Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 60 , Issue 1
Showing 1-20 articles out of 20 articles from the selected issue
  • Hiroshi MATSUOKA, Hitoshi KUNOH, Issei KOBAYASHI
    1994 Volume 60 Issue 1 Pages 3-12
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The interface between Erysiphe pisi and its nonhost, barley, was investigated by transmission electron microscopy. Coleoptiles of barley inoculated with the fungus were fixed at predetermined time intervals: (1) before penetration; (2) 30min after initiation of coleoptile cytoplasmic aggregation; (3) 15-16hr after cytoplasmic aggregation. When appressoria of the fungus matured on the surface of coleoptiles, the appressoria cell wall was thin and flat where the appressorium was in contact with the coleoptile surface. At this stage of development, no noteworthy changes occurred in coleoptile cells below appressoria. In specimens fixed 30min after the initiation of cytoplasmic aggregation, short penetration pegs from appressoria, breached the coleoptile cell wall and were surrounded by and embedded with papillae. The papillae at this stage were mostly electron-dense with some heterogeneous, electron-lucent regions. A large number of spherosomes appeared around the margin of papillae in cytoplasmic aggregates. Some of spherosomes were attached to the margin of papillae and probably allowed their contents to be deposited into the papillae. In specimens fixed 15-16hr after the initiation of cytoplasmic aggregation, prominent papillae were always found below appressoria which apparently had attempted to penetrate the cell wall of coleoptile. These papillae consisted of multiple, alternately electron-dense and -lucent layers. This suggests that osmiophilic and non-osmiophilic materials were deposited alternately during papilla development which occurred in a period of 15-16hr after the initiation of cytoplasmic aggregation. Thus, the gradual development of papillae probably depends on such a continuous deposition of materials.
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  • Bernardo UENO, Tohru TERAOKA, Daijiro HOSOKAWA, Minoru WATANABE
    1994 Volume 60 Issue 1 Pages 13-19
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Clavibacter michiganensis subsp. michiganensis, causal agent of bacterial canker of tomato, produces phytotoxic glycopeptide which causes wilting on tomato cuttings. In order to select toxin-tolerant callus cells and to produce resistant tomato plants, the biological activities of a crude toxin against tomato plants and callus cells were compared with the pathogenic effects of the bacterium. In callus cells co-cultured with the bacterium, susceptible cultivars had a higher percentage of dead cells than resistant cultivars, which showed apparent differences in resistance. Similar responses were obtained with callus cells treated with a crude toxin precipitated with 30 to 40% saturation of ammonium sulfate. These results paralleled closely inoculation tests to whole plants. In tomato cuttings treated with unheated and heated (120°C, 5min) toxin transpiration rates decreased to 20 to 30% and wilting symptoms occurred both in the resistant and the susceptible cultivars, although the activity of heated toxin was attenuated. This result suggests that heat-labile component(s), such as protein(s), may be associated in the toxin activity, in addition to the heat-stable components, such as polysaccharides.
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  • Yoshihiro OHTSU, Shigematsu KUHARA
    1994 Volume 60 Issue 1 Pages 20-26
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The composition of fruit tissue in the synthetic periclinal chimeras ‘NF-1’ and ‘NF-3’ that had been produced in order to try to give disease resistances into chimera plants were quantitatively analyzed with high performance liquid chromatography for four fiavanone glycosides. In the case of ‘NF-1’, juice sac (Germ layer I) showed a chromatogram very similar to that of ‘Kawano-natsudaidai’. Seed (Layer II), segment wall (Layer II and III), mesocarp (Layer II and III) and big vascular bundle (Layer III) showed chromatograms resembling those of ‘Fukuhara orange’. Similarly, in the case of ‘NF-3’, juice sac (Germ layer I) showed a chromatogram very similar to that of ‘Fukuhara orange’ (F), while the other tissues showed chromatograms very similar to those of ‘Kawano-natsudaidai’ (N). Consequently, the chimeral constitution in fruit of ‘NF-1’ is N-F-F for its first, second, and third germ layers, respectively, and F-N-N for ‘NF-3’. We propose the scientific names Citrus sinensis+natsudaidai for ‘NF-1’ and Citrus natsudaidai+sinensis for ‘NF-3’. We also propose the new variety name ‘FN-1’ instead of the earlier used ‘NF-1’. The proportions of four flavanone glycosides of mother varieties corresponded closely to the respective fruit tissues of ‘FN-1’ and ‘NF-3’. These results suggest that introducing tissue of a disease resistant variety to the second and third germ layers, and tissue of a high quality variety to the first layer will make a chimera tree with both disease resistance and high quality fruit.
