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1.
Judith Hübschen Lilo Kling Ulrike Ipach Volker Zinkernagel Nathalie Bosselut Daniel Esmenjaud Derek J.F. Brown Roy Neilson 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):779-788
Xiphinema diversicaudatum and X. index are vector nematode species of economic importance in viticulture regions as they can transmit Arabis Mosaic, Grapevine Fanleaf and Strawberry Latent Ringspot viruses to grapevine. Wang et al. (2003) designed species-specific diagnostic primers from ribosomal genes for both these vector species as well as a vector and a non-vector species X. italiae and X. vuittenezi, respectively. Our study aimed to confirm the specificity and determine the sensitivity and reliability of the primers for the two vector species, X. diversicaudatumand X. indexwhen challenged with closely related longidorid species and general nematode communities typical of vineyard soil. With one exception, no PCR product was observed when the primers were tested against six Longidorus, one Paralongidorus and one Xiphinema non-target species. Occasionally (three out of eight replicate PCR reactions) a weak PCR product was noted when primers for X. index were tested with L. elongatus. Furthermore, when challenged with a range of non-target nematode species comprising the nematode community typical of viticulture soil, no PCR product was amplified. An experimental dilution series of extracted DNA rigorously demonstrated that DNA from an equivalent single specimen of the target virus-vector species, X. diversicaudatum and/or X. index, could be detected amongst 1000 equivalent non-targetX. vuittenezi. Also, extracted DNA from an equivalent single target specimen was detected when added to DNA extracted from the overall soil nematode community. The primers were assessed further by using serial mixtures of actual nematodes rather than extracted DNA to simulate field soil. Using this method, a single target nematode could be detected amongst 200 non-target specimens. Given their specificity, sensitivity and reliability, it appears that these diagnostic primers will be of great benefit to phytosanitary/quarantine services related to the viticulture industry. 相似文献
2.
Sílvia Tavares João Inácio álvaro Fonseca Cristina Oliveira 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(10):973-982
The ascomycetous fungus Taphrina deformans is the agent of peach leaf curl, a worldwide disease of peach potentially devastating to both crop yields and tree longevity. Conspicuous leaf curl symptoms result from the invasion of host tissue by the strictly parasitic mycelial phase of the T. deformans dimorphic life-cycle. Successful isolation of the fungus in pure culture is cumbersome and limited to late spring/early summer (time of ascospore discharge from infected leaves) and only rarely has the asymptomatic yeast phase been isolated from buds. Molecular methods, namely those based on the hybridisation of nucleic acids, are advantageous for diagnostic purposes since they do not require isolation of the fungus on culture media. Direct amplification using the polymerase chain reaction (PCR) and fluorescent in situ hybridisation (FISH) were tested for diagnosis of peach leaf curl disease in order to provide a fast and reliable method for disease risk assessment. Specific primers and probes were designed based on available ribosomal DNA sequence data. Positive and specific diagnoses of peach leaf curl were achieved with primer TDITS1, using PCR-detection, and probe TDE634, using FISH, both on infected leaves and in washings of asymptomatic peach buds. 相似文献
3.
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
4.
Edna Sharon Ilan Chet Ada Viterbo Meira Bar-Eyal Harel Nagan Gary J. Samuels Yitzhak Spiegel 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):247-258
Trichoderma (T.
asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived
eggs and second-stage juveniles (J2) were parasitized by Trichoderma
asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma
asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without
gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi.
The gelatinous matrix specifically induced J2 immobilization by T.
asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation
of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca2+-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes.
All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated
nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching
and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated
in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of
Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism. 相似文献
5.
P.V. Martínez-culebras P. Abad-campos J. García-jiménez 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(8):801-809
Acremonium
cucurbitacearum is a soil-borne pathogen that causes collapse of muskmelon and watermelon plants. Cluster analysis based on RAPD patterns, obtained from use of 25 primers, divided isolates of A. cucurbitacearum from Spain and USA into two major groups. Most isolates from the USA fell into group 1, however, genetic similarity was not highly correlated with geographical origins or with previously established VCG groups. Analysis of 5.8S-ITS sequences showed very little sequence variation among isolates of A. cucurbitacearum, most had identical 5.8S-ITS sequence. Nodulisporium melonis, previously reported to cause a similar disease in Japan, had a 5.8S-ITS sequence that was identical to that of isolate A-419 proposed as the type strain of A
cremonium
cucurbitacearum suggesting that the two fungal pathogens should be considered a single species. Phylogenetic analysis, based on the 5.8S-ITS region, indicated that A
cremonium
cucurbitacearum is a monophyletic taxon more closely related to Plectosphaerella cucumerina than to other species of the genus Acremonium. Based on the 5.8S-ITS nucleotide sequence, a polymerase chain reaction was designed and used for specific detection of A. cucurbitacearum in diseased plants. 相似文献
6.
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
7.
