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1.
Development of a real‐time PCR method for the detection of the dagger nematodes Xiphinema index,X. diversicaudatum,X. vuittenezi and X. italiae,and for the quantification of X. index numbers 下载免费PDF全文
The ectoparasitic dagger nematodes Xiphinema index and Xiphinema diversicaudatum, often at low numbers in the soil, are vectors of grapevine nepoviruses, which cause huge agronomical problems for the vineyard industry. This study reports a method, based on real‐time PCR, for the specific detection of these species and of the closely related non‐vector species Xiphinema vuittenezi and Xiphinema italiae. Specific primers and TaqMan probes were designed from the ribosomal DNA internal transcribed spacer 1 (ITS1), enabling the specific detection of single individuals of each of the X. index, X. diversicaudatum, X. italiae and X. vuittenezi species whatever the nematode population. The specificity of detection and absence of false positive reaction were confirmed in samples of each species mixed with the three other Xiphinema species or mixed with nematodes representative from other genera (non‐plant‐parasitic Dorylaimida, Longidorus sp., Meloidogyne spp., Globodera spp. and Pratylenchus sp.). The method was shown to be valid for the relative quantification of X. index numbers through its use, from crude nematode extracts of soil samples, in a greenhouse assay of grapevine accessions ranging from highly susceptible to resistant. As an alternative to time‐consuming microscopic identification and counting, this real‐time PCR method will provide a fast, sensitive and reliable diagnostic and relative quantification technique for X. index nematodes extracted from fields or controlled conditions. 相似文献
2.
Shesh Kumari Wilfrida Decraemer Francesca De Luca Wolfgang Tiefenbrunner 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(4):493-499
Genetic analyses using sequences of partial cytochrome c oxidase subunit 1 (cox1) gene of mitochondrial DNA were conducted to determine the extent of genetic variation within and among Xiphinema diversicaudatum, X. pachtaicum, X. simile and X. vuittenezi populations. Pairwise distance among the four species was 22.5 to 31.2%. Four different sequence variants of cox1 were determined among six populations of X. diversicaudatum and three variants among three populations of X. simile. Nucleotide variation was detected at 18 of 414 bp (1.9 to 2.7%) in X. diversicaudatum and 4 of 435 bp (0.2 to 0.9%) in X. simile. All changes were at silent sites. No nucleotide variation was detected within three populations of X. pachtaicum and within three populations of X. vuittenezi. 相似文献
3.
S.V. Tsygankova A.N. Ignatov E.S. Boulygina B.B. Kuznetsov E.V. Korotkov 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):845-853
Novel primers for rep-PCR were developed with the original software and based on `ancient diverged periodical sequences'. Rep-PCR with these primers was applied to study genetic relationships among 51 Xanthomonas campestris strains. The strains were collected from different countries including Russia, Japan, UK, Germany and Hungary. Reference strains of three X. campestrispathovars and five other Xanthomonas species were included. Based on qualitative differences in amplification profiles, the strains were divided into four major groups. Two subgroups recognised within X. campestrispopulation were similar to RFLP haplotypes. The third subgroup included strains of two other pathovariants and Japanese isolates of X. campestris pv. campestriswhile the fourth group comprised the other species of Xanthomonas. The analysis of the diversity within X. campestris resulted in the conclusion that isolates belong to distinct clonal populations (subgroups). The differences between the subgroups of X. campestris were only slightly smaller than between species of Xanthomonas. A PCR fragment about 600 bp amplified by primer KRPN2 was found in nearly all tested strains of X. campestris.SCAR primers designed for this marker produced a single specific band for strains of X. campestris, but not for other Xanthomonas, Pseudomonas and Erwiniastrains tested. Application of the new primer set for rep-PCR offers a rapid, simple and reproducible method for identification of bacterial strains. The X. campestris-specific SCAR primers may be used in diagnostics of this important plant pathogen. 相似文献
4.
