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1.
F. Ismaeil K. Al-Jabor A. Myrta M. J. Mando E. Al-Saadoun M. Hassan S. Al-Chaabi 《EPPO Bulletin》2006,36(1):65-68
A survey was conducted to evaluate the sanitary status of pome fruit trees in Syria during spring 2003 and 2004 in 6 governorates: Damascus, Al-Qunaitara and Al-Sweida (Southern region), Homs and Hama (Central region) and Latakia (Costal Western region), as the main production areas of pome fruits. Leaf samples from 1077 apples, 54 pears and 14 quince were collected and tested for the presence of Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV) and Apple mosaic virus (ApMV) in 70 commercial orchards and 3 varietal collections by ELISA. Results showed that the virus infection rates were 34 and 2% in apple and pear, respectively. Quince trees were found to be virus tested free. ACLSV was prevailing on apple with 34%, whereas ASGV and ApMV were found in 2 and 0.2% of tested trees, respectively. Pear trees were infected only with ACLSV (2%). 21 apples and 15 pears representative budwood samples were indexed by grafting on the following indicators: (i) Malus pumila cvs. Virginia Crab and Radiant for apple and (ii) M. pumila cv. V. Crab and Pyrus communis cv. Nouveau Poiteau for pear. The virus infection rates by woody indexing were much higher than ELISA, Apple stem pitting virus (ASPV) and ASGV were found in 86 and 82% of apple tested samples, whereas they were 80 and 60% of pear tested samples, respectively. Additional RT-PCR testing carried out for a limited number of samples confirmed the high incidence of ACLSV ASPV, ASGV and the presence of ApMV. This is the first report on pome fruit viruses in Syria, indicating an unsatisfactory sanitary status of the industry. As a consequence, a certification program is recommended for producing locally healthy propagating material. 相似文献
2.
Hiroki Noda Noriko Yamagishi Hajime Yaegashi Fei Xing Jipeng Xie Shifang Li Tao Zhou Tsutae Ito Nobuyuki Yoshikawa 《Journal of General Plant Pathology》2017,83(2):83-90
The causal agent of apple mosaic disease has been previously thought to be solely caused by apple mosaic virus (ApMV). In this study, we report that a novel ilarvirus is also associated with apple mosaic disease. Next-generation sequencing analysis of an apple tree showing mosaic symptoms revealed that the tree was infected with three apple latent viruses (apple stem pitting virus, apple stem grooving virus, and apple chlorotic leaf spot virus) and a novel ilarvirus (given the name apple necrotic mosaic virus (ApNMV)) that is closely related to Prunus necrotic ringspot virus (PNRSV) and ApMV. The genome of ApNMV consists of RNA1 (3378 nt), RNA2 (2767 nt), and RNA3 (1956 nt). A phylogenetic analysis based on the coat protein amino acid sequences indicated that the novel virus belongs to the same subgroup 3 of the genus Ilarvirus as PNRSV and ApMV. The presence of mosaic leaves, which tend to be unevenly distributed in diseased apple trees, was correlated with the internal distribution of ApNMV. RT-PCR detection of mosaic-diseased apple trees in Japan indicated that ApNMV was detected in apple trees introduced from China, whereas ApMV was detected from cultivated apple trees in domestic orchards. Consistent with these findings, a survey of mosaic-diseased apple trees in major apple-producing provinces in China revealed that the majority of apple trees showing mosaic symptoms in China are infected with ApNMV. 相似文献
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M. Wenneker K. T. K. Pham M. E. C. Lemmers F. A. de Boer P. J. van Leeuwen T. C. Hollinger F. G. van de Geijn B. P. H. J. Thomma 《European journal of plant pathology / European Foundation for Plant Pathology》2017,148(1):213-217
In a survey for postharvest diseases of apples and pears in the Netherlands, an unknown postharvest fruit rot was observed. The disease appeared to originate from infected lenticels. A fungus was consistently isolated from the decayed fruits. The fungal pathogen was isolated on potato dextrose agar, and at low temperatures development of a fast-growing whitish mycelium was observed. Growth of this fungus was observed between 1 and 20 °C with an optimum at 15 °C, while incubation of mycelium at 25 °C resulted in no growth. The isolates did not produce asexual or sexual spores. The isolates were characterized and identified by morphology and molecular phylogenetic analysis. Genomic DNA was isolated and amplified using ITS1-ITS4, EF1 and RPB2 primers, and BLAST searches in GenBank placed the fungus taxonomically in the genus Fibulorhizoctonia, with the highest matches to F. psychrophila. Pathogenicity of representative isolates from apple and pear fruit was confirmed under laboratory conditions. To the best of our knowledge this is the first report of F. psychrophila causing lenticel spot on apple and pear, and also the cause of a whitish mould on storage bins. 相似文献
6.
