摘要:

Efficient transmission of plant viruses has been achieved using specially designed and constructed compressed‐air guns. Minimal puncturing of indicator‐plant epidermal cells, with a silicon carbide particle gun, rendered them highly susceptible to infection with sap inoculum applied by a spray gun. Sensitivity was improved 500‐fold compared with finger rubbing transmissions, and 1000‐fold compared with ELISA methods, as assessed by serial dilutions of infected sap in water. Punctured epidermal cells were observed slowly to extrude beads of cytoplasm, which took some minutes to attain maximum size before gradual retraction was completed 40–60 min later. Leaf susceptibility related to surface area of cytoplasm exposed at any time after cell puncture, suggesting that virus particles were bound to cytoplasm or plasmalemma and were passively carried into the cell. Spray nozzle design and construction materials influenced the infectivity of applied inoculum due to electrostatic charging effects on sprayed

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00011.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Double‐stranded RNA (dsRNA) associated with plum pox virus (PPV) inNicotiana clevelandiiandPrunus domesticahas been isolated. While dsRNA was detected inN. clevelandiiin considerable amounts by electrophoresis, only small amounts were found inP. domestica.This may be due to viscous substances in the leaves of this woody host. Different PPV strains (NAT ‐ not aphid‐transmissible; AT ‐ aphid‐transmissible) showed specific patterns in electrophoresis gels. When PPV was assayed inN. clevelandiiby dsRNA detection or by standard ELISA or ISEM, all three methods were found to be efficient, with none being superior. ELISA, as a simple and fast routine method, is still the method of choice. DsRNA detection will be suitable for plant disease agents undetectable by ELISA

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00012.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

La detection des virus dans les végétaux par la technique immunoenzymatique ELISA exige une certaine préparation des échantillons et la phase de broyage demeure actuellement le principal facteur limitant la réalisation d'un grand nombre de tests journaliers. La présente étude compare les trois techniques les plus souvent disponibles dans un laboratoire: (1) le broyage par disperseurs‐homogénéisateurs travaillant à vitesse très élevée (type Polytron/Kinematica ou Ultra Turrax; (2) l'utilisation d'une presse dans laquelle l'échantillon est écrasé lentement entre deux rouleaux tournant en sens contraires (type MEKU Pollähne); (3) le broyage d'un échantillon conditionné entre deux épaisseurs de gaze dans un sachet individuel de plastique. La dilacération des tissus est assurée par un dispositif à roulements à billes monté sur une perceuse (système Tekan/Inotech). C'est cette dernière technique alliant simplicité, économic et rapidité qui convient ainsi le mieux à un laboratoire assu

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00013.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Crown gall is the most important bacterial disease of grapevine and is primarily associated withAgrobacterium tumefaciensbiovar 3. The systemic distribution of the agrobacteria in grapevine requires the checking of nursery propagation material to reveal their presence in the xylem vessels. The methods adopted to demonstrate systemic survival are quite lengthy and, thus, this study aimed to develop a serological sampling procedure to rapidly detectA. tumefaciensin xylem extracts, obtained by vacuum extraction with suitable washing fluid, from asymptomatic one year‐old dormant grape cuttings. The suspension was centrifuged and the final concentrate used for immunofluorescence staining. The sensitivity threshold of the vacuum washing system and the effectiveness of the detection method were experimentally evaluated. The antiserum specificity was tested in a comparative study with a collection ofA. tumefaciensstrains from grapevine and other common grapevine contaminants. The vacuum washing system is discussed as an indexing tool in a much hoped for certification programm

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00014.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Xanthomonas ampelinacan be detected with the same sensitivity by ELISA double‐antibody sandwich (ELISA‐DAS) or indirect ELISA (ELISA‐I) but the latter is preferred for its greater simplicity. The two methods also gave similar sensitivity results for soft‐rot erwinias, but their application is complicated by the large number of erwinia serotypes. ELISA‐I was unable to distinguish strains ofAgrobacterium tumefaciensfromA. radiobacter.The cross reactions with other bacteria of antisera againstX. fragariaewere tested by ELISA‐I. The problems of applying these methods ar