Rachidatou Sikirou Kerstin Wydra 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(9):939-947
The survival of Xanthomonas axonopodis pv. vignicola, incitant of cowpea bacterial blight and pustule, in residues of infested cowpea leaves was studied in the field in the forest savanna transition zone of South Benin and under variable controlled conditions. The pathogen survived for up to 60 days when placed on the soil surface, and up to 45 days buried at depths of 10 and 20 cm. In the glasshouse, bacteria survived in residue mixed with soil for at least 2 months in dry soil and less than 2 months in moist soil. The pathogen survived at least 30 days in the field after spray-inoculation on the weed species Euphorbia heterophylla, Digitaria horizontalis and Synedrella nodiflora; 20 days on Panicum subalbidum; 10 days on Euphorbia
hirta; and 5 days on Talinum triangulare. After leaf-infiltration under glasshouse conditions, the pathogen was detected after 90 days in D. horizontalis; 75 days in T.
triangulare, P. subalbidum and S. nodiflora; 60 days in E. hirta, and 30 days in E. heterophylla. Among 12 legume species tested as alternative hosts of X. axonopodis pv. vignicola, only Sphenostylis stenocarpa (African yam bean) showed typical symptoms of cowpea bacterial blight in a glasshouse experiment following artificial inoculation. This is the first time this legume species has been identified as a potential host of X. axonopodis pv.vignicola. Crop residue and weeds are likely sources of primary inoculum when planting two consecutive cowpea crops per year and they probably play a role in dissemination of the pathogen during the cropping season. The alternate host may form a bridge for primary inoculum between cropping seasons. 相似文献
5.
Judith Hübschen Lilo Kling Ulrike Ipach Volker Zinkernagel Derek Brown Roy Neilson 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(9):883-891
The nematode species Longidorus attenuatus, L. elongatus, L. macrosoma and Paralongidorus maximusare economically important pests to the viticulture industry due to their ability to vector two nepoviruses (Raspberry Ringspot Virus and Tomato Black Ring Virus) to grapevines. In Germany, these species occur in vineyard soil with other non-vector but morphologically similar longidorid species, L. helveticus, L.profundorum and L. sturhani. Species-specific primers were designed from ribosomal DNA for all seven species to facilitate taxonomic identification for non-specialists. Primers were assessed for their reliability by screening, where possible, a number of populations of each species. Furthermore, their selectivity and sensitivity were determined when challenged with closely related longidorid species and general nematode communities typical of vineyard soil. A multiplex approach using a common forward primer combined with species-specific reverse primers enabled three target nematode species to be detected in the same PCR reaction. All primers were highly specific, detecting all nematode developmental forms from disparate populations and were sufficiently sensitive to detect a single target nematode within a whole nematode community typical of a vineyard soil comprising of a range of non-target species. Given their specificity, sensitivity and reliability, these diagnostic primers should be of great benefit to both phytosanitary/quarantine services related to the viticulture industry and also as a decision management tool for growers. 相似文献
6.
Kim D. Bowman Ute Albrecht James H. Graham Diane B. Bright 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(2):143-158
Phytophthora nicotianae and P. palmivora are the most important soil-borne pathogens of citrus in Florida. These two species were detected and identified in singly
and doubly infected plants using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of internal
transcribed spacer (ITS) regions of ribosomal DNA. The sensitivity of the PCR-RFLP was analyzed and the usefulness of the
method evaluated as an alternative or supplement to serological methods and recovery on semi-selective medium. In a semi-nested
PCR with universal primers ITS4 and ITS6, the detection limit was 1 fg of fungal DNA, which made it 1000× more sensitive than
a single-step PCR with primers ITS4 and DC6. The sensitivity of detection for P. nicotianae was shown to be ten-fold lower than for P. palmivora, limiting its detection with restriction profiles in plants infected by both fungal species. Phytophthora nicotianae was detected with species-specific primers in all samples inoculated with this species despite the absence of species-specific
patterns in RFLP. In contrast, the incidence of detection of P. palmivora in the presence of P. nicotianae was considerably lower using plating and morphological detection methods. Due to its high sensitivity, PCR amplification
of ribosomal ITS regions is a valuable tool for detecting and identifying Phytophthora spp. in citrus roots, provided a thorough knowledge of reaction conditions for the target species is established prior to
the interpretation of data. 相似文献
7.