H. A. Th. Van Der Scheer 《European journal of plant pathology / European Foundation for Plant Pathology》1971,77(3):65-72
Phytophthora cactorum was isolated from soil of strawberry fields and from an apple and a pear orchard, using hard apples and pears as traps. Pears gave better isolation of the fungus. Isolates from diseased strawberry rhizomes and strawberry-field soil were much less pathogenic to stems and stem and branch pieces of apple variety Cox's Orange Pippin than isolates from apple stem, pear fruit, and orchard soils. Each group of soil isolates showed differences with respect to length and number of the resulting cankers in apple stem and branch pieces.Samenvatting De isolatie vanP. cactorum uit boomgaardgrond en uit grond an aardbeivelden slaagde het beste door gebruik te maken van harde perevruchten. De schimmel groeide uit de grond in de vruchten en kon door overbrengen van een stukje weefsel van de rand van de vruchtaantasting op aardappel-glucose-agar voedingsbodem geisoleerd worden (Tabel 1). Isolaties uit grond van aardbeivelden waren veel minder pathogeen dan isolaties uit appel- of pereboomgaardgrond, indien ze geïnoculeerd werden in ongeveer 35 cm lange stam- en takstukken van het appelras Cox's Orange Pippin, welke in vochtige turfmolm bij 20°C geplaatst waren (Tabel 2). Evenzo vertoonden isolaties uit aangetaste aardbeirhizomen een geringe pathogeniteit voor stammen en stam- en takstukken van Cox's Orange Pippin in vergelijking met isolaties uit appelstam en perevrucht (Tabel 2 en 3 en Fig. 1). De meeste sterk infektieuse isolaties veroorzaakten grote kankers, doch enkele waren maar weinig virulent. 相似文献
7.
Yansu Song Ni Hong Liping Wang Hongju Hu Rui Tian Wenxing Xu Fang Ding Guoping Wang 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(2):183-196
Apple chlorotic leaf spot virus (ACLSV) isolates from sand pear (Pyrus pyrifolia) were characterized by analyzing the sequences of their coat protein (CP) genes and serological reactivity of recombinant
coat proteins (rCPs). The sequences of CP genes from 22 sand pear isolates showed a high divergence, with 87.3–100% identities
at the nucleotide (nt) level and 92.7–100% identities at the amino acid (aa) level. Phylogenetic analysis on the aa sequence
of CP showed that the analyzed ACLSV isolates fell into different clusters and all isolates from sand pear were grouped into
a large cluster (I) which was then divided into two sub-clusters (A and B). Sodium dodecylsulfate-polyacrylamide gel electrophoresis
(SDS-PAGE), western blot and enzyme-linked immunosorbent assay (ELISA) analyses demonstrated that rCPs of eight ACLSV isolates
(PP13, PP15-2, PP24, PP43, PE, PP54, PP56 and ACLSV-C) from two sub-clusters had different mobility rates and serological
reactivity. The rCPs of five isolates grouped into the sub-cluster A showed stronger reactivity with antibodies against rCPs
of a sand pear isolate ACLSV-BD and virions of a Japanese apple isolate P-205 than that with the antibody against a Chinese
apple isolate ACLSV-C. Three isolates grouped into the sub-cluster B showed stronger reactivity with the antibody against
ACLSV-C. The antigenic determinants of CPs from these eight isolates and isolates ACLSV-BD and P-205 were predicted. These
results contribute to a further understanding of molecular diversity of the virus and its implication in serological detection. 相似文献
8.
