Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 50 , Issue 1
Showing 1-18 articles out of 18 articles from the selected issue
  • Kei OGAWA, Hajimu KOMADA
    1984 Volume 50 Issue 1 Pages 1-9
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Fungal hyphae were often found microscopically in stem vascular bundles of susceptible cultivar of sweet potato to Fusarium wilt, caused by Fusarium oxysporum f. sp. batatas. Some isolates of Fusarium oxysporum obtained from healthy tissues showed remarkable cross-protection against the disease, when they were previously inoculated to the sweet potato sprout before being planted in the infested soil. The isolates were not pathogenic not only to sweet potato but also to several species of major vegetable crops; such as cucumber, bottle-gourd, melon, Japanese radish, cabbage and tomato. Pre-inoculation with the non-pathogenic isolates of F. oxysporum was carried out by dipping fresh cut-end of sweet potato sprout into a bud-cell suspension of the isolates, prepared by shake-culture in potato-sucrose broth. Drenching the infested soil with the bud-cell suspension was insufficiently effective. Only the non-pathogenic isolates of F. oxysporum were effective among 12 pathogenic and non-pathogenic Fusaria belonging to 7 species tested, when they were preinoculated with the same method as described above. Pre-inoculation by dipping the cutend of sprout into a bud-cell suspension (108cells/ml) was as effective in the naturally infested field as a chemical control by dipping them into 500 times of benomyl (50%W.P.) for 30 minutes. Smearing of a condenced suspension to the cut-end of sprouts was also as highly effective as dip treatment. The denser the bud-cell suspension was, and the longer the duration of dipping was, the greater protective effect. Pre-inoculation with the non-pathogenic F. oxysporum is considered to be applied for practical biological control of Fusarium wilt of sweet potato, because it is effective against the disease caused not only by soil-borne but also by the pathogen transmitted from tubers, and it does not require the introduction of any complicated operations.
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  • Takatoshi ONOE, Toshikazu TANI, Hirosuke SAGAWA
    1984 Volume 50 Issue 1 Pages 10-18
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Ultrastructures of the fungus-host cell association in crown-rusted oat leaves were investigated by scanning and transmission electron microscopy. Intercellular hyphae growing in infected host tissues partially contacted the outer surfaces of the mesophyll cells. The projection of the cell wall of mesophyll cells and adherent material at the region of contact with the intercellular hyphae and mesophyll cells were seen by transmission electron microscopy, and the unclear border region was observed in this area by scanning electron microscopy. Haustorial mother cells were delimited from intercellular hyphae by septa. The tip of the haustorial mother cell which was globular at the center turned down forming a hook-shaped apex by which the haustorial mother cell and the mesophyll cell surface were connected. A penetration peg originated from the haustorial mother cell near the tip. It seemed that passage of penetration pegs through the host cell walls was accomplished by both enzyme and mechanical forces. The scanning electron micrographs showed that the haustorial body was ellipsoid and a neckband was on the tubular neck near the haustorial body.
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  • Masayasu INOUE, Machiko HOSAKA, Tsutomu MATSUMOTO
    1984 Volume 50 Issue 1 Pages 19-26
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Hybridoma cells producing monoclonal antibodies were prepared by fusion of mouse myeloma cells and spleen cells derived from a BALB/c mouse immunized with purified preparations of a Japanese common strain of tobacco mosaic virus (TMV-OM). Ascites fluid containing high-titred antibodies against TMV-OM was obtained after injecting 18 cloned hybridoma lines into the peritoneal cavity of pristan-primed BALB/c mice. Antibody titres of these ascites fluid were 100 to 1, 000-fold higher than the titres of culture fluid derived from the hybridoma and had an end point of 1.6×107 in the passive hemagglutination test. Using these monoclonal antibodies, antigenicity of TMV-OM was analyzed by double-immunodiffusion, reverse passive hemagglutination inhibition, and passive hemagglutination. Of 18 monoclonal antibodies from hybridoma lines against TMV-OM, 5 were specific for TMV-OM, 9 reacted with both TMV-OM and a tomato strain of TMV (TMV-T), and 4 were specific for TMV-T. These results indicated that at least three antigenic determinants are present in TMV-OM. In the further test for the monospecificity of these three monoclonal antibodies against. TMV-OM using passive hemagglutination inhibition, it was found that of 6 epitopes, two are associated with TMV-OM specific antibodies, three for antibodies specific to both TMV-OM and TMV-T, and one for TMV-T specific antibodies.