Antonio Ippolito Leonardo Schena Franco Nigro Vincenza Soleti ligorio Thaer Yaseen 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):833-843
Two primers, specific for Phytophthora nicotianae (Pn6) and P. citrophthora (Pc2B), were modified to obtain Scorpion primers for real-time identification and detection of both pathogens in citrus nursery soils and roots. Multiplex PCR with dual-labelled fluorogenic probes allowed concurrent identification of both species ofPhytophthora among 150 fungal isolates, including 14 species of Phytophthora. Using P. nicotianaespecific primers a delayed and lower fluorescence increase was also obtained from P. cactorumDNA. However, in separate real-time amplifications, the aspecific increase of fluorescence from P. cactorum was avoided by increasing the annealing temperature. In multiplex PCR, with a series of 10-fold DNA dilutions, the detection limit was 10 pg l-1 for P. nicotianaeand 100 pg l–1 for P. citrophthora, whereas in separate reaction DNA up to 1 pg l-1 was detected for both pathogens.Simple and rapid procedures for direct DNA extraction from soil and roots were utilised to yield DNA whose purity and quality was suitable for PCR assays. By combining these protocols with a double amplification (nested Scorpion-PCR) using primers Ph2-ITS4 amplifying DNA from the main Phytophthora species (first round) and PnB5-Pn6 Scorpion and Pc2B Scorpion-Pc7 (second round), it was possible to achieve real-time detection of P. nicotianaeand P. citrophthora from roots and soil. The degree of sensitivity was similar to that of traditional detection methods based on the use of selective media. The analyses of artificially and naturally infested soil showed a high and significant correlation between the concentration of pathogen propagules and the real-time PCR cycle threshold. 相似文献
8.
Federica Bini Klaus Geider Carlo Bazzi 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(3):403-411
Tumour tissue samples were collected from vines grown in various regions of Italy and other parts of Europe and extracted
for detection of Agrobacterium vitis. Fifty strains were isolated on agar plates and screened by PCR with consensus primers from the virD2 gene. They were confirmed as A. vitis with a species-specific monoclonal antibody. The isolates were further analyzed by PCR for their opine synthase genes and
ordered into octopine, nopaline and vitopine strains. Primers designed on the octopine synthase gene did not detect octopine
strains of Agrobacterium tumefaciens. For quantitative PCR, virD2 fragments were sequenced: two classes of virD2 genes were found and two primer sets designed, which detected octopine and nopaline strains or only vitopine strains. For
simultaneous identification of all opine-type strains, multiplex real-time PCR with either primer pair and SYBR Green was
performed: the combined sets of primers gave signals with DNA from any A. vitis strain. Specificity of the new primers for real-time PCR was evaluated using several unidentified bacterial isolates from
grapevines and other plant species. An elevated level of non-specific background was observed when the combined primer sets
were used in multiplex PCR assays. The real-time PCR protocol was also used to detect A. vitis cells directly from grapevine tumours; avoiding direct isolation procedures a sensitivity in the range of one to ten cells
per assay was found. Inhibition of the PCR reaction by plant material was overcome by treating tumour extracts with a DNA
purification kit as a step for the isolation of nucleic acids. 相似文献
9.
