Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 49, Issue 3
Displaying 1-19 of 19 articles from this issue
  • Wataru IIDA
    1983 Volume 49 Issue 3 Pages 279-281
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Hiroshi YAEGASHI
    1983 Volume 49 Issue 3 Pages 282-284
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Hiroshi TOCHIHARA
    1983 Volume 49 Issue 3 Pages 285-286
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Toru SHIMOMURA
    1983 Volume 49 Issue 3 Pages 287-289
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Naoyuki MATSUMOTO
    1983 Volume 49 Issue 3 Pages 290
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Hideo ISHII
    1983 Volume 49 Issue 3 Pages 291
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Yoshikatsu FUJITA
    1983 Volume 49 Issue 3 Pages 292
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Naoyuki MATSUMOTO, Toru SATO
    1983 Volume 49 Issue 3 Pages 293-298
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Two factors influencing the allopatry of the pathogenic species of Typhula were shown by two experiments. Winter wheat plants were grown in the sun supplemented with artificial light or in the shade to elicit a difference in winter hardiness level. They were inoculated with Typhula incarnata or T. ishikariensis biotype B to specify the physiological conditions of plants favorable for the prevalence of each pathogen; less hardy plants grown in the shade proved to be suitable for both pathegens to thrive since they did severe damage to these plants, but hardier plants grown in the sun were attacked only by T. ishikariensis biotype B. Cultures of T. incarnata and T. ishikariensis biotypes A, B and C were inoculated in pairs or singly against orchardgrass to observe intertaxon competitive interaction. Moderately virulent biotype A was most competitive, followed by least virulent T. incarnata. Most virulent biotypes B and C were least competitive. Niche separation in the pathogenic species of Typhula is discussed in relation to their allopatry.
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  • Ichiro FUJISAWA, Tadanori GOTO, Tsuneo TSUCHIZAKI, Norio IIZUKA
    1983 Volume 49 Issue 3 Pages 299-307
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    A virus was isolated from symptomless asparagus plants (Asparagus officinalis) in Hokkaido. The virus was sap transmissible to 7 species belonging to 4 families, and caused local lesions on Chenopodium spp., Tetragonia expansa, Spinacia oleracea and Gomphrena globosa. The virus was transmitted by Myzus persicae in a non-persistent manner. Sap from infected C. quinoa was infective after heating for 10min at 50C but not 55C, after dilution to 10-3 but not 2×10-4, and after 8 days but not 11 days at 20C. The virus particles were elongated flexuous rods, with a modal length of 746nm×13nm. On the basis of the symptomatology, host range, transmission mode, physical properties, and particle morphology, the virus was identified as asparagus virus 1 described by Hemn (1960). Ultraviolet absorption spectrum of purified virus preparation was characteristic of that of nucleoprotein with an A 260/280 ratio of 1.24. The titer of the antiserum against the virus was 1/512 in ring interface precipitin test. This antiserum reacted positively with the purified virus, but not with some other potyviruses in SDS-agar gel double diffusion test. However, in ring interface precipitin test, the antiserum reacted weakly with turnip mosaic virus, bean yellow mosaic virus and lettuce mosaic virus. Ultrathin sections of infected asparagus leaves showed cytoplasmic inclusions of pinwheel, bundle and laminated aggregates.
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  • Takahiko OTA
    1983 Volume 49 Issue 3 Pages 308-315
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    An antagonistic bacterium belonging to genus Pseudomonas isolated from citrus canker lesions considerably inhibited the multiplication of citrus canker bacterium (Xanthomonas campestris pv. citri) not only in PS medium but also in the tissues of citrus leaves. In PS medium, the lower the concentration of the medium was, the less degree of the inhibition was resulted. It suggests that suppression of multiplication of X. campestris pv. citrt by antagonistic bacterium was not caused by the competition for nutrients. The multiplication of antagonistic bacterium was not supprssed by citrus canker bacterium in PS medium, but rather promoted in the diluted medium. In the citrus leaf tissue inoculated with both bacteria by needle pricking at the same time, the antagonistic bacterium suppressed considerably the growth of X. campestris pv. citri. The suppression, however, was not so remarkable when both bacteria were infiltrated into intercellular spaces. The antagonistic bacterium introduced alone either by needle prick inoculation or infiltration in to citrus leaf tissues increased its number remarkably with in a few days, but subsequently it decreased gradually. In case of mixed inoculation, the multiplication of antagonistic bacterium in the inoculated tissue was greatly enhanced and longevity of the bacterium was extended as compared to those of single inoculation.