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00015.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Parmi les nombreux virus qui peuvent infecter l'oeillet cultivé, cinq (carnation mottle virus, carnation ringspot virus, carnation vein mottle virus, carnation necrotic fleck virus, carnation etched ring virus) existent dans tous les pays producteurs où leur impact économique est loin d'être négligeable. L'élimination de ces virus est donc un problème de dimension européenne dont l'importance est aujourd'hui partout reconnue. L'utilisation à grande échelle des méthodes de détection immunoenzymatiques (test ELISA) apparaît comme un moyen particulièrement commode et efficace pour parvenir à une amélioration rapide de l'état sanitaire des oeillets commercialisés. Toutefois les chances de succès dépendent, non seulement des protocoles adoptés pour les tests, mais aussi des conditions dans lesquelles ceuxci sont effectués aux différents stades de multiplication du végétal indexé. Comparé aux autres méthodes de diagnostic, le test ELISA présente indéniablement des avantages, mais il a aussi ses limites qui dépendent de chaque couple virus/hôte considéré. A cet égard, le problème de l'éradication des virus de l'oeillet est un modèle de choix pour illustrer les

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00016.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

An antiserum was prepared against cauliflower mosaic virus strain S. The specificity of the reagents (IgG labelled with alkaline phosphatase) allowed the use of ELISA test (standard method) for virus detection, directly from cauliflower plants. Triton and urea had to be added to the homogenizing phosphate buffer. Labelled antibodies from strain S were also reactive ‐ with high optical densities ‐ against strain PV‐45 and Cabb‐BJI, but a distant relationship appeared with strain CM4‐184. Two thousand samples picked in the field were analysed and some results showed that the virus could be latent in the plant. A good correlation was observed between ELISA and biological indexing results. However, the serological diagnosis was more precise when cauliflowers were doubly infected by cauliflower mosaic virus and turnip mos

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00017.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Corynebacterium wilt of tomato causes severe losses in France and Belgium. The disease can be seed‐transmitted and sanitary selection of seedlots is a direct prophylactic control method. It must be selective, objective and sensitive and must provide information on the pathogenicity of the bacteria detected. A method is proposed that associates immunofluorescence (IF) staining with bioassay and isolation. In a preliminary comparison of inoculation on different host plants, tomato seedlings with two or four leaves were the most sensitive. Artificially and naturally contaminated seed extracts were IF‐screened and confirmed by isolation of the pathogen from inoculated seedlings. The detection method consists of maceration of tomato seeds in PBS‐cycloheximide buffer, filtration and centrifugation of the seed extract, and IF screening of the pellets with two antisera. Pellets with positive or suspect IF reading (threshold 5 × 103cells in the pellet) are inoculated into tomato seedlings incubated at 25°C. Within 30 days the seedlings are inspected for typical wilt symptoms and isolation experiments are carried out from the vessels. The method has been tested on commercial s

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00018.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Antibodies coated onto a suitable solid phase, e. g. polystyrene beads, rods for inoculating agar plates, or petri dishes, enable selective trapping of homologous bacteria and of immunologically related bacteria by immunoaffinity. After washing away unbound organisms, the bound organisms are desorbed and plated on a suitable medium. Selective immunoisolation has been demonstrated for various phytopathogenic bacteria includingCorynebacterium michiganensessp.michiganense, Erwinia chrysanthemi, E. carotovorassp.atroseptica, Xanthomonas campestrispv.begoniaeandPseudomonas syringaepv.phaseolicola.Three serological methods are described for additional rapid immunoidentification of colonies directly on agar plates and for screening for cross‐reacting microorganisms: (a) direct immunodiffusion on dilution plates, (b) agar mixed‐antibody assay, (c) fluorescent antibody colony staining. Schemes are presented for increasing the reliability and sensitivity of sample screening for quality indexing of plant material, and for efficient screening and isolation of possible cross‐reacting microorganisms to enable production of more specific ant

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractLa technique ELISA est utilisée pour évaluer le taux d'infection de lots de graines de soja et de graines de pois, respectivement par le soybean mosaic virus et le pea seed‐borne mosaic virus. Couplée à une méthode d'analyse par groupes, cette technique permet de tester un grand nombre de graines si la précision requise l'exige. Une mise au point préalable est nécessaire pour chaque cultivar à analyser: elle porte sur le nombre maximal de graines par groupe et sur les modalités du broyage dans les conditions de routine. L'analyse des lots de graines peut apporter une double information: lorsque le virus des téguments est pris en compte dans le test, le résultat obtenu est une estimation par défaut du pourcentage de plantes infectées avant la récolte; au contraire, lorsque seul le virus des embryons est dosé, le résultat traduit le pourcentage de sources primaires d'infection lors de la

ISSN:0250-8052    

DOI:10.1111/j.1365-2338.1987.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY