Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 38 , Issue 4
Showing 1-16 articles out of 16 articles from the selected issue
  • Masao GOTO, M.P. STARR
    1972 Volume 38 Issue 4 Pages 267-274
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    When temperate phages of Xanthomonas citri infected other susceptible xanthomonads, these bacteria (X. begoniae and X. phaseoli) were lysogenized and released temperate phages constantly thereafter. The lysogenized bacteria did not lose their lysogenicity after repeated transfer through their original host plants. The lysogenized bacteria sometimes showed great changes in susceptibility to either the temperate phages or the virulent phages. However, no change was noticed in other characteristics, including plant pathogenicity and utilization of carbon sources, indicating that these temperate phages of X. citri did not cause transductions of these characters in these bacteria under the conditions used.
    Download PDF (701K)
  • Hideyuki YAGITA, Yasuo KOMURO
    1972 Volume 38 Issue 4 Pages 275-283
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    When mulberry seedlings were planted in soils brought from mulberry fields where mosaic disease was severe, the seedlings showed ringspot and enation symptoms on the leaves 6 to 17 months after planting, reconfirming Okabe's conclusion (1959) that mosaic is a soil-borne disease.
    From the leaves showing enation and/or ringspot symptoms of these experimentally infected seedling, a virus was isolated by juice inoculation to cowpea, Chenopodium amaranticolor, C. quinoa, and C. murale. In electronmicroscopy, the virus was found to be spherical, about 22mμ in diameter. The virus reacted with antiserum to mulberry ringspot virus prepared by Dr. T. Tsuchizaki, but not with antiserum to tomato black ring virus sent from Dr. B.D. Harrison, Scotland. The virus was identified as mulberry ringspot virus reported by Tsuchizaki et al. (1970).
    The infected soil lost its transmissibility when dried for 7 days. Many nematodes belonging to Longidorus were collected by sieving technique from soil around roots of infected mulberry trees in the fields. The species was identified as L. martini Merny by Mr. Y. Oshima.
    Lots of 10 to 56 L. martini sieved from soil in which diseased mulberry trees had been growing were placed near the roots of 31 potted healthy mulberry plants. After 3 to 12 months, 10 of these plants showed symptoms, and the virus was detected from these 10 plants by juice inoculation to test plants. No infection occurred in 8 control mulberry plants grown in soil free from L. martini.
    Transmission tests using Xiphinema sp. sieved from soil in which diseased mulberry had been growing gave negative results.
    The symptoms on mulberry plants incited by the nematode transmission were ringspots, enations and some vein necrosis, and no fern-leaf and yellow leaf symptoms were observed.
    Download PDF (1760K)
  • Ryozo YOKOSAWA, Akira OGOSHI, Ryutaro SAKAI
    1972 Volume 38 Issue 4 Pages 284-289
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Zoospores of Aphanomyces raphani Kendrick were attracted to and locally accumulated on some parts of roots and hypocotyls of seedlings of non-host plants as well as host plants. Its locally accumulated mass of zoospores extended to 100-500μ in diameter. Relations between this phenomenon and damping-off mechanism in host plant (cabbage seedling) was investigated. Accumulations of zoospores were observed more frequently on hypocotyl, especially on the part adjacent to root, than root. Zoospores germinated and penetrated in mass at the accumulated place on hypocotyl of cabbage seedling and the fungus multiplied in and on the penetrated region. When cabbage seedling was thoroughly dipped into zoospores suspension, penetration and multiplication of the fungus was severer at hypocotyl than at root. Of many inoculation methods with zoospores of A. raphani or with infested soil, damping-off of cabbage seedling was severest in condition that hypocotyls of seedlings came in contact with the pathogen. In contrast, when only roots were exposed to the pathogen, disease incidence was very low or not at all. From these results, damping-off of cabbage seedling by A. raphani seemed to be mainly caused by the mass penetration on hypocotyl.
    Download PDF (1331K)
  • Ryutaro SAKAI, Rinzo SATO, Jiro ITO, Sadao SAKAMURA
    1972 Volume 38 Issue 4 Pages 290-298
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    1. Phyllostine has been isolated from the culture filtrate of Phyllosticta sp., a pathogenic fungus of red clover, as the principal toxic compound causing wilting and dark discoloration of leafy stem cuttings of red clover and it is closely related structurally to phyllosinol.
    2. Phyllostine stimulated growth of red clover, lettuce and rice seedlings at a concentration range from 10-8 to 10-5M. These promoting effects of phyllostine on plant growth were similar to that of phyllosinol.
    3. Phyllostine at concentrations between 10-6 to 2.5×10-4M promoted adventitious root formation in epicotyls of Azukia cuttings. The promoting effect of phyllostine, however, was slightly higher than phyllosinol at the same concentration level.
    4. IAA-induced elongation of isolated Avena coleoptile sections was inhibited by phyllostine at a concentration range from 10-6 to 5×10-4M.
    5. GA3-induced elongation of lettuce hypocotyls was slightly inhibited by phyllostine at a concentration range from 5×10-5 to 10-4M.
    6. Phyllostine has antibiotic activity. The activity of phyllostine, on the whole, was about more than four times as high as that of phyllosinol.
