Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 53 , Issue 2
Showing 1-22 articles out of 22 articles from the selected issue
  • Takao GOTO, Koushi NISHIYAMA, Kan-ichi OHATA
    1987 Volume 53 Issue 2 Pages 141-149
    Published: April 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Eighty-three pathogenic bacteria were obtained from diseased grains of rice plants which were collected from various localities in Japan during the period from 1973 to 1980. These bacterial isolates were divided into 4 groups according to their bacteriological characteristics and pathogenics traits, and identified as follows: the 1st group of 14 isolates was Pseudomonas glumae; the 2nd group of 16 isolates was P. syringae pv. aptata; and the 3rd group of 26 isolates was a species related to P. fluorescens. The 4th group of 27 isolates belongs to a genus other than Pseudomonas and was not identified. These four groups were easily distinguished by the following characteristics: relation to free oxygen; requirement of growth facters; ability to grow under 40C; production of green fluorescent pigment; activity of oxidase and arginine dihydrolase and nitrate reductase. Antiserum to the isolate NIAES 1169 of P. glumae reacted with the isolates of P. glumae but did not react with the isolates belonging to the other 3 groups of bacteria. All the isolates of 4 groups attacked grains of rice plants and produced similar early symptoms to each other, but the only isolate of P. glumae attacked rice seedlings.
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  • Satoshi WAKIMOTO, Makoto ARAKI, Kenichi TSUCHIYA
    1987 Volume 53 Issue 2 Pages 150-158
    Published: April 25, 1987
    Released: February 19, 2009
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    Serological specificity of Pseudomonas glumae, the pathogenic bacterium of grain rot disease of rice, was tested by means of the agglutination and agar gel diffusion methods using rabbit antisera prepared by injecting living whole cell suspension of Ps. glumae strains, Ku8101, N7505 and N7501. In agglutination method, the antisera were not completely specific to Ps. glumae but their titers obtained with the bacteria other than Ps. glumae were extremely low. Agar gel diffusion test indicated that serological specificity of Ps. glumae depended upon the kind of antisera used, viz., anti-N7501-serum prepared with living whole cells of the strain N7501 was completely specific for Ps. glumae producing no precipitin band with any bacteria other than Ps. glumae. The other two antisera also produced specific band with Ps. glumae strains, suggesting the existence of some antibodies specific to Ps. glumae in these antisera, but they also produced faint precipitin bands with many pseudomonads. When antigens heated at 100C for 1hr were used, all of the three antisera showed almost complete specificity to Ps. glumae in agar gel diffusion test.
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  • Facine KALO, Takeshi TANIGUCHI
    1987 Volume 53 Issue 2 Pages 159-167
    Published: April 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A procedure was shown for obtaining inhibitor of virus infection from the sap of spinach leaves. The leaf sap was brought to 50% saturation with solid ammonium sulfate. The precipitate was suspended in neutral phosphate buffer (PB) and filtrated through a Sephadex G-100 gel column. The active fractions were combined and further purified by DEAE cellulose and CM-Sephadex C-25 column chromatographies. The purified inhibitor lost its inhibitory activity by heating at 100C for 10min. The inhibitor inhibited TMV infection on bean and tobacco, while it showed no or a little effect on Chenopodium amaranticolor. When the inhibitor was treated on the undersurface of bean leaves and TMV was inoculated on the uppersurface, the weak inhibitory activity was observed. The inhibitor adsorbed on the leaf surfaces could not be easily removed by Triton X-100 treatment. The inhibitor also showed inhibitory activity to TMV-RNA infection on bean leaves. This reaction was not due to contamination of ribonuclease in the inhibitor preparation.
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  • Yuji NAGAI
    1987 Volume 53 Issue 2 Pages 168-174
    Published: April 25, 1987
    Released: February 19, 2009
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    Technique for producing attenuated mutant of pepper strain of tobacco mosaic virus (TMV-P) by heat treatment and effectiveness of the mutant for cross protection were investigated. To produce an attenuated virus mutant, heat treatment at 35C for 2 weeks, successfully adopted for tomato strains of TMV, was not successful for TMV-P because of very poor multiplication of the virus. However, when incubated at 35C for 14-16 days after pre-incubation at 25C for 3-4 days, TMV-P including some attenuated mutants multiplied sufficiently. Sweet pepper stems inoculated mechanically with TMV-P were incubated under such temperature conditions as described above. Then, an attenuated mutant of TMV-P designated C-1421 was selected from over 1, 000 single local lesion isolates on Nicotiana tabacum cv. Bright Yellow. The C-1421 was not only symptomless or very mild mottling on pepper seedlings of various cultivars, but also protective against mechanical challenge inoculation with severe TMV-P.
