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1.
Hideki Watanabe Yoshihiro Taguchi Mitsuro Hyakumachi Koji Kageyama 《Journal of General Plant Pathology》2007,73(2):81-88
Pythium and Phytophthora species were isolated from kalanchoe plants with root and stem rots. Phytophthora isolates were identified as Phytophthora nicotianae on the basis of morphological characteristics and restriction fragment length polymorphism (RFLP) analysis of the rDNA-internal
transcribed spacer regions. Similarly, the Pythium isolates were identified as Pythium myriotylum and Pythium helicoides. In pathogenicity tests, isolates of the three species caused root and stem rots. Disease severity caused by the Pythium spp. and Ph. nicotianae was the greatest at 35°–40°C and 30°–40°C, respectively. Ph. nicotianae induced stem rot at two different relative humidities (60% and >95%) at 30°C. P. myriotylum and P. helicoides caused root and stem rots at high humidity (>95%), but only root rot at low humidity (60%). 相似文献
2.
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
3.
Biofilm-grown cells of Pseudomonas syringae pv. theae (P.s.theae) wild-type strain K9301 on abiotic surface had remarkable resistance to kasugamycin in comparison to planktonically grown
cells; however, the biofilm-grown cells of K9301 had the same sensitivity to copper sulfate. Because both the lesser biofilm-forming
strain K9301S3 and enhanced biofilm-forming strain K9301-6 also had remarkable biofilm resistance to kasugamycin just as K9301
did and because epigallocatechin gallate, which enhanced biofilm formation of P.s.theae, had no effect on biofilm resistance to kasugamaycin, the degree of biofilm formation was not correlated with the antibiotic
susceptibilities. In addition, K9301 and K9301S3 had less sensitivity to kasugamycin but had high sensitivity to copper sulfate
on nonwounded leaf surfaces. These results indicate a possibility that the mechanism of P.s.theae biofilm resistance to bactericide functions on both abiotic and nonwounded leaf surfaces. 相似文献
4.
Takeshi Toda Toshihiro Hayakawa Joseph Mwafaida Mghalu Shigeharu Yaguchi Mitsuro Hyakumachi 《Journal of General Plant Pathology》2007,73(6):379-387
Isolates of an unidentified Rhizoctonia sp. (UR isolates) were obtained from creeping bentgrass and Kentucky bluegrass with reddish brown sheath and foliar rots.
Because the UR isolates anastomosed with isolates of three varieties of Waitea circinata (var. oryzae, var. zeae, and var. circinata), colony morphology, hyphal growth rate at different temperatures, pathogenicity, sequence analysis of the internal transcribed
spacers (ITS) region of ribosomal RNA genes (rDNA) were compared. The colony color of mature UR isolates was distinct from
isolates of the other three varieties of W. circinata. In pathogenicity tests on creeping bentgrass, the severity of the disease caused by UR isolates was significantly higher
than that caused by the three varieties of W. circinata. Sequence similarities of the rDNA-ITS region between UR isolates and between isolates within each variety were high (97–100%),
but they were lower among isolates from UR and the varieties of W. circinata (88–94%). In a phylogenetic tree based on the rDNA-ITS sequences, UR isolates formed a cluster separate from each of the
clusters formed by the three varieties of W. circinata. These results indicate that the UR isolates clearly differ from the three varieties of W. circinata. We therefore propose that the UR isolates be classified as new Rhizoctonia sp. that are closely related to W.
circinata and that the disease on creeping bentgrass should be called Waitea reddish-brown patch disease (Sekikasshoku-hagusare-byo
in Japanese). 相似文献
5.
Plants constitutively produce a variety of secondary metabolites that have antimicrobial activities against phytopathogens;
however, interactions between these performed antimicrobial compounds and phytopathogens were poorly understood. In this study,
interactions between epigallocatechin gallate (EGCg), which was a major tea catechin that had antimicrobial activities against
varieties of bacteria, and Pseudomonas syringae pv. theae (P.s. theae), the causal of bacterial shoot blight of tea, were investigated. EGCg had less antimicrobial activity against P.s. theae; however, subinhibitory concentrations of EGCg induced biofilm formation. Because biofilms are induced in the presence of
sucrose in the culture medium but not by P.s. theae strains deficient in exopolysaccharide levan production, biofilm induction by EGCg and levan production are closely related.