Massimo Zaccardelli Francesco Campanile Annalisa Spasiano Massimo Merighi 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):299-306
The development of a rapid detection method for Xanthomonas campestris pv. campestris (Xcc) in crucifer seeds and plants is essential for high-throughput certification purposes. Here we describe a diagnostic
protocol for the identification/detection of Xcc by PCR amplification of fragments from the pathogenicity-associated gene
hrcC. Under stringent conditions of amplification, a PCR product of 519 bp from hrcC was obtained from a collection of 46 isolates of Xcc, with the exception of two isolates from radish. No amplicons were obtained
from 39 pure cultures of the phytopathogenic bacteria Xanthomonas campestris pv. cerealicola, X. campestris pv. juglandis, X. campestris pv. pelargonii, X. campestris pv. vitians, X. arboricola pv. pruni,
X. axonopodis pv. phaseoli, X. axonopodis pv. vesicatoria, X. vesicatoria, Pseudomonas syringae pv. phaseolicola, P. syringae pv. syringae, P. syringae pv. tomato, P. fluorescens, P. marginalis, Pectobacterium atrosepticum, P. carotovorum subsp. carotovorum. In addition, PCR reactions were negative for fifty unidentified environmental isolates purified from the surface of crucifers.
The PCR fragment was obtained from four strains previously classified as X. campestris pv. aberrans, X. campestris pv. armorociae, X. campestris pv. barbarae and X. campestris pv. incanae using pathogenicity assays. Our PCR protocol specifically detected Xcc in inoculated leaves, seeds and naturally infected
leaves of crucifers. 相似文献
10.
Kerstin Wydra Gopal Khatri-chhetri Athanassios Mavridis Rachidatou Sikirou Klaus Rudolph 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(10):991-1001
A semi-selective medium for isolation of Xanthomonas axonopodis pv. vignicola from cowpea (Vigna unguiculata) plant and soil samples was developed. Twelve carbon and five nitrogen sources were tested with four strains of X. axonopodispv.vignicola, and 25 antibiotics were screened against saprophytes. -cellobiose (10g) was selected as the optimal carbon source. Among the antibiotics, cefazoline inhibited growth of most of the saprophytes with little effect on strains of the pathogen. ,-methionine enhanced growth of X. axonopodispv.vignicola. Boric acid along with ammonium chloride suppressed growth of Pseudomonas fluorescens. The semi-selective medium designated as cefazoline-cellobiose-methionine (CCM) medium contained K2HPO4 1.34g, KH2PO4 0.4g, MgSO4 0.3g, H3BO3 0.2g, NH4Cl 1.0g, -cellobiose 10g, cycloheximide 0.2g, ,-methionine 1.0g, cefazoline 10mg and agar 14g per l of water (pH 7.2). Colonies of X. axonopodispv.vignicola on CCM medium were whitish, round, raised and 0.2–1.8mm in diameter 96h after incubation. CCM medium generally inhibited growth of Pantoea agglomerans, Bacillus subtilis and saprophytes isolated from cowpea leaves. Colonies of Pseudomonas fluorescens and a saprophytic bacterium, which were not completely suppressed by CCM, could be differentiated from X. axonopodispv.vignicola by their smaller size and different color. The CCM medium proved useful for isolation of X. axonopodispv.vignicola from cowpea plant and soil samples. This is the first report of a semi-selective medium developed for detection of X. axonopodispv.vignicola. 相似文献
11.
Hedvig Komjáti Ilona Walcz Ferenc Virányi Reinhard Zipper Marco Thines Otmar Spring 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(4):421-428
Leaves of Xanthium strumarium infected with downy mildew were collected in the vicinity of a sunflower field in southern Hungary in 2003. Based on phenotypic
characteristics of sporangiophores, sporangia and oospores as well as host preference the pathogen was classified as Plasmopara angustiterminalis. Additional phenotypic characters were investigated such as the size of sporangia, the number of zoospores per sporangium
and the time-course of their release. Infection studies revealed infectivity of the P. angustiterminalis isolate to both X. strumarium and Helianthus annuus. Inoculation of the sunflower inbred line, HA-335 with resistance to all known P. halstedii pathotypes, resulted in profuse sporulation on cotyledons and formation of oospores in the bases of hypocotyls. Infections
of sunflower differential lines often led to damping-off. Molecular genetic analysis using simple sequence repeat primers
and nuclear rDNA sequences revealed clear differences to Plasmopara halstedii, the downy mildew pathogen of sunflower. 相似文献
12.