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  • Katsumi AKUTSU, Yasumasa TAKATSU, Hajime SAKIYAMA, Satoshi OKUYAMA
    1987 Volume 53 Issue 2 Pages 175-181
    Published: April 25, 1987
    Released: February 19, 2009
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    Spreading lesions were formed on cucumber leaves (cv. Sagami-Hanjiro) when inoculated with conidia of Botrytis cinerea in the presence of KH2PO4 in the droplet of conidial suspension containing glucose. In the KH2PO4 solution, development of the lesion was earlier than the development in inosine solution containing glucose. Light microscopy of infection processes of the fungal conidia indicated that it penetrated the epidermis both from the primary and the secondary appressoria without significant defense reactions of the host cells in the presence of KH2PO4 in the inoculum. On cucumber leaves pre-treated with KH2PO4 solution, formation of spreading lesions was not found even in glucose solution. The light microscopy revealed that penetration from the primary appressoria was arrested by defense reactions of the epidermal cells, e.g. deposition of well-developed papillae and hypersensitive cell death. Also, formation of the secondary appressoria was not observed. From these results, it was suggested that KH2PO4 acts to enhance the penetration activity of B. cinerea, but not to suppress of resistance reaction in cucumber leaves.
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  • Takashi TSUGE, Noriki HAYASHI, Syoyo NISHIMURA
    1987 Volume 53 Issue 2 Pages 182-190
    Published: April 25, 1987
    Released: February 19, 2009
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    Auxotrophic mutants were isolated from the Japanese pear pathotype, apple pathotype and saprophyte of Alternaria alternata, respectively, after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Among these mutants, the occurrence of revertants (prototrophs) were detected only from the Met and Tyr mutants of the saprophyte of A. alternata. The two Arg mutants from A. alternata apple pathotype decreased their pathogenicity to apple, due to the decrease of their ability to produce AM-toxin. The other auxotrophic mutants from the apple pathotype and Japanese pear pathotype of A. alternata exhibited almost the same pathogenicity as those of the respective parent isolates. When the spores of Arg mutants from A. alternata apple pathotype were inoculated to apple leaves in the presence of arginine, they recovered pathogenicity and AM-toxin production. Heterokaryons were formed when complementary auxotrophs between the Japanese pear pathotype and the apple pathotype of A. alternata were paired on a minimal medium. All protoplasts prepared from complementing mycelia were heterokaryotic. Both heterokaryons, Cho1 (AK-toxin producer)×Cho3 (AM-toxin producer) and Cho2 (AK-toxin producer)×Arg1 (AM-toxin producer), were pathogenic to Japanese pear and weakly pathogenic to apple.
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  • Noboru SHIRANE, Takayuki HATTA
    1987 Volume 53 Issue 2 Pages 191-197
    Published: April 25, 1987
    Released: February 19, 2009
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    A mineral salt (MS) medium suitable for culturing Botrytis cinerea in vitro is described. The MS medium contains trisodium citrate, MnSO4, MgSO4, ZnSO4, NH4NO3, KH2PO4, CaCl2, Na2MoO4, vitamin A palmitate, and sucrose. B. cinerea grew vigorously and sporulated numerous conidia in MS agar-medium similarly to those in potato sucrose (PS) agarmedium. The growth was poor if any one of the components in MS medium was omitted. Especially when MgSO4, NH4NO3, KH2PO4 or sucrose was omitted, almost no growth of the mycelium was resulted, suggesting these components appear to be essential. When cucumber leaves were inoculated with the spores suspended in the MS medium the symptom of gray mold rot appeared, but the symptom did not appear when inoculation was made with spores suspended in distilled water. However, the omission of NH4NO3, KH2PO4 or sucrose from the MS medium led to remarkable decrease of infection. A large number of protoplasts with little cell wall debris were isolated by the standard isolation technique6) from 40hr-old mycelium which were cultured in the MS medium. These protoplasts reverted to mycelium at 30-60% after they were incubated in the reversion medium.