Diversity of the coat protein-coding region among Ilarvirus isolates infecting hop in Australia 总被引:1,自引:0,他引:1
D. R. Crowle S. J. Pethybridge G. W. Leggett L. J. Sherriff C. R. Wilson † 《Plant pathology》2003,52(5):655-662
Coat protein (CP) sequences of 17 Ilarvirus isolates were obtained from hops at three farms in Tasmania, Australia. Phylogenetic analysis of these sequences and additional database sequences indicated several Apple mosaic virus (ApMV) isolate clusters distinct from Prunus necrotic ringspot virus (PNRSV): one containing isolates from apple; one containing a single isolate from almond; a third containing Australian hop isolates of the 'apple' serotype and a German isolate of unknown origin; and a fourth containing Australian hop isolates of the 'intermediate' serotype. Isolates from hop, pear and prune from the Czech Republic either formed a fifth grouping, or were divergent members of the 'intermediate' serotype group. Deduced amino acid (aa) residue differences between the coat proteins of the two hop isolate serotype groups were highlighted as possible regions of serological differentiation. No evidence for coinfection of plants with both serotypes was found. Tests of ApMV-infected hop buds using the Shirofugen flowering cherry assay revealed a possible differentiation of the two strains based on hypersensitivity. Because of serological similarities to PNRSV, these viruses have commonly been reported as strains of PNRSV. However, this study shows ilarviruses from Australian hops are strains of ApMV, but distinct from those infecting Malus spp. 相似文献
9.
In the last 10 years, more than a thousand almond trees have been analysed by the DAS-ELISA method in the Valencia region. The most frequent virus infecting unselected almond trees was prune dwarf ilarvirus (PDV) (62%), followed by prunus necrotic ringspot ilarvirus (PNRSV) (36%), apple mosaic ilarvirus (ApMV) (14%) and apple chlorotic leafspot trichovirus (ACLSV) (2%). Infection levels of selected trees were 26% for PDV, 15% for PRSV, 0% for ApMV and 5% for ACLSV. 相似文献
10.
Megumu Tanahashi Takashi Nakano Hajime Akamatsu Motoichiro Kodama Hiroshi Otani Kumiko Osaki-Oka 《European journal of plant pathology / European Foundation for Plant Pathology》2016,145(4):787-795
A disease caused by Alternaria alternata occurred on the leaves of European pear cultivar Le Lectier in Niigata Prefecture, Japan, and was named black spot of European pear. In conidial inoculation tests, the causal pathogen induced not only small black lesions on the leaves of European pear cultivar Le Lectier, but severe lesions on the leaves of apple cultivar Red Gold, which is susceptible to the A. alternata apple pathotype (previously called A. mali) causing Alternaria blotch of apple. Interestingly, the apple pathotype isolate showed the same pathogenicity as the European pear pathogen. HPLC analysis of the culture filtrates revealed that A. alternata causing black spot of European pear produced AM-toxin I, known as a host-specific toxin of the A. alternata apple pathotype. AM-toxin I induced veinal necrosis on leaves of Le Lectier and General Leclerc cultivars, both susceptible to the European pear pathogen, at 5?×?10?7 M and 10?6 M respectively, but did not affect leaves of resistant cultivars at 10?4 M. PCR analysis with primers that specifically amplify the AM-toxin synthetase gene detected the product of expected size in the pathogen. These results indicate that A. alternata causing black spot of European pear is identical to that causing Alternaria blotch of apple. This is the first report of European pear disease caused by the A. alternata apple pathotype. This study provides a multiplex PCR protocol, which could serve as a useful tool, for the epidemiological survey of these two diseases in European pear and apple orchards. 相似文献
11.
Peng Zhao Makoto Kakishima Shihomi Uzuhashi Hideo Ishii 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(2):245-258
Isolates of Venturia species isolated from pear in Japan, China, Taiwan and Israel were used in this study to analyze their molecular phylogenetic
relationship. The nucleotides of rDNA-ITS, partial β-tubulin and elongation factor 1α genes were sequenced directly after
PCR. Based on these sequence data two phylogenetic groups could be distinguished. Isolates collected from Asian pears such
as Japanese and Chinese pears formed a distinct evolutionary lineage from those derived from European and Syrian pears. This
result corroborated the early taxonomic separation of V. nashicola from V. pirina. In addition, trees from single-locus data sets and the combined data set showed that all isolates of V. nashicola were included in a monophyletic group and representative isolates of five pathological races originating from different locations
and cultivars formed a single lineage. In contrast, two distinct evolutionary lineages were revealed in V. pirina and isolates of five races were scattered in two lineages. Israeli isolates of race 2 as well as two Japanese isolates of
V. pirina formed a distinct lineage from other isolates of this species, while other Israeli isolates belonging to races 1, 3, 4, and
5 were closely related to each other and formed another lineage. It was indicated that the evolution of pathological races
in V. nashicola might have occurred relatively recently as compared with V. pirina. 相似文献
12.