Mohamed Kerkoud Magali Esquibet Olivier Plantard Myriam Avrillon Corinne Guimier Martine Franck Joël Léchappé Rene Mathis 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):323-332
A technique based on the use of specific primers for polymerase chain reaction (PCR) was developed for the identification
of the stem and bulb nematode belonging to the Ditylenchus dipsaci species complex. The internal transcribed spacer region ITS1 and ITS2, the gene 5.8 S and part of genes 18 S and 26 S of
twenty populations of the D. dipsaci species complex belonging to both D. dipsaci sensu stricto and Ditylenchus sp. B (corresponding to populations of giant individuals associated to Vicia faba) and three congeneric species were amplified with two universal ribosomal primers. PCR-amplified DNA samples were digested
with five restriction enzymes in order to reveal some polymorphism allowing the identification of D. dipsaci populations associated with Fabaceae seeds. The polymorphism among species was confirmed by the sequencing of the PCR products.
A primer (DdpS2) was designed in a region conserved in all populations of both D. dipsaci
sensu stricto and D. sp. B studied in the present work. The other Anguinidae species (except a few species from Central Asia associated to Astereaceae
and D. sp. G associated to Plantago maritima) differ in two to four nucleotides at the 3′ extremity of this region. This sequence portion coincides with a TspEI restriction site. In combination with a primer located in the ribosomal region, this first primer is a good candidate for
identification by PCR of populations of the D. dipsaci species complex found in Fabaceae seeds. A second primer (DdpS1) was designed in a similar way and was specific to D. dipsaci sensu stricto. The utility of these two sets of primers is discussed against the background of quarantine regulation. 相似文献
13.
Shesh Kumari Wilfrida Decraemer Donato Traversa Marta Lišková 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(2):125-137
The plant–parasitic nematode Longidorus poessneckensis from the Czech Republic was morphologically and molecularly characterised. Molecular analyses were carried out using mitochondrial
DNA (cytochrome c oxidase subunit 1—cox1) and ribosomal DNA (ITS2—second internal transcribed spacer, 18S gene and D2/D3 expansion segments of the 28S gene), which
were amplified and sequenced. Phylogenetic relationship of L. poessneckensis with three morphologically closely related species, i.e. L. macrosoma, L. helveticus and L. uroshis, was inferred by using maximum likelihood and maximum parsimony methods, with a female of Xiphinema diversicaudatum and a bivulval female of X. vuittenezi as outgroups. All multiple alignments yielded similar basic trees supporting the uniqueness of L. poessneckensis and the validity of the four Longidorus species identified using morphological characters. Phylogenetic analyses revealed that L. poessneckensis is more closely related to L. macrosoma and L. helveticus than to L. uroshis. High inter-population diversity (19%) was observed across the cox1 gene between two populations of L. poessneckensis. 相似文献
14.
Joana M. S. Cardoso Luís Fonseca Isabel Abrantes 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(2):419-425
The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. The international economic impact of the introduction of the PWN into new areas
has highlighted the need for the development of accurate and reliable detection methods of B. xylophilus, which are essential to define aspects of its control and management. In the present study, a methodology was developed for
the direct detection of PWN by conventional PCR assay, with a species specific set of primers based on PWN satellite DNA,
using total DNA extracted directly from maritime pine, Pinus pinaster, wood and bark samples, and from the insect vector, Monochamus galloprovincialis. This methodology involves homogenisation of wood, bark and insects using liquid nitrogen, DNA extraction and one or two
PCR amplification steps, which permit the rapid and direct detection of one single nematode present in 100 mg of wood and
bark and in one entire insect without the preliminary steps of nematode extraction. 相似文献
15.