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  • Jee-song CHEN, Fang-ming THSENG, Wen-hsiung Ko
    1987 Volume 53 Issue 2 Pages 198-202
    Published: April 25, 1987
    Released: February 19, 2009
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    Dead twigs of unknown cause standing among healthy twigs with normal green leaves in the same bush of tea have been observed frequently in Taiwan since 1955. Macrophoma theicola was isolated from 102 of 104 diseased twigs collected from various cultivars at different locations. Three weeks after inoculation with wheat-oat grains colonized by M. theicola, more than 86% of inoculated twigs showed die-back symptoms similar to those observed in nature. Macrophoma theicola was reisolated from all of the experimentally infected twigs. All control twigs remained healthly during the experiment. Twigs inoculated with M. theicola grown on potato dextrose agar failed to show any disease symptoms. Macrophoma theicola thrived at relatively high temperature and endured low water potential. The fungus was able to grow about 0.3cm linearly in 2 days at 38C and in 5 days at -71 bars.
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  • Hiroshi YAEGASHI, Izumi MATSUDA, Zenji SATO
    1987 Volume 53 Issue 2 Pages 203-209
    Published: April 25, 1987
    Released: February 19, 2009
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    Appressoria-like structures (ALS) were formed at the tips of hyphae of the blast fungus in Petri dishes containing PDA or water agar. Some of them germinated in PDA media and produced again a relatively small appressorium at the tip of hypha germinated from the primary appressorium. The ALS were pigmented brown to olive, granular, smooth and thick walled. They were variable in size and shape, but mostly globose, ovoid or oblong, and 4-11μm (mean 10.1μm) in diameter. ALS were formed in all isolates used. More ALS were formed in plastic Fetri dishes than in glass ones. On the detached leaf sheaths of rice plants ALS adhered firmly to the host surface, from which the fungus penetrated into the host by piercing the outer walls of epidermal cells with a penetration peg. Susceptible blast lesions developed on the leaf blades of rice plants inoculated with mycelial agar blocks. Susceptible lesions also developed on the leaf sheaths of rice plants inoculated by injecting mycelial suspension. Micrographs of ultrathin sections revealed that ALS were covered with a mucilaginous substance and their walls were relatively thick and more electron-opaque than those of hyphae. From these observations of morphological and functional features, we concluded that ALS of hyphae are appressoria identical to the ones formed by germ tubes from conidia. This is the first report confirming that appressoria form at the hyphal tips of the blast fungus.
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  • Takatoshi ONOE, Masaaki YOSHIKAWA, Hajime MASAGO, Hirosuke SAGAWA
    1987 Volume 53 Issue 2 Pages 210-226
    Published: April 25, 1987
    Released: February 19, 2009
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    Glyceollin, a phytoalexin produced by soybeans, partially and completely inhibited growth of young hyphae of Phytophthora capsici in liquid culture at 20 and 50μg/ml, respectively, within 4hr of incubation. Glyceollin at the same concentrations induced electrolyte leakage from hyphae immediately following the treatment and inhibited incorporation of an amino acid or nucleoside into an acid soluble “pool” fraction of hyphae. Oxygen uptake by hyphae was also inhibited by glyceollin but only after a lag period of several minutes. These results suggested that the possible primary mechanism of glyceollin action on the fungal hyphae was to interfere with the functions of plasma membrane. Ultrastructural study showed that glyceollin at the inhibitory concentrations induced characteristic alterations in the structure of fungal plasma membranes at early stages (30 to 60min) following treatment, while membrane systems of intracellular organelles remained relatively undamaged. Plasma membranes of the glyceollin-treated hyphae were flattened compared to those of the untreated hyphae and separated from cell walls at some places, and vesicle-like structures were observed between the plasma membranes and cell walls. Furthermore, plasma membranes appeared to be absent from some portions of the cell periphery. In contrast to glyceollin, some toxicants such as cycloheximide and 2, 4-dinitrophenol at the doses that completely inhibited hyphal growth did not induce significant distortion in the structure of plasma membranes, although the latter inhibitor induced electrolyte leakage as rapidly as did glyceollin. These results suggest that the observed distortion in plasma membrane structure is not a nonspecific general response of fungal hyphae due to growth inhibition caused by a variety of toxicants, but it appears to be a characteristic morphological symptom induced by glyceollin. Possible use of this morphological parameter in evaluating the role of glyceollin in soybean disease resistance is suggested.
