein
genes of two other lily isolates (P26 and Simp2) showed more than 98% similarity to CMV group II isolates, and only 77% similarity
to group I isolates. Results of ELISA with CMV group II-specific monoclonal antibodies confirmed the classification of isolate
Simp2 as a member of group II. Isolate P26 reacted neither with CMV group I nor with group II-specific monoclonal antibodies.
In order to explain the lack of reaction of P26 isolate with monoclonal antibodies, comparative analysis of predicted amino
acid sequence of the coat protein was done. This revealed a mutation—change from alanine at position 138 to threonine, probably
responsible for particular serological properties of isolate P26. 相似文献
17.
18.
19.
Florian Chain Gérard Riault Maxime Trottet Emmanuel Jacquot 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):35-43
Serial passage experiments (SPE) of a Barley yellow dwarf virus-PAV (BYDV-PAV) isolate were performed on Zhong ZH and TC14 wheat lines to evaluate the durability of their resistance to BYDV. At different passage numbers (from the 2nd to the 114th), biological properties of the produced isolates were recorded either by monitoring infection percentages and virus titers of the first 3 weeks of viral infection or by measuring their impact on yield components. Statistical analyses using the area under pathogen progress curves and the area under concentration progress curves demonstrated that these two resistant lines induce, after only a few passages, a selection of variant(s) with significantly modified infection abilities. Isolates resulting from SPE performed on these lines induced important decreases of yield components. These results indicate that the use of Zhong ZH and TC14 lines in BYDV-resistant breeding programmes should be approached with caution. 相似文献
20.
Composting to sanitize plant‐based waste infected with organisms of plant health importance 
下载免费PDF全文
下载免费PDF全文 G. Kerins J. Blackburn T. Nixon M. Daly C. Conyers S. Pietravalle R. Noble C. M. Henry 《Plant pathology》2018,67(2):411-417
The potential for using the composting process to sanitize plant waste infected with one of three plant pathogens was investigated using bench‐scale composting equipment. Two of these pathogens, the potato wart disease fungus Synchytrium endobioticum and Potato spindle tuber viroid (PSTVd) are currently subject to European quarantine regulations. The third, Polymyxa betae, a parasite of sugar beet, is regulated in some European countries when in association with Beet necrotic yellow vein virus (BNYVV), the causal organism of rhizomania disease of sugar beet. Survival of test organisms following various combinations of compost temperature, exposure time and moisture was determined using RNA‐based detection methodology and/or plant‐based bioassays. Mathematically definable relationships between compost treatment (temperature/time) and organism viability were identified for P. betae and S. endobioticum; these give some indication of the practicality of using composting for dealing with infected wastes. However, for PSTVd, the considerable variability in measured susceptibility of the viroid to the composting process meant that no such definable relationship could be determined and further work would be needed to extrapolate to practical situations. 相似文献