Dana Vašková Karel Petrzik Josef Špak 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(6):573-580
Sequences of the capsid protein gene and the preceding intergenic region of eleven isolates of prune dwarf virus from central Europe were determined. The isolates were obtained from plum, cherry and peach trees. Comparison of all sequenced isolates (including two sequences published previously) revealed high (88%) conservation of the capsid protein gene. The highest degree of identity was observed in the C-terminal half, where only 13 amino acid substitutions could be observed in contrast to the N-terminal half with 22 substitutions. No reasonable correlation between amino acid substitutions and host species and/or geographic origin of the isolates was observed. Alignment with capsid protein genes of other ilarviruses revealed apple mosaic virus, elm mottle virus, lilac ring mottle virus and prunus necrotic ringspot virus as the most related to prune dwarf virus. Unlike the isolates of related prunus necrotic ringspot virus all the isolates of prune dwarf virus shared extensive conservation of the intergenic region. Portions of RNA3 were selected for design of universal primers for PCR detection. 相似文献
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Lukáš Predajňa Nina Sihelská Daniela Benediková Katarína Šoltys Thierry Candresse Miroslav Glasa 《European journal of plant pathology / European Foundation for Plant Pathology》2017,147(4):877-885
Although Prune dwarf virus (PDV) is one of the most common viruses infecting stone fruits (Prunus spp.), most of the molecular diversity studies have so far focused on the capsid protein (CP) gene. An alternative diagnostic primer pair targeting the movement protein (MP) gene was used in the present work, increasing then polyvalence of PDV detection in cherry samples from Slovakia as compared to the previously published primers amplifying 5′MP-intergenic region-CP-3′UTR fragment. The nearly complete sequence of the RNA3 from 24 Slovak PDV isolates was determined, together with 19 partial sequences of the MP gene for other isolates. Even though the isolates originated from a geographically limited region, analyses showed a high degree of nucleotide sequence diversity between isolates. No clear-cut phylogenetic grouping based on host or geographical origin could be observed. The topology of the MP and CP trees were incongruent for some isolates. Highly supported recombination signals were detected in five PDV isolates, with breakpoints located at different positions in the central part of RNA3, within or close to the intergenic region. Taken together these results extend our understanding of the variability of PDV and for the first time highlight the contribution of recombination to the evolutionary history of this virus. 相似文献
14.
B. J. THOMAS 《Plant pathology》1984,33(2):155-160
Symptoms induced in rose by single isolates of the cherry serotype of prunus necrotic ringspot virus (PNRSV) and an apple serotype (apple mosaic virus; ApMV) were characteristically different, and appeared at different times throughout the growing season according to the ambient temperature. These features remained discrete, even in roses infected by both viruses and were shown by immunospecific electron microscopy to be a reliable indication of infection by either virus.
However, cross-protection between the two isolates was not reciprocal; mixed infections were established only when roses were simultaneously graft-inoculated with ApMV and PNRSV, or when PNRSV-infected roses were supei-infected with ApMV. The significance of these results in relation to the possible natural occurrence of mixed infections in rose or of isolates of intermediate serotype is discussed. 相似文献
However, cross-protection between the two isolates was not reciprocal; mixed infections were established only when roses were simultaneously graft-inoculated with ApMV and PNRSV, or when PNRSV-infected roses were supei-infected with ApMV. The significance of these results in relation to the possible natural occurrence of mixed infections in rose or of isolates of intermediate serotype is discussed. 相似文献
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Zhong-Bin Wu You-Xiu Zheng Chiou-Chu Su Chung-Jan Chang Fuh-Jyh Jan 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(1):71-79
A putative virus-induced disease of pear (Pyrus pyrifolia var. Hengshen) showing symptoms of reduced size of foliage and leaf distortion was observed in orchards in central Taiwan
in 2004. The sap of symptomatic leaf samples reacted positively to an antiserum against Apple stem grooving virus (ASGV). Two virus cultures, designated as TS1 and TS2, were isolated from symptomatic pears. Flexuous filamentous virions
of ∼ 12 × 600 nm were observed in symptomatic pear leaves and purified virus preparations. Results of back inoculation of
pear seedlings with TS1 revealed that ASGV was the causal agent of the disease. Sequence analyses of the cloned coat protein
(CP) genes of TS1 and TS2 shared 88–92.4% nucleotide and 90.7–97.1% amino acid identities with those of other ASGV isolates
available in GenBank. The polyclonal antibody generated against ASGV TS1 has been routinely used for the detection of the
ASGV-infection in the imported pear scions for quarantine purpose via enzyme-linked immunosorbent assays (ELISAs). One of
1,199 samples of pear scions imported from Japan during 2005–2007 was identified as ASGV-positive and the virus was designated
as AGJP-22. The CP gene amplified from this AGJP-22 shared 97.9–98.3% amino acid identities to those of the domestic isolates
and they were closely related phylogenetically. To date, these data present for the first time conclusive evidence revealing
that ASGV is indeed the causal agent of the pear disease displaying symptoms of reduced size of foliage and leaf distortion
in Taiwan. 相似文献
17.