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  • Masaaki YOSHIKAWA, Takatoshi ONOE, Hajime MASAGO, Hirosuke SAGAWA
    1987 Volume 53 Issue 2 Pages 227-241
    Published: April 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    When soybean (cv. Harosoy 63) hypocotyls were inoculated with Phytophthora capsici, a nonpathogen of soybean, the fungus grew in the hypocotyls until 8 to 10hr after inoculation but then growth was strongly inhibited. This growth inhibition was accompanied by rapid accumulation of a phytoalexin glyceollin. No fungal growth inhibition was observed, however, in hypocotyls treated with blasticidin S, in which glyceollin accumulation was greatly suppressed, and a completely susceptible-type disease symptom appeared in the treated hypocotyls.
    Ultrastructure of P. capsici hyphae in resistant-responding hypocotyls at 12 or 15hr after inoculation exhibited the characteristic plasma membrane abnormalities that were indistinguishable from those observed in the fungus treated with glyceollin in vitro. Typical plasma membrane flattening and separation from cell walls with small vesicles in the intervening space as well as disappearance of plasma membrane from some portions of fungal cytoplasmic periphery were observed. Such plasma membrane distortion in the fungus was not observed, however, in the corresponding hypocotyls treated with blasticidin S, nor in the untreated hypocotyls at 5hr after inoculation when glyceollin accumulation had not been initiated. These results appear to support the contention that glyceollin is indeed active in situ in inhibiting fungal growth during the expression of resistance in soybean hypocotyls.
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  • Norio SAHASHI, Jiko SHISHIYAMA
    1987 Volume 53 Issue 2 Pages 242-249
    Published: April 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Defense reaction of barley cultivars to three nonpathogenic fungi were studied microscopically to clarify whether there are differences among cultivars and the nature of nonhost resistance was discussed by comparing with that of race-specific resistance. In all barley cultivars and non-pathogenic fungi combinations, it is shown that the penetration failure by non-pathogenic fungi was almost associated with papilla formation and cell wall alteration which fluoresced under fluorescence microscopy, of leaf epidermal cells. It is therefore suggested that papilla formation and cell wall alteration associated with defense reaction is major components of nonhost resistance in barley. In addition these components of nonhost resistance are most likely related to the induced resistance caused by previous inoculation with hypo-and hyper-virulent pathogens.
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  • Naoyuki MATSUMOTO, Akitoshi TAJIMI
    1987 Volume 53 Issue 2 Pages 250-253
    Published: April 25, 1987
    Released: February 19, 2009
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  • Yoshiyuki TAKAHASHI, Toshihiro OMURA, Kenichiro SHOHARA, Tsuneo TSUCHI ...
    1987 Volume 53 Issue 2 Pages 254-257
    Published: April 25, 1987
    Released: February 19, 2009
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  • Yasuo ANDO, Nobuyoshi NARISAWA, Masaomi ONIKI
    1987 Volume 53 Issue 2 Pages 258-261
    Published: April 25, 1987
    Released: February 19, 2009
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    The shoot blight of tea plant causing sever damage to tea production in Japan was etiologically investigated. This disease was found to be caused by the tea gray blight fungus, Pestalotia longiseta. The tea brown blight fungus, Glomerella cingulata, was often detected on the diseased shoots, but it was considered to be a secondary parasite.
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  • Hiroshi KAMIUNTEN, Satoshi WAKIMOTO
    1987 Volume 53 Issue 2 Pages 262-265
    Published: April 25, 1987
    Released: February 19, 2009
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  • Susamto SOMOWIYARJO, Nobumichi SAKO, Fukuji NONAKA
    1987 Volume 53 Issue 2 Pages 266-268
    Published: April 25, 1987
    Released: February 19, 2009
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  • Masato IKEGAMI, Takeshi OSAKI, Tadao INOUYE
    1987 Volume 53 Issue 2 Pages 269-273
    Published: April 25, 1987
    Released: February 19, 2009
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  • 1987 Volume 53 Issue 2 Pages 274a
    Published: 1987
    Released: February 19, 2009
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  • 1987 Volume 53 Issue 2 Pages 274b
    Published: 1987
    Released: February 19, 2009
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  • 1987 Volume 53 Issue 2 Pages 274c
    Published: 1987
    Released: February 19, 2009
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  • 1987 Volume 53 Issue 2 Pages e1
    Published: 1987
    Released: February 19, 2009
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