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  • Wen-hsiung Ko, Wang-thing Ho
    1983 Volume 49 Issue 3 Pages 316-321
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Moderate numbers of oospores were produced by cross-inducing Phytophthora parasitica on chemically defined media with agar. However, even in the presence of sterols very few oospores were produced in liquid media or when agar was replaced by highly purified agarose. Elimination of agar from defined media also reduced the numbers of oospores produced by self-inducing Phytophthora cactorum in defined media. A new chemically defined medium was developed and used to assess sterol requirement for sexual reproduction in Phytophthora. Addition of lecithin to liquid basal medium greatly increased the numbers of oospores produced by P. parasitica, whereas β -sitosterol at 20μg/ml was ineffective. Lecithin in basal medium also increased oospore production by P. cactorum 550 times over basal medium only, much more than the increase by β-sitosterol. Addition of β-sitosterol at the concentrations of 1, 5, 10 and 20μg/ml to basal medium supplemented with lecithin did not increase the numbers of oospores produced by both P. parasitica and P. cactorum. Vegetative growth of both fungi in basal medium with lecithin was fast and similar to that in V-8 juice medium, but was slow in basal medium with β-sitosterol. Chromatographically purified lecithin from soybean was still very effective in promoting oospore formation, but lecithin from egg yolk and two synthetic lecithins tested were ineffective. The results show that sterols are not essential for sexual reproduction in both P. parasitica and P. cactorum.
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  • II. Resistance Expression and Cytoplasmic Granulation in the Epidermal Cells
    Hironori KOGA, Osamu HORINO
    1983 Volume 49 Issue 3 Pages 322-330
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Electron microscopical studies were carried out to observe cytoplasmic granulation which is observed under a light microscope in the epidermal cells of rice leaves responding resistingly to incompatible races of Pyricularia oryzae Cav. The first obvious changes in the infected epidermal cells of the incompatible combination between race 037 and var. Toride 1 (resistant gene Pi-zt) were invagination of plasma membrane and appearance of lomasome-like structures 24hr after inoculation. Many invaginations in plasma membranes occurred 48hr after inoculation. The invaginated structures of plasma membrane became globular and formed lomasome-like structures. Some globular membrane structures seemed to be detached from the plasma membrane. The outer membranes of lomasome-like structures often disappeared and the vesicles enclosed in the structures were dispersed into the cytoplasm. Degenerated mitochondria and swollen endoplasmic reticula were not observed 36hr after inoculation, but 48hr after inoculation. At 72hr after inoculation, a lot of vesicles of various size (0.1∼1.1μm) were observed in the infected epidermal cells in the inocompatible combination. In the compatible combination between race 037 and var. Koshihikari, such ultrastructural changes as observed in the incompatible combination were rarely observed. The results suggest that the origin of the cytoplasmic granules observed light-microscopically in the infected epidermal cells may not be mitochondria or endoplasmic reticula, but plasma membranes and lomasome-like structures that were originated from plasma membranes. It is indicated that plasma membrane in the epidermal cells of rice is essentially important to initiate the cytoplasmic reaction leading to the specific resistance in the rice blast disease.
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  • Masaki YAMAMOTO
    1983 Volume 49 Issue 3 Pages 331-337
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Incorporating the exogenous DNA to potato epidermis with rubbing by a brush or cotton ball, severe destruction of hairs and their neighboring parts was observed by scanning microscope. Specific fluorescence of ethidium bromide bound to DNA was recognized in the destructed and their neighboring wounded tissues under epifluorescent microscope. DNA from potato hybrid 96-56 (R1 gene) was treated with various restriction enzymes (Eco RI, Bam HI, Hha I and Hae III) and rubbed with a cotton ball on the potato leaves of cultivar Irish Cobbler (r gene) and zoospores of Phytophthora infestans were inoculated. Eco RI treated plot showed no difference with the control (without treating with enzymes), but Hae III and Hha I treated plots showed few flecks. From this result, fleck formation activity of exogenous DNA seemed to be almost completely destroyed by the Hae III and Hha I treatments. Fraction I protein (FIP) in potatoes with different susceptibility to P. infestans was investigated by isoelectrofocussing. Irish Cobbler (gene r) lacks 1 band in the small subunit of FIP as compared with other cultivars used. When the DNA from the hybrid 96-56 (gene R1) resistant to the race O of P. infestans was rubbed on leaves of Irish Cobbler, resistant flecks were recognized besides susceptible lesions, but electrofocussing pattern of the small subunit of FIP showed no band specific to the hybrid 96-56.