Leena Tripathi Jaindra Nath Tripathi Wilberforce Kateera Tushemereirwe Ranajit Bandyopadhyay 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(2):177-186
Banana Xanthomonas wilt, caused by Xanthomonas campestris pv. musacearum, is a new threat to banana cultivation in eastern Africa. The causal bacterium grows slowly in culture and is easily overgrown
by contaminants. A selective culture medium for isolation of X. c. pv. musacearum will facilitate disease study. A medium that suppressed saprophytic growth and possessed diagnostic characters for the pathogen
was developed. Various carbon sources were tested with two isolates of X. c. pv. musacearum, and sucrose was selected as main carbon source. The susceptibility of X. c. pv. musacearum and other bacterial strains was tested with 29 different antibiotics. Cephalexin and cycloheximide had no effect on X. c. pv. musacearum but cephalexin inhibited most of the saprophytes and cycloheximide inhibited the fungal contaminants. Based on these studies,
we have developed a semi-selective medium YTSA-CC containing yeast extract (1%), tryptone (1%), sucrose (1%), agar (1.5%),
cephalexin (50 mg l−1) and cycloheximide (150 mg l−1), pH 7.0. The pathogen X. c. pv. musacearum was easily identified as yellowish, mucoid and circular colonies on YTSA-CC medium. This simple semi-selective medium was
effective for isolation of X. c. pv. musacearum from infected banana tissues and soil, and it should be a valuable tool in ecological and epidemiological studies. 相似文献
16.
Maria Pia Argentieri Trifone D’Addabbo Aldo Tava Augusta Agostinelli Marian Jurzysta Pinarosa Avato 《European journal of plant pathology / European Foundation for Plant Pathology》2008,120(2):189-197
The nematicidal activity of saponins from Medicago arborea (tops), M. arabica (tops and roots) and M. sativa (tops and roots) against the plant-parasitic nematode Xiphinema index was investigated. Nematicidal activity of related prosapogenins and sapogenins on X. index is also described. Saponins from Medicago spp. at different concentrations were all nematicidal, those from M. arborea tops being the less effective. In general, saponins induced 100% mortality at 500 μg ml−1 between 8 and 48 h, while prosapogenins resulted in toxicity starting at 125 μg ml−1. Differences in the effects on X. index induced by prosapogenins and sapogenins were less pronounced, although prosapogenins displayed a larger range of activity.
Assays with purified sapogenins demonstrated the relationship of the observed nematicidal activity of M. sativa and M. arborea to the content of the main aglycones (medicagenic acid and hederagenin, respectively) in the saponin extracts. Hederagenin
displayed the highest bioactivity, giving 38% mortality after 1 h at 125 μg ml−1. 相似文献
17.
Anne Moussart Caroline Onfroy Angelique Lesne Magali Esquibet Eric Grenier Bernard Tivoli 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):57-69
Ditylenchus dipsaci, the stem nematode of alfalfa (Medicago sativa), Mycosphaerella pinodes, cause of Ascochyta blight in pea (Pisum sativum) and Aphanomyces euteiches, cause of pea root rot, result in major yield losses in French alfalfa and pea crops. These diseases are difficult to control
and the partial resistances currently available are not effective enough. Medicago truncatula, the barrel medic, is the legume model for genetic studies, which should lead to the identification and characterization
of new resistance genes for pathogens. We evaluated a collection of 34 accessions of M. truncatula and nine accessions from three other species (two from M. italica, six from M. littoralis and one from M. polymorpha) for resistance to these three major diseases. We developed screening tests, including standard host references, for each
pathogen. Most of the accessions tested were resistant to D. dipsaci, with only three accessions classified as susceptible. A very high level of resistance to M. pinodes was observed among the accessions, none of which was susceptible to this pathogen. Conversely, a high level of variation,
from resistant to susceptible accessions, was identified in response to infection by A. euteiches. 相似文献
18.