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  • Ho-shii CHANG, Ing-mei SHU, Wen-hsiung KO
    1984 Volume 50 Issue 1 Pages 27-30
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Isolates Pm-1, Pm-2 and Pm-3 of Phytophthora melonis induced Phytophthora parasitica A2, but not A1 mating type to produce oospores, and produced oospores in response to stimulation by P. parasitica A2, but not A1 mating type. The results suggest their ability to produce hormone α1 and responsiveness to hormone α2. These three isolates, therefore, belong to sexuality type 1 of Group I. Isolates Pm-4, Pm-5 and Pm-6 which were capable of producing oospores in single cultures, did not form oospores when paired with themselves or with A2 mating type of P. parasitica. However, pairing with A1 mating type of P. parasitica induced oospore formation in these three isolates. A1 mating type of P. parasitica also produced oospores as a result of the pairing. The results suggest their ability to produce hormone α2 and responsiveness to hormone α1. Because of the involvement of an inhibitory effect in the pairing of these isolates with A2 mating type of P. parasitica, their ability to produce hormone α1 and responsiveness to hormone α2 could not be determined.
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  • Yasuo HOMMA, Yutaka ARIMOTO, Tomomasa MISATO
    1984 Volume 50 Issue 1 Pages 31-38
    Published: January 25, 1984
    Released: February 19, 2009
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    Soybean lecithin is practically used as a fungicide against various vegetable powdery mildews. Since the preventive effect on plants was already established, a study was made on its effect on the growth stage development of cucumber powdery mildew fungus, Sphaerotheca fuliginea and the following results were obtained. 1) Direct spray of lecithin at a concentration of 2, 000ppm inhibited 77% of conidial germination. 2) The hyphal elongation of the lecithin-treated fungus was one half as compared with the untreated one. 3) The lecithin inhibited 33% of conidiophore formation. 4) The number of conidia formed per untreated conidiophore in about 20hr was 5, whereas in the lecithin-treated section a conidiophore produced 1.5 conidia. 5) Treatment of newly produced conidia with soybean lecithin induced shrinkage of the conidia first closer to conidiophore and then farther ones. In addition, lecithin inhibited 73% conidial dispersion.
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  • Mamoru SATO
    1984 Volume 50 Issue 1 Pages 39-45
    Published: January 25, 1984
    Released: February 19, 2009
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    A halo-toxin producing strain Ym5-1 of Pseudomonas syringae pv. mori harboured a single plasmid named as pYM5 of approximately 39 megadalton in molecular weight. Behavior of the plasmid pYM5 in bacterial conjugation and relation of the plasmid to toxin production were examined. A non-conjugative plasmid RSF1010 was introduced into the strain Ym 5-1 by mating with P. syringae pv. tabaci BR2 (RSF1010). When Ym5-1 (RSF1010) thus obtained was mated with E. coli SK1592 or a non-halo strain Ni27 of P. syringae pv. mori, RSF1010 was transferred to recipient cells at a frequency of 10-6 to 10-7. It was confirmed by agarose gel electrophoresis that five out of 107t ransconjugants of the recipient Ni27 contained pYM5 together with RSF1010. These results show that pYM5 is a conjugative plasmid. None of the five isolates of Ni27 (pYM5, RSF1010), however, showed any halo blight symptoms on mulberry leaves. An avirulent mutant of Ym5-1 induced by the transposon insertion still harboured a whole pYM5 which was undistinguishable from that of the wild type by restriction endonuclease Hind III digestion. It was concluded that the halo-toxin productivity is not encoded by pYM5 in the strain Ym5-1.
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  • Yoshiaki CHIKUO, Toshiya SUGIMOTO, Toshimitsu ENDO
    1984 Volume 50 Issue 1 Pages 46-52
    Published: January 25, 1984
    Released: February 19, 2009
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    A disease of sugar beets caused by Colletotrichum dematium was found in Hokkaido in August, 1981. Both root crop and seed crop were injured. In root crop, the symptom mainly appeared as fujiform lesions on petioles. The symptom of seed crop were necrotic spots on stalks, leaves and flowers and greater damage was resulted on the seed crop than on the root crop. The fungus was pathogenic on Chenopodiaceae. Beta vulgaris var. saccharifera, Beta vulgaris var. cicla, Beta vulgaris var. rapa and Spinacia olelacea. Optimum temperature for mycelial growth on PDA was between 20 and 27C. Based on morphological characters and host ranges, the present fungus was identified with C. dematium f. spinaciae. The occurrence of the present disease in fields was different in the degree depending on sugar beet cultivars and this varietal difference was highly correrated with the results of artificial inoculation. In Japan, Nakata et al. first reported the disease as called “Shinba kurogare” disease in 1922. Present fungus is considered the same to that which caused the disease reported by Nakata et al. However, due to the marked difference of symtoms from the previous report, the present authors propose the common name of this disease “Sugar beet Anthracnose”.