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  • Seiji TSUGE, Kappei KOBAYASHI, Hitoshi NAKAYASHIKI, Tetsuro OKUNO, Iwa ...
    1994 Volume 60 Issue 1 Pages 27-35
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    We succeeded in infecting turnip protoplasts with a cloned cauliflower mosaic virus (CaMV) DNA, pCa122, which contains 1.2 copy of CaMV genomic DNA and a plasmid expressing open reading frame (ORF) VI products (pEXP6) using polyethylene glycol. Fluorescent antibody staining showed that up to 50% of protoplasts were infected. It was difficult to detect the progeny DNA and the viral protein in protoplasts inoculated with pCa122 alone. Co-transfection with the plasmid pEXP6 produced larger fluorescing specks in each infected protoplasts and increased the accumulation of the progeny DNA and some other viral proteins to detectable levels. Using this protoplast system, three CaMV ORF I insertional mutants which were not infectious on turnip plants were tested for their infectivity on turnip protoplasts. Viral DNA and products accumulated in infected protoplasts to the same extent of the wild type DNA-infected protoplasts. These results indicate that ORF I product is not required for multiplication of CaMV in protoplasts, but is indispensable for infection on whole plants, strongly supporting that ORF I product is involved in cell-to-cell movement of CaMV.
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  • Soon-Bae KWON, Nobumichi SAKO
    1994 Volume 60 Issue 1 Pages 36-44
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A strain of tobacco mosaic virus (TMV) was isolated from rakkyo plants in Miyazaki Prefecture. This strain was distinguished by reactions on host plants from other strains of TMV occurring in Japan. It systemically infected four Allium species, but did not infect three tomato cultivars tested. In most of the tobacco species or cultivars tested, the symptoms induced by this strain were similar to those by TMV-OM, but the strain did not systemically infect a tobacco cultivar Bright Yellow, and multiplied only in the inoculated leaf without causing any symptoms. Although this strain is similar to TMV-OM in morphology, physical properties and mobility of the coat protein or RNA by electrophoresis, it is serologically discernible from TMV-OM, TMV-L and TMV-P through Ouchterlony agar double diffusion test, intragel cross absorption test in agar gel and DAS-ELISA. These results indicate a new strain of TMV, and the name rakkyo strain (TMV-R) of TMV is hereby proposed.
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  • Nobukazu TANAKA, Atsuhiro OKA
    1994 Volume 60 Issue 1 Pages 45-52
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Agrobacterium rhizogenes strain MAFF 03-01724 isolated from a diseased melon plant bears pRi1724, a mikimopine-type of hairy-root-inducing plasmid. The 9.5-kb region of pRi1724 showed the root-inducing ability toward leaf disks of Ajuga reptans and Nicotiana tabacum. This region contained sequences highly homologous to each of the rolA, rolB, and rolC genes of the agropine-type hairy-root-inducing plasmid pRiA4b. The relative position of the three homologs was the same as that of pRiA4b. These results indicate that pRi1724 carries genes both functionally and structurally equivalent to the rolA, rolB and rolC genes of pRiA4b.
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  • Norio SATO
    1994 Volume 60 Issue 1 Pages 53-59
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The rapidity of indirect germination of the sporangia of Phytophthora infestans was investigated. Sporangial suspensions were prepared from the infected potato tuber slices or disks cultured for various periods at different temperatures. When the suspensions were incubated at 14°C, optimum for indirect germination, sporangia from older cultures could germinate more quickly than those from younger cultures. Sporangia immediately after production could germinate only slowly, while almost all the sporangia aged by preincubation for 6hr or more at 22°C could germinate quickly within 1hr when postincubated at 14°C. Therefore, it was considered that sporangial maturation by aging was essential to acquire the ability of indirect germination, and that matured sporangia could germinate quickly within about 1hr at 14°C. Time required for sporangial maturation was remarkably affected by the air temperature during sporangial production and also by the incubation temperature after preparation of sporangial suspension. The shortest maturation time, about 6hr, was found between 18 and 22°C. Temperatures below 15°C remarkably slowed maturation, and temperatures of 26°C and above inhibited it. Matured sporangia quickly lost the ability of quick germination when the suspensions were incubated at 26°C or above.