Kasumi Takeuchi Keisuke Tomioka Hiroshi Kouchi Tomomi Nakagawa Hisatoshi Kaku 《Journal of General Plant Pathology》2007,73(5):336-341
A wilt disease of the model legume Lotus japonicus was observed in a greenhouse in Tokyo, Japan in May 2004. Roots of diseased plants were rotted and dark brown with lesions
spreading to lower stems and leaves, resulting in rapid plant death. The causal agent was identified as Fusarium solani based on the morphology. Sequence analysis of rDNA supported the identification. Inoculation of roots of healthy plants with
conidia reproduced characteristic disease symptoms, and F. solani was reisolated from lesions, satisfying Koch’s postulates. The isolate also caused chlorotic to necrotic lesions on leaves
of healthy plants after wound-inoculation. Infection by F. solani of leaves of L. japonicus was confirmed histologically. Mycelia were observed in the intercellular spaces of parenchymatous tissues in the lesion area
and the surrounding tissues. This is the first report of fungal disease on L. japonicus satisfying Koch’s postulates. We named it “Fusarium root rot of L. japonicus” as a new disease. The compatibility of L. japonicus and F. solani is expected to form a novel pathosystem for studying interactions between legumes and fungal pathogens.
The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AB258993 and
AB258994. 相似文献
8.
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
9.
Michèle L. Largeteau Catherine Regnault-Roger Jean-Michel Savoie 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(2):155-164
The pathogenic fungus Verticillium fungicola, responsible for dry bubble disease of the common mushroom Agaricus bisporus, causes various symptoms on its host, bubbles (undifferentiated spherical masses), bent and/or split stipes (blowout) and
spotty caps. Host DNA quantification by real-time PCR was used to observed relationships between the type of symptom and the
relative amount of A. bisporus and V. fungicola in diseased mushrooms. Verticillium fungicola is involved in bubble formation but does not appear to regulate its growth. Quantifications in bubbles and stipe-bubbles
(morphology between bubble and sporophore with stipe blowout) showed that the pathogen has no effect on the growth of undifferentiated
host hyphae but prevents morphological differentiation if not initiated and stops it when initiated hyphae are affected. Mushrooms
with stipe blowout exhibiting both mature and abortive lamellae reveal that V. fungicola has a restricted area of action in host tissues. Despite their visual aspect, healthy looking parts of mushrooms showing
spots or stipe blowout were actually contaminated. Discolouration and symptom development are two distinct events. The colour
of the tissues was correlated to the percentage of A. bisporus DNA, suggesting that discolouration is not an efficient defensive mechanism, and occurs at the time V. fungicola developed enough to induce tissues necrosis. 相似文献
10.
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
11.
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
12.
Mara Quaglia Antonio Zazzerini 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):393-400
Diaporthe helianthi the causal agent of sunflower (Helianthus annuus) stem canker, causes significant reductions in yield and oil content in most sunflower-growing areas. With the aim of enhancing
host resistance, we selected in vitro sunflower calli against culture filtrates of two pathogen isolates (7/96 and 101/96).
This technique may be an effective and rapid tool to discriminate the most virulent D. helianthi isolate and to screen for host resistance in the early stage of a breeding programme. Further investigation on the mechanisms
involved in defence pathways showed no induction of salicylic acid and pathogenesis-related proteins in calli, indicating
that the host resistance is not associated with Systemic Acquired Resistance but probably other biochemical mechanisms. 相似文献
13.
Willows (Salix spp.) are beneficial as a potential source of renewable energy, riparian barriers and riverbank control, yet are considered
invasive weeds when they clog watercourses and lead to erosion and flooding. Interactions between willow rustMelampsora epitea (Thüm.) (Uredinales: Melampsoraceae) and leaf beetlePhratora spp. (Coleoptera: Chrysomelidae) feeding damage have an impact on effective pest management and biological control. The present
study investigated the effects of(a) prior mechanical leaf damage on rust development, and(b) rust infection on beetle feeding under laboratory conditions for different time intervals and levels of damage. Willow rust
infection significantly reduced the amount of leaf area consumed by beetles. The result was similar when a compatible or an
incompatible rust pathotype was sprayed ontoSalix viminalis (L.) ‘Mullatin’ plants. There were no overall significant effects of mechanical damage on rust development, although the
lowest level of rust infection was found with the incremental damage treatment. There were, however, differences of significance
for leaf position and damage status, with damaged leaves at all positions having fewer pustules and a smaller pustule area
than the corresponding undamaged leaves. There was no detectable effect of possible volatile emissions from crushed willow
leaves on rust infection and development, although the volatile compoundcis-3-hexenyl acetate significantly reduced pustule diameter and overall pustule area. The results are discussed in terms of
the implications for pest management and biological control.
Corresponding author
http://www.phytoparasitica.org posting April 6, 2003. 相似文献
14.