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  • Hideyoshi TOYODA, Noboru TANAKA, Tokuzo HIRAI
    1984 Volume 50 Issue 1 Pages 53-62
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The effect of the culture filtrate of Fusarium oxysporum f. sp. lycopersici on the growth of tomato callus, and the induction and selection of resistant callus to the culture filtrate were examined by using callus tissues originated from germinating seeds and axillary buds of tomato. In the plants treated with crude filtrate and Millipore filter-filtered culture filtrate (MFF) of Fusarium, the degree or timing of the wilt occurrence was closely similar in both plants. Autoclaved culture filtrate (AF) also induced the wilt in tomato plants though the occurrence was delayed. Lethal effect of the culture filtrate on tomato callus cells was dose-dependent as examined by FDA-staining and the survival rates of the cells in each callus clump treated with the culture filtrate corresponded to the degree or timing of browning in callus clump. Under a positive selection-condition where wild type cells were completely killed, AF-resistant calli were successfully induced and selected after mutagenization with N-methyl-N'-nitro-N-nitrosoguanidine. However, the MFF-resistant calli were not selected.
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  • Tomio USUGI, Tatsuo KUWABARA, Tsuneo TSUCHIZAKI
    1984 Volume 50 Issue 1 Pages 63-68
    Published: January 25, 1984
    Released: February 19, 2009
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    Enzyme-linked immunosorbent assay (ELISA) was used to detect wheat yellow mosaic virus (WYMV), barley yellow mosaic virus (BYMV) and soil-borne wheat mosaic virus (SBWMV)in leaf and root extracts of infected barley and wheat. The γ-globulin and enzyme conjugated γ-globulin were used at 2μg/ml and 1:800 dilution, respectively. WYMV, BYMV and SBWMV were detected by ELISA in extracts of infected leaves diluted up to 25, 600, 6, 400 and 12, 800 times with phosphate buffered saline containning 0.05% Tween 20 (PBS-T), respectively. In the case of roots, WYMV and BYMV were detected in extracts with 0.1M, pH 7.0 citrate buffer, but not with PBS-T. In ELISA using antisera against WYMV and BYMV, both rice necrosis mosaic and oat mosaic viruses were not detected. ELISA was developed to index large number of plants of the breeding field in place of X-body or electron microscope observation.
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  • Yasuhiko UESUGI, Junko KANO, Osamu KODAMA, Tadami AKATSUKA
    1984 Volume 50 Issue 1 Pages 69-71
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Osamu HORINO
    1984 Volume 50 Issue 1 Pages 72-76
    Published: January 25, 1984
    Released: February 19, 2009
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    This paper reports the results of transmission and scanning electron microscopical examination of water pore apertures in Leersia japonica and Oryza sativa. Emphasis is placed on the interaction between hydathodal invasion of Xanthomonas campestris pv. oryzae and physical structure of water pore. Electron micrographs revealed that the resistance of L. japonica to the hydathodal invasion was attributed to the morphological feature of outer ledges on the upper side of guard cells. The results suggest that well-developed outer ledges in L. japonica prevent the invasion of the causal bacterium.
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  • Hiromitsu FURUYA
    1984 Volume 50 Issue 1 Pages 77-81
    Published: January 25, 1984
    Released: February 19, 2009
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    In 1982 and 1983, eyespot or foot rot of winter wheat, which has not been reported in Japan, was found at first in the Hachirogata reclaimed land in Akita prefecture. The brown and elliptical or “eye” shaped lesions formed on basal leaf sheaths and culms were most diagnostic. The severely infected culms were easily lodged by the wind. The causal fungus was frequently isolated from the diseased tissues and was identified as Pseudocercosporella herpotrichoides (Fron) Deighton based on the morphological characteristics of conidia produced on a dead tiller and on culture medium.
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  • 1984 Volume 50 Issue 1 Pages 82-92
    Published: January 25, 1984
    Released: February 19, 2009
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  • 1984 Volume 50 Issue 1 Pages 92-101
    Published: January 25, 1984
    Released: February 19, 2009
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  • 1984 Volume 50 Issue 1 Pages 101-106
    Published: January 25, 1984
    Released: February 19, 2009
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  • 1984 Volume 50 Issue 1 Pages 106-113
    Published: January 25, 1984
    Released: February 19, 2009
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  • 1984 Volume 50 Issue 1 Pages 114-130
    Published: January 25, 1984
    Released: February 19, 2009
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  • 1984 Volume 50 Issue 1 Pages 131-144
    Published: January 25, 1984
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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