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  • Norio SATO
    1994 Volume 60 Issue 1 Pages 60
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The ability of indirect germination of the spores (sporangia) of Phytophthora infestans at different water temperatures was investigated. Spores appeared to have their own limit temperature of indirect germination (LT): only when water temperature was below the LT, spores could germinate. Variation of LT was investigated by using spore suspensions prepared from the infected potato tuber disks cultured for different periods (16, 24 and 48hr) at different air temperatures (12-26°C). The suspensions were incubated for 24hr at different water temperatures (14-25°C). Irrespective of the sporulating air temperatures, in all the suspensions the proportions of germination at below 16°C were equally high. But at different water temperatures between 16 and 20°C the proportions turned to rapid decrease: the decrease from 90 to 10% occurred with increase of only about 3°C. The water temperature limiting germination to 50% (LT50) was fairly affected by sporulating air temperature. When produced at the lower air temperatures of 12 and 15°C, the spores had lower LT50s (17.0-18.6°C), whereas at the higher air temperatures of 24 and 26°C, the spores had higher LT50s (20.5-22.5°C). The LT50 was also somewhat affected by the time of culture period. The spores from the shortest period of cultures usually had somewhat lower LT50s than those from the older ones. Therefore, the level of LT of spores appeared to be determined mainly by sporulating air temperature and secondary by their ages.
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  • Tetsuji YAMADA, Masaharu HAYASHI, Sachiko NAKATSUKA, Keiko MURAYA, His ...
    1994 Volume 60 Issue 1 Pages 66-73
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The accumulation of pisatin in epicotyl tissues of Pisum sativum L. cv. Midoriusui inoculated with compatible races of Pseudomonas syringae pv. pisi (P. pisi) was significantly suppressed comparing to that by the inoculation with a incompatible race. This was reflected by the suppression of the accumulation of phenylalanine ammonia-lyase (PAL)-mRNA in the inoculated tissues. Low molecular mass (MW<ca. 10, 000 Da) substances secreted in the culture filtrates from the compatible race of P. pisi exhibited the suppression of pisatin accumulation, whereas those from the incompatible race did not. The relationship between the suppression of host defense reactions and the specificity of race-cultivar in bacterial disease is discussed.
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  • Masao GOTO, Makiichi TAKAGAKI, Atsushi KODERA, Yuichi TAKIKAWA, Sinji ...
    1994 Volume 60 Issue 1 Pages 74-81
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pseudomonas glumae grew on potato-dextrose agar plates containing benomyl at the concentration of 500 to 1, 000μg/ml depending on the strains, but not at 1, 500μg/ml. The growth inhibition resulted from bacteriostatic action of the chemical. Cultures of the bacterium contained benomyl-resistant mutants at various frequencies depending on the strains. Virulence of these mutants was identical to that of the parent strains. Regardless of the presence of such resistant mutants, seedling rot of rice was effectively controlled by seed-dressing with 0.1% (w/w) benomyl or 0.5 to 1.0% Benlate or Benlate-T. Such suppressive effect was not observed when sterilized rice grains were used. The population of P. glumae was significantly suppressed on benomyl-treated seeds, but rapidly increased on untreated seeds. On the contrary, saprophytic bacteria, particularly fluorescent pseudomonads, substantially increased on benomyl-treated seeds, but not on untreated seeds. The fluorescent pseudomonads inhibited growth of P. glumae in vitro and significantly suppressed development of seedling rot in situ as well. They were identified as P. fluorescens and the production of growth inhibitory substances was confirmed in liquid media. These observations suggested that the efficacy of benomyl against seedling rot of rice resulted mainly from the antagonistic effect of P. fluorescens which preferentially proliferated on the benomyl-treated seeds.
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  • Yoshihiro OHTSU
    1994 Volume 60 Issue 1 Pages 82-88
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    An improved method named DHS (Direction-Hormone-Slowlygrowing)-method for efficient introduction of disease resistance to chimera was developed. The connective part of two hypocotyls {‘Kawano-natsudaidai’ (Citrus natsudaidai Hayata) moderately resistant to CTV and ‘Fukuhara orange’ (Citrus sinensis)} grafted together was cut horizontally. Then the hypocotyl of ‘Kawano-natsudaidai’ of the connective part was further cut at an angle of 60° against the stem direction. The cut surface of the hypocotyls was treated with plant hormones. Each treated hypocotyl was covered with paraffin film and grown under light in the laboratory. A slowly-growing adventitious bud produced on the cut surface of ‘Kawano-natsudaidai’ near to the border of the two varieties was selected and grown in a greenhouse. A synthetic periclinal chimera of citrus composed of Germ layer II & III of ‘Kawano-natsudaidai’ (N) covered with Layer I of ‘Fukuhara orange’ (F) was easily obtained by treatment with a mixture of 50μM gibberellin A3, 1μM 6-benzylaminopurine and 1μM α-naphtaleneacetic acid. The scientific name Citrus natsudaidai+sinensis and the variety name ‘NF-5’ is proposed for the synthetic Periclinal chimera of citrus. The DHS method makes it easy to introduce a tissue resistant to citrus canker and citrus tristeza virus into Layer II & III of citrus. A simple way to identify a variety of a tissue from Layer II & III by HPLC was also established.