Yukiko Maeda Mitsuo Horita Hirosuke Shinohara Akinori Kiba Kouhei Ohnishi Seiya Tsushima Yasufumi Hikichi 《Journal of General Plant Pathology》2007,73(1):46-52
Repetitive sequence-based polymerase chain reaction (rep-PCR) analysis using BOX and ERIC as primers showed a highly divergent
phylogeny among field strains of Burkholderia glumae. To elucidate the sources of oxolinic acid (OA) resistance in field strains of B. glumae isolated from rice seedlings cultivated in Mie, Toyama, and Iwate prefectures, Japan, the amino acid at position 83 of GyrA
(GyrA83), which is involved in OA resistance, and the DNA patterns from the rep-PCR and the partial nucleotide sequences of
gyrB and rpoD from various strains were analyzed. The ten Mie strains, in which GyrA83 was isoleucine (Ile), were divided into two groups
based on the band patterns in rep-PCR analysis, although the nucleotide sequences of gyrB and rpoD were identical among the strains. Based on the band patterns in the rep-PCR analysis and the gyrB and rpoD sequences, two highly OA-resistant Toyama strains, Pg-13 and Pg-14, for which GyrA83 was serine (Ser) and Ile, respectively,
were in the same lineage. This suggests that the bacteria might acquire OA resistance faster than phylogenic diversity as
determined with the repetitive sequences BOX and ERIC and with gyrB and rpoD. Furthermore, three Iwate strains (H95, H101, and H104), isolated from seedlings of different cultivars grown in different
years and having Ile at GyrA83, are probably in the same lineage, suggesting that OA-resistant bacteria might be transferred
among different cultivars. 相似文献
19.
Shin-ichi Fuji Nanae Mochizuki Masashi Fujinaga Makoto Ikeda Kouichi Shinoda Seiji Uematsu Hiromitsu Furuya Hideki Naito Fumiyoshi Fukumoto 《Journal of General Plant Pathology》2007,73(3):216-221
Alstroemeria plants were surveyed for viruses in Japan from 2002 to 2004. Seventy-two Alstroemeria plants were collected from Aichi, Nagano, and Hokkaido prefectures and 54.2% were infected with some species of virus. The
predominant virus was Alstroemeria mosaic virus, followed by Tomato spotted wilt virus, Youcai mosaic virus (YoMV), Cucumber mosaic virus (CMV), Alstroemeria virus X and Broad bean wilt virus-2 (BBWV-2). On the basis of nucleotide sequence of the coat protein genes, all four CMV isolates belong to subgroup IA. CMV
isolates induced mosaic and/or necrosis on Alstroemeria. YoMV and BBWV-2 were newly identified by traits such as host range, particle morphology, and nucleotide sequence as viruses
infecting Alstroemeria. A BBWV-2 isolate also induced mosaic symptoms on Alstroemeria seedlings. 相似文献
20.
Helena P. Trenado Isabel M. Fortes Diamantina Louro Jesús Navas-Castillo 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(2):193-196
Tomato chlorosis virus causes yellow leaf disorder epidemics in many countries worldwide. Plants of Physalis ixocarpa showing abnormal interveinal yellowing and plants of Physalis peruviana showing mild yellowing collected in the vicinity of tomato crops in Portugal were found naturally infected with ToCV. Physalis ixocarpa and P. peruviana were tested for susceptibility to ToCV by inoculation with Bemisia tabaci, Q biotype. Results confirmed that ToCV is readily transmissible to both species. The infection was expressed in P. ixocarpa by conspicuous interveinal yellow areas on leaves that developed into red or brown necrotic flecks, while P. peruviana test plants remained asymptomatic. Infected plants of both P. ixocarpa and P. peruviana served as ToCV sources for tomato infection via B. tabaci transmission. This is the first report of P. ixocarpa and P. peruviana as natural hosts of ToCV. 相似文献