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  • Makoto KOJIMA, Akira MATSUBARA, Seiji YANASE, Shigemitsu TORIYAMA
    1983 Volume 49 Issue 3 Pages 338-346
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Barley plants showing yellow dwarf symptoms were found in the barley fields at Nagaoka, Niigata Prefecture in May, 1980. The causal agent was transmitted in a persistent manner by Rhopalosiphum padi to gramineous plants but neither R. maidis nor Schizaphis graminum. Cereals such as barley, wheat, rye and oat exhibited typical yellow dwarf symptoms of stunting and either yellowing or red leaf discoloration. Other plants such as rice, maize, sorghum, Japanease millet, Job's tears and Italian ryegrass showed no symptoms but proved to be symptomless carriers of the agent. Partially purified preparations containing small spherical virus particles about 25nm in diameter were infectious when they were fed by aphids through membranes and the inoculated plants showed typical symptoms caused by barley yellow dwarf virus. Thermal inactivation point of the agent was between 65 and 70C. In the ultrathin sections, electron dense virus-like particles about 22nm in diameter were found only in phloem tissues of affected barley. Based on these results, the causal agent of the disease was identified as barley yellow dwarf virus.
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  • Hiroshi ISHIZAKI, Mitsuru KOHNO, Minoru TSUCHIDA, Masashi UMINO, Yasun ...
    1983 Volume 49 Issue 3 Pages 347-351
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    Distribution of thiophanate-methyl-resistant strains of Venturia nashicola Tanaka et Yamamoto was surveyed in 1976-1980 at the Kawahara area, Karasu town, Mie prefecture, where Japanese pear had been severely damaged by the occurrence of tiophanate-methyl-resistant strains in 1975. The detection rate of resistant isolates was 93-96% in 1976 through 1980, suggesting the slow recovery of population of senitive strains at the Kawahara area. On the other hand, the detection rate of resistant isolates in 1977 through 1980 was 1.01% at the former Mie Univ, farm and other places where any preparation of thiophanate-methyl or benomyl had never been used. This result suggests that a few number of thiophanate-methyl-resistant strains of V. nashicola have occurred in nature. The present study supports our previous conclusion that the occurrence of the resistant strains at the Kawahara area in 1975 might be due to the selective elimination of the sensitive strains by the extensive use of thiophanate-methyl, resulting in the predominance of the resistant strains.
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  • Meisaku KOIZUMI
    1983 Volume 49 Issue 3 Pages 352-360
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    In attached citrus leaves wounded and incubated in a low humidity environment, hypertrophy and subsequent cell divisions were observed at inner 5-6 cell layers apart from the wound and followed by development of meristem tissues composed of thin dividing cells (TDC-layer).Cell walls of parenchyma outside the TDC-layer became lignified. Infection by Xanthomonas campestris pv. citri was completly inhibited after formation of the TDC-layer. In detached leaves wounded and incubated in a moist environment, irregular cell divisions following hypertrophic changes were observed from 1 to 6 cell layers bordering the wound, but any TDC-layers were not observed. Incubation period from wounding to occurrence of cell divisions was immutable irrespective of humidity. The wound tissues incubated in a moist environment were highly susceptible to infection by X. c. pv. citri until the cell walls in the outer tissues were lignified. Therefore, the susceptible period to infection was about 2 times longer than that of attached leaves incubated in a low humidity. Wound healing was most rapid at 30-35C and markedly retarded below 20C. Overwintering leaves in the field were susceptible to infection for about 20 days or more when wounded in January to early March, and for about 10 days when wounded in mid March to April. Strong winds or any other wound-causing factors, even if they accompanied no rainfall, are concluded as important factors for the occurrence of citrus bacterial canker disease.
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  • Katsumi AKUTSU, Keido KO, Tomomasa MISATO
    1983 Volume 49 Issue 3 Pages 361-366
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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  • Toshiki SHIOMI, Miyoji SUGIURA
    1983 Volume 49 Issue 3 Pages 367-370
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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    A disease of water dropwort, characterized by yellows and stunting of the plants, was found in Kanazawa City, Ishikawa Prefecture in 1980. Electron microscopic studies revealed the presence of numerous mycoplasma-like organisms (MLOs) in the phloem tissues of diseased plants. Both the disease and garland chrysanthemum witches' broom, collected at neighbouring field, were transmitted by Macrosteles orientalis Virbaste. Of 25 species of plants in 14 families, which were inoculated by the leafhopper, 23 plants were infected with the MLOs. The two MLO diseases had the same wide host range similar to that of sickle hare's ear yellows.
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  • 1983 Volume 49 Issue 3 Pages 371-443
    Published: July 25, 1983
    Released on J-STAGE: February 19, 2009
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