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  • Hironori KOGA
    1994 Volume 60 Issue 1 Pages 89-98
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Penetration and colonization of panicle neck tissue of a susceptible line, ZTS of rice by Pyricularia oryzae was investigated by electron microscopy. Embedding of the hard impermeable panicle neck tissue was improved by extending the period of resin infiltration. Penetration pegs pierced the outer cell wall of epidermal cells in such a way which suggested that they produced no more than small quantities of extracellular enzymes. Invading hyphae were present in cells 24hr after inoculation. Successful penetration through stomata was not observed. Collar-like wall appositions (papillae) were observed between the host cell wall and plasma membrane beneath the penetration peg in compartmentalized epidermal cells, but not in decompartmentalized ones. Invading hyphae had colonized sclerenchyma, parenchyma and vascular bundles by 48hr after inoculation. Invasion of the sclerenchyma mainly occurred through pit-pairs, where the host cell wall is especially thin. The host cytoplasm in invaded cells showed signs of degeneration, particularly of chloroplasts in parenchyma cells. Such degeneration would seem to be the cause of the panicle neck rot symptoms of infection by P. oryzae. Conidiophores were formed on the panicle necks 4 days after inocculation.
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  • Shinya TSUDA, Ichiro FUJISAWA, Kaoru HANADA, Soh HIDAKA, Ken-ichi HIGO ...
    1994 Volume 60 Issue 1 Pages 99-103
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Toshiyuki MORIKAWA, Yoshikuni NOMURA
    1994 Volume 60 Issue 1 Pages 104-106
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Norio KONDO, Hisanori SHIMADA, Fujio KODAMA
    1994 Volume 60 Issue 1 Pages 107-108
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Fe M. DELA CUEVA, Antonio C. LAURENA, Marina P. NATURAL, Yuichi YAMAOK ...
    1994 Volume 60 Issue 1 Pages 109-112
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Ken'o OKAYAMA
    1994 Volume 60 Issue 1 Pages 113-118
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Strawberry plants infected with C. gloeosporiodes which causes anthracnose were placed in nursery beds to investigate the relation of the disease spread and the effect of some physical barriers. The dispersion distance of conidia of the pathogen was examined by the appearence of early disease symptoms, black leaf spots, on leaves in every direction. Disease incidence on leaflets and petioles was severe under 0.5m horizontally from the inoculum source, and conidia dispersed more than 3min heavy rain. Vertical spread of disease incidence decreased at a distance from the inoculum source, especially far from 60cm. Barriers of plastic film over 40cm high were effective to prevent the disease spread on strawberry plants. Leaf spots developed when leaflets were inoculated with more than 102 conidia/young leaflet. The number of black leaf spots appeared was correlated with the concentration of conidia in the inoculum (r=0.63, p=0.01). Thus, it was shown that barriers are useful to protect strawberry plants from anthracnose infection on the leaflets due to rain dispersion even in heavy rain.
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  • Masanobu OHASHI, Hiroshi KAMIUNTEN
    1994 Volume 60 Issue 1 Pages 119-121
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A virus was isolated from grain amaranth (Amaranthus hypochondriacus L.) showing mosaic symptoms. The virus infected 20 plant species of 8 families, and was readily transmitted by aphid. The thermal inactivation point of the virus in crude sap was 55-60°C (10min), dilution end point 10-3-10-4, and longevity in vitro 2-4 days at 25°C. The virus was isometric about 28-30nm in diameter, and was serologically indistinguishable from a yellow strain of cucumber mosaic virus (CMV-Y). Electrophoretic patterns of dsRNA of the virus were similar to those of CMVs. Based on these results, the virus was identified as CMV.
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  • Kokichi TAKAHASHI, Hiromi SEGAWA, Takao KOBAYASHI
    1994 Volume 60 Issue 1 Pages 122-127
    Published: February 25, 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A new leaf spot disease of mulberry (Morus alba and M. bombycis) caused by a species of Myrothecium broke out in Kagoshima Prefecture in 1991 and 1992. Inoculation tests confirmed that the causal fungus was pathogenic to 133 species of plants belonging to 96 genera of 45 families. Symptoms were various, depending on plant species, and included necrotic lesions, stem canker or damping-off. Based on morphological, cultural and pathological characters, the causal fungus was identified as Myrothecium roridum Tode: Fries.
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  • 1994 Volume 60 Issue 1 Pages 144
    Published: 1994
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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