EGCg increased survival of P.s. theae under dry conditions on nonwounded leaf surfaces in the presence of sucrose. These data indicate the possibility that tea
catechins affect the survival of P.s. theae on the phyllosphere.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
Tetsuo Tamada 《Journal of General Plant Pathology》2007,73(1):76-80
Four lines (designated MR0, MR1, MR2, and M8) from 13 accessions of Beta vulgaris subsp. maritima were selected on the basis of phenotypes produced after foliar rub-inoculation with Beet necrotic yellow vein virus (BNYVV). The susceptible phenotype developed bright yellow local lesions, whereas the resistant phenotype had symptoms ranging
from no visible lesions to necrotic lesions at the inoculation site. MR1 and MR2 lines had a resistant phenotype depending
on the isolate and the MR0 line was susceptible to all isolates of BNYVV tested. The M8 line was highly susceptible; the virus
spread systemically and caused severe stunting. These plant lines will be useful for distinguishing BNYVV isolates having
different pathogenicities, especially those controlled by RNA3 and/or RNA5. 相似文献
7.
Antonín Dreiseitl Junmei Wang 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(4):357-368
Four hundred and sixty-one isolates of Blumeria
graminis f.sp. hordei were obtained from eight populations occurring on cultivated barley (Hordeum
vulgare) at four geographically distant locations in China during 2003 and 2004. Their virulence frequency was determined on 30 differential
lines. No isolate was virulent on differential lines possessing the resistance genes Mla1, Mla3, Mla6, Mla7, Mla9, Mla12, Mla13, Mlat, Mlg, Mla10, Mla22, Mla23, Mlp1, Ml(N81) and Mlmw. Virulences to the first nine resistance genes are prevalent in Europe and constitute the main part of genetic distance between
Chinese and European populations. Conversely, no isolate was avirulent on the differential lines possessing the genes Mla8 and Ml(Ch). The frequencies of isolates overcoming the genes Mla2, Mla11, Mlk1 and Mlk2 were .4–9.3%, and frequencies of isolates overcoming the genes Mlh, MlLa, Ml(Bw), Mlra, Ml(Ru2), mlw, MlGa, MlWo and Mlnn ranged from 18.2% to 98.7%. Based on reactions of differential lines possessing the genes Mlk1, Mlh, MlLa, Ml(Bw), Mlra and Ml(Ru2), pathotypes were identified and diversity parameters calculated. Eleven of 22 detected pathotypes were found in both years
and comprised 94.6% of isolates. Generally, the populations from different locations in 1 year were more closely related than
populations collected from the same locations in different years. Complete effectiveness of the resistance genes, for which
no corresponding virulences were found, will allow Chinese breeders to access many modern European barley cultivars that are
fully resistant to powdery mildew in China, including those possessing the non-host resistance gene mlo. 相似文献
8.
Phialophora gregata f. sp. adzukicola, a causal agent of brown stem rot in adzuki beans, produces phytotoxic compounds: gregatins A, B, C, D, and E. Gregatins
A, C, and D cause wilting and vascular browning in adzuki beans, which resemble the disease symptoms. Thus, gregatins are
considered to be involved in pathogenicity. However, molecular analyses have not been conducted, and little is known about
other pathogenic factors. We sought to isolate nonpathogenic and gregatin-deficient mutants through Agrobacterium tumefaciens-mediated transformation (ATMT) for cloning of pathogenicity-related genes. The co-cultivation of P. gregata and A. tumefaciens for 48 h at 20°C with 200 μM acetosyringone resulted in approximately 80 transformants per 106 conidia. The presence of acetosyringone in the A. tumefaciens pre-cultivation period led to an increase in T-DNA copy number per genome. Of 420 and 110 transformants tested for their
pathogenicity and productivity of gregatins, one nonpathogenic and three gregatin-deficient mutants were obtained, respectively.
The nonpathogenic mutant produced gregatins, whereas the gregatin-deficient mutants had pathogenicity comparable to the wild-type
strain. This is the first report of ATMT of P. gregata. Further analysis of these mutants will help reveal the nature of the pathogenicity of this fungus including the role of
gregatin in pathogenesis. 相似文献
9.
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.
Masato Kawabe Kazunori Katsube Takanobu Yoshida Tsutomu Arie Kenichi Tsuchiya 《Journal of General Plant Pathology》2007,73(5):353-359
Twenty-eight isolates of Fusarium oxysporum f. sp. spinaciae (FOS; the causal agent of spinach wilt) collected from Japan were assessed for mating type and subjected to phylogenetic analysis.
Mating type analysis revealed all isolates to be MAT1-2, suggesting that there is no sexual recombination within the population.
Phylogenetic analyses based on nucleotide sequences of the ribosomal DNA intergenic spacer (IGS) and the mating type locus
(MAT1) suggested that FOS is polyphyletic. The cluster analysis based on IGS showed four phylogenetic groups (S1–S4) among the isolates. Two distinct
lineages, S1 and S3, included FOS isolates both of the vegetative compatibility group (VCG) types, 0330 and 0331, demonstrating that VCG differentiation in
FOS may not necessarily reflect the phylogenetic relationships based on IGS and MAT1-2-1. 相似文献
12.