Á. Mesterházy T. Bartók G. Kászonyi M. Varga B. Tóth J. Varga 《European journal of plant pathology / European Foundation for Plant Pathology》2005,112(3):267-281
Different sets of wheat genotypes were tested under field conditions by spraying inocula of isolates of seven Fusarium spp. and Microdochium nivale (formerly F. nivale) in the period 1998–2002. The severity of Fusarium head blight (FHB), Fusarium-damaged kernels (FDK), the yield reduction and the deoxynivalenol (DON) contamination were also measured to describe the nature of the resistance. The degrees of FHB severity of genotypes to F. graminearum, F. culmorum, F. avenaceum, F. sporotrichioides, F. poae, F.␣verticillioides, F. sambucinum and M. nivale were very similar, indicating that the resistance to F.␣graminearum was similar to that for other Fusarium spp. listed. This is an important message to breeders as the resistance relates not only to any particular isolate of F. graminearum, but similarly to isolates of other Fusarium spp. This holds true for all the parameters measured. The DON contamination refers only to DON-producers F. graminearum and F. culmorum. Highly significant correlations were found between FHB, FDK, yield loss and DON contamination. Resistance components such as resistance to kernel infection, resistance to DON and tolerance were identified in the more susceptible genotypes. As compared with western European genotypes which produced up to 700 mg kg−1 DON, the Hungarian genotypes produced only 100 mg kg−1 at a similar FDK level. This research demonstrates the importance of measuring both FDK and DON in the breeding and selection of resistant germplasm and cultivars. 相似文献
15.
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
16.
Sara Fondevilla José I. Cubero Diego Rubiales 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):53-58
Mycosphaerella pinodes is one of the most devastating pea pathogens. Pea cultivars with adequate levels of resistance to control the disease are
not so far available. However, promising levels of resistance have been identified in wild accessions of pea. In the present
investigation the inheritance of resistance to M. pinodes was studied in two crosses between the susceptible pea cv. ‘Ballet’ and the partially wild resistant accessions P665 (Pisum sativum subsp. syriacum) and P42 (P. sativum subsp. sativum var. arvense). Both additive and dominant effects were important in control of resistance and susceptibility dominated over resistance. 相似文献
17.
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
18.
C. Eynck B. Koopmann G. Grunewaldt-Stoecker P. Karlovsky A. von Tiedemann 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):259-274
The differential interactions of V. longisporum (VL) and V. dahliae (VD) on the root surface and in the root and shoot vascular system of Brassica napus were studied by confocal laser scanning microscopy (CLSM), using GFP tagging and conventional fluorescence dyes, acid fuchsin
and acridin orange. VL and VD transformants expressing sGFP were generated by Agrobacterium-mediated transformation. GFP signals were less homogenous and GFP tagging performed less satisfactory than the conventional
fluorescence staining when both were studied with CLSM. Interactions of both pathogens were largely restricted to the root
hair zone. At 24 h post-inoculation (hpi), hyphae of VL and VD were found intensely interwoven with the root hairs. Hyphae
of VL followed the root hairs towards the root surface. At 36 hpi, VL hyphae started to cover the roots with a hyphal net
strictly following the grooves of the junctions of the epidermal cells. VL started to penetrate the root epidermal cells without
any conspicuous infection structures. Subsequently, hyphae grew intracellularly and intercellularly through the root cortex
towards the central cylinder, without inducing any visible plant responses. Colonisation of the xylem vessels in the shoot
with VL was restricted to individual vessels entirely filled with mycelium and conidia, while adjacent vessels remained completely
unaffected. This may explain why no wilt symptoms occur in B. napus infected with VL. Elevated amounts of fungal DNA were detectable in the hypocotyls 14 days post-inoculation (dpi) and in
the leaves 35 dpi. Root penetration was also observed for VD, however, with no directed root surface growth and mainly an
intercellular invasion of the root tissue. In contrast to VL, VD started ample formation of conidia on the roots, and was
unable to spread systemically into the shoots. VD did not form microsclerotia in the root tissue as widely observed for VL.
This study confirms that VD is non-pathogenic on B. napus and demonstrates that non-host resistance against this fungus materializes in restriction of systemic spread rather than
inhibition of penetration. 相似文献
19.
Hiroyuki UGA Yuki O. KOBAYASHI Kyoji HAGIWARA Yohachiro HONDA Toshihiro OMURA Takahide SASAYA 《Journal of General Plant Pathology》2002,68(4):378-381
The causative virus (isolate No. 4) of gentian (Gentiana spp.) mosaic, which had been identified previously as Clover yellow vein virus (C1YVV) on the basis of host range and serological reactions, was re-identified as Bean yellow mosaic virus (BYMV) on the basis of the nucleotide sequences of the gene for the coat protein (CP) and the 3′-noncoding region, as well
as the predicted amino acid sequence of CP.
Received 16 April 2002/ Accepted in revised form 19 June 2002 相似文献
20.
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