A collection of 205 strains ofErwinia amylovora isolated in Israel over a period of 12 years has been established. The strains were isolated from different varieties of
pear, apple, loquat and quince grown in Israel, and collected from different locations in the country. They were characterized
in respect to degree of virulence on several hosts and serological and molecular characters. Pathogenicity tests carried out
on flowering branches of pear and apple, shoots of pears, and on trees of pear and loquat grown in containers outdoors, revealed
no significant differences in the severity of blossom blight or shoot blight among the various strains. ELISA and immunofluorescence
assays revealed no serotypic groups among the Israeli strains. Genomic diversity was studied by random amplified polymorphic
DNA (RAPD) analysis using 24 arbitrary 10-base primers. All the strains examined (45 Israeli and 11 from Egypt, Cyprus and
Greece) produced the same RAPD patterns with each of the primers used. Amplification patterns were indistinguishable from
those produced by strains isolated from the neighboring countries. Results presented in this study suggest that the population
ofE. amylovora in Israel is homogenous. 相似文献
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Thomas Thomidis 《Phytoparasitica》2001,29(1):47-49
The relative virulence ofPhytophthora cactorum andP. syringae originating from almond trees, and ofP. citrophthora originating from citrus, to apple, pear, peach, cherry and plum rootstocks, was studiedin vivo andin vitro. Results of the different experiments were in good agreement. All testedPhytophthora isolates showed little virulence to pear rootstocks-causing only minor crown rot symptoms - and no virulence at all to apple
rootstocks. In contrast, they were highly virulent to stone fruit rootstocks, causing crown rot disease. The non-pathogenicity
of these isolates to pome rootstocks could be interpreted as strict host specificity. 相似文献
20.
Henk J. Schouten 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(1):21-32
Since 1984 when a new Ministerial Regulation on fire blight came into force, there have been 20 protected regions in the Netherlands, where nurseries of rosaceous plants, and pear and apple orchards are extra protected against fire blight. This policy is also necessary to meet the requirements of the European Community (EC) on fire blight. Two of the measures in the protected regions are the prohibition of flowering of the native hawthorn (Crataegus monogyna andC. laevigata), and destruction of blighted plants. In the unprotected regions, flowering is allowed, and destruction of blighted plants is limited to a zone of 500 metres around orchards.For three years, the effectiveness of preventing flowering of hawthorn in protecting pear orchards against fire blight infection was studied in the field. Five test areas of about 3 km × 3 km were chosen with hawthorns and pear orchards. Two of these areas were in protected regions and three in unprotected regions. The more than 50 000 hawthorns in the areas were grouped into 1125 sites of hawthorn. The 126 orchards larger than 0.2 ha contained about 180 000 trees.During the three years light to moderate epidemics of fire blight were observed in the regions. Fire blight occurred in 2.3% of the non-flowering sites and 19.8% of the flowering (or fruiting) sites at least once in 1987, 1988 or 1989. The prohibition of flowering for hawthorn in protected areas was rather well implemented, so that in protected areas a smaller proportion of sites of hawthorns had fire blight (4.1%) than in unprotected areas (14%). Moreover, there were fewer sites per square kilometre in the protected areas (13) than in the unprotected areas (26).In protected areas, 53% and in unprotected areas 59% of the pear orchards had fire blight during 1987, 1988 or 1989. The difference was not significant. The first reason for the ineffectiveness of the preventing of flowering prevention in hawthorn to control fire blight in pear orchards was the inadequate hygiene of the pear orchards in both types of region. If it be assumed that a new focus is most probably initiated by the nearest existing focus, the second reason was that fire blight hardly spread from hawthorn to pear in the period of this study. Spread of fire blight within pear orchards and between pear orchards occurred frequently. 相似文献