Yasuhiro Inoue Seiji Tsuge Jun Ohnishi Takayuki Matsuura Hirokazu Ochiai Hisatoshi Kaku Koji Azegami 《Journal of General Plant Pathology》2007,73(5):365-369
Xanthomonas
oryzae pv. oryzae strain T7174R is lysed by bacteriophage OP1h and OP1h2. Three mutants tolerant to both OP1h and OP1h2 were isolated by transposon mutagenesis. The mutants had an insertion of the transposon in XOO1687, which is predicted to
encode a TonB-dependent receptor gene. Plasmid pHMIroNB that contained XOO1687 of T7174R was constructed, and the mutant was
transformed with the plasmid. The transformant recovered sensitivity to OP1h and OP1h2. Electron microscopic analysis demonstrated that OP1h and OP1h2 can adsorb to the wild type and the transformant, but they could not adsorb to the phage-tolerant mutant. These results suggest
that the TonB-dependent receptor gene relates to adsorption and infection of T7174R by OP1h2 and OP1h.
Y. Inoue and S. Tsuge have contributed equally to this work. 相似文献
13.
Olga Afanasenko Nina Mironenko Olga Filatova Doris Kopahnke Ilona Krämer Frank Ordon 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(3):267-280
The genetics of host-pathogen interactions in the Hordeum vulgare – P. teres f. teres pathosystem was studied in twelve resistant barley accessions, i.e. CI 9825, CI 9819, Diamond, CI 4922, CI 5401, Harbin,
c-8755, c-21849, c-8721 c-23874, c-19979, c-15811. F2 analyses of crosses with susceptible genotypes employing various isolates (from Europe, USA, Canada, and Australia) revealed
that resistance is mostly isolate-specific and controlled by one or two genes. Segregation in ascospore progeny from two crosses
between isolates of different origin revealed that avirulence in P. teres is also determined by one or two genes. An epistatic effect of suppressor genes on avirulence genes is proposed for the genetics
of virulence to Diamond, Harbin, CI 5401 and c-8721 in the fungal crosses D (181-6 × A80) and F (H-22 × 92-178/9). Segregation
in F2 of crosses of three new sources of resistance (c-23874, c-19979, c-15811) to the susceptible cv. Pirkka was studied in laboratory
and greenhouse tests by using seven P. teres isolates, i.e. 181-6, d8-3, d8-4, d9-1, d9-4, F4 and F74. In addition, virulence to these barley accessions of ascospore
progeny from crosses of the same isolates was studied. Based on these studies it was concluded that depending on the isolate
used, resistance of c-23874 is determined at least by two genes and in c-19979 and c-15811 by three genes. The results of
this parallel analyses of genetics of resistance and genetics of virulence allows the postulation of a gene–for–gene interaction
in the P. teres – H. vulgare pathosystem. 相似文献
14.
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
15.
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
16.
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
17.
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
18.
The employment of formulatedBacillus subtilis for peanut seeds (Arachis hypogaea cv. ‘Shulamit’) counteracted the destructive effects of the seedborne pathogenSclerotium (Athelia)rolfsii on the nodulation, leghemoglobin and nitrogenase activity of peanuts. Moreover, the changes in crop vigor index, total nitrogen
content and survivability of bothRhizobium spp. andB. subtilis have been related to compatibility and even an occasional synergism between them.
http://www.phytoparasitica.org posting Nov. 12, 2006. 相似文献
19.
Gummy stem blight of balsam pear found in the Kanto district and in the Hokkaido Prefecture was demonstrated to be caused
by Didymella bryoniae (Auerswald) Rehm based on inoculation experiments, molecular analysis, and morphological identification of the pathogenic
fungus. This fungus was also pathogenic to related plants belonging to Cucurbitaceae. The imperfect stage of the fungus was
identified as Phoma cucurbitacearum (Fr.: Fr.) Sacc. based on morphological similarities. 相似文献
20.
Taro Mori Katsumi Ozaki Hiromi Matsusaki Naotaka Matsuzoe 《Journal of General Plant Pathology》2007,73(2):142-146
To study the behavior and mutation of Ralstonia solanacearum in Solanum toxicarium, which is resistant to bacterial wilt, S. toxicarium was grown in aseptic culture and inoculated with R. solanacearum. Although 60%–80% of the inoculated plants were wilting after 2 to 3 days, most wilted plants had recovered by 20 days after
inoculation. The pathogen was reisolated from over 98% of inoculated plant stems, but the percentage of recovery decreased
the closer the isolation sites were toward the upper stem sections. Three colony types, characterized as fluidal white, nonfluidal
red, and a mixture of fluidal white and nonfluidal red, were reisolated from the stems. Nonfluidal red colonies were less
virulent on tomato plants than fluidal white colonies. 相似文献