    Download PDF (1619K)
  • Suesaku CHIBA, Junitsu CHIBA, Keise SHIMADA, Hiroshi KAGAWA
    1972 Volume 38 Issue 4 Pages 299-305
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In order to know the effect of the degree of resistance or susceptibility of rice plants to fungal growth on infection rate of blast fungus, various rice varieties were grown in the field where various amounts of fertilizer were top-dressed. The disease increase was measured by lesion number and the degree of resistance or susceptibility of rice plants to blast fungus was estimated by measuring degree of hyphal growth in the leaf sheath cell. Infection rate was calculated by the equation y=y0er(t-t2/2T) or rs=2.3/(t2-t1).·log10y2/y1. The average degree of hyphal growth measured after the first day showing a minimum temperature over 18°C increased by top-dressing or late transplanting. This indicates that the degree of resistance or suscpetibility of rice plant to blast is increased by these treatments. There was found a varietal difference of average degree of hyphal growth. The regression of infection rate (r) on the average degree of hyphal growth was positive and statistically significant. Regression of infection rate in short period (rs) on degree of hyphal growth in plant cell at the presumed infection time of newly formed lesions was also positive and significant. The extent to which the degree of resistance or susceptibility of rice plants contributes to variation of both infection rates is about 40%. The effects of the degree of resistance or susceptibility of plant on both infection rates, r and rs were different between years, showing that the influence of climatic factors on infection rate is very large.
    Download PDF (769K)
  • Minoru TAKAHASHI, Yutaka TANAKA, Takio ICHITANI, Romeo V. ALICBUSAN
    1972 Volume 38 Issue 4 Pages 306-312_2
    Published: September 01, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Several species of Pythium were isolated from damped off sugar beets and considered as the pathogens. Pythium betae n. sp. was identified as a new species. P. aphanidermatum (Edson) Fitz., P. spinosum Sawada, and Pythium spp. were also isolated. Sporangia of P. betae n. sp. are spherical, often oval. Germination is either by zoospores or by germ tube. Oogonia are rarely smooth, usually 2-3 spines, spherical, 14.3-21.3μ in diameter. Oospores filling the oogonium, rarely not filling. Antheridia one or two in an oogonium and attached at the lateral side.
    Download PDF (958K)
  • Takio Ichitani, Tomio Kometani, Minoru Takahashi
    1972 Volume 38 Issue 4 Pages 313-322_2
    Published: September 01, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Amakuri squash seedlings were cultivated in Hoagland solution in plant growth chamber, and water-soaked spots and spreading lesions were described on Pythium-infected hypocotyls when the seedlings were pre-treated with sodium diethyldithiocarbamate (NaDEDC) in relation to increase in host susceptibility. A slight abnormal elongation of the growth of the seedlings was found both in plant growth chamber and in water culture. Browning spots were formed in both soil and solution-grown seedlings after inoculation. The nutrient solution did not give any effect on the mycelial growth of the pathogen. The cell sap expressed from hypocotyls treated with NaDEDC did neither stimulate nor inhibit the fungal growth. Water-soaked lesions were found without any phytotoxicity when pre-treated with ether for 20-120 seconds. Only NaDEDC and sodium fluoride were considered good among the metabolic inhibitors used which induced water-soaked lesions because of the absence of phytotoxicity and stimulative effects on the fungal growth. Cuttings of the seedling which were supplied with the NaDEDC through their cut ends did not exhibit browning spots but rather formed water-soaked lesions. The water culture was more desirable method with NaDEDC than the injection in obtaining plant materials with water-soaked lesions.
    Download PDF (1181K)
  • Kiyoshi KIRIYAMA
    1972 Volume 38 Issue 4 Pages 323-332
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Tobacco leaf curl isolates were collected from tobacco fields throughout Japan. Diseased plants from southern Japan showed severe symptoms, whereas plants from northeastern Japan showed mild symptoms. Results of graft inoculation experiments in the green house showed that the difference in symptoms was dependent on environmental conditions, not on virus strains. Isolates from all areas developed similar symptoms under green house conditions. Sixteen new host species belonging to genus Nicotiana were found. These included N. knightiana, N. pauciflora and N. bigelovii. Several methods were tested in an attempt to transmit tobacco leaf curl virus (LCV) mechanically, but with no success.
    LCV was partially purified from the sap of infected tobacco leaves by butanol clarification and differential centrifugation. Purified preparations exhibited a single peak during analytical ultracentrifugation, and showed ultraviolet absorption maxima at 260mμ and minima at 238mμ. Negative stained virus preparations showed spherical particles approximately 30mμ in diameter under an electron microscope.
    Anti-LCV serum, titre 1/64, was obtained from rabbits injected with the purified virus preparations. Results of precipitin tests, agar diffusion tests and absorption tests between the anti-LCV serum and homologous and heterologous antigens, confirmed that the antiserum contained LCV specific antibodies. The usefulness of serological technique with non-sap transmissible virus is discussed.
    Download PDF (2573K)
  • Wen Chuan Wu
    1972 Volume 38 Issue 4 Pages 333-341
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Temperate phage PXC7 was isolated from smooth strain XCJ18 and propagated on smooth strain XCJ19 of Xanthomonas citri. It produced small turbid plaques with irregular borders. It was inactivated when heated at 77°C for 10min, exposed to chloroform for 1min, or irradiated under ultraviolet light (National GL-15) at the distance of 40cm for 75 seconds.
    When phage PXC7 lysogenized XCJ19, the genetic characteristics of this bacterium were modified by an alteration of colony types from smooth to dwarf. Reversion occurred in the lysogenic dwarf clones to produce smooth colonies. Some of these revertant clones were lysogenic and the others non-lysogenic, either resistant or sensitive to phage PXC7. Both lysogenic and resistant smooth revertants were incapable of adsorbing phage PXC7. The receptor sites for PXC7 were suggested to be same as to those for virulent phage CP2. Such a modification, therefore, may provide a safeguard in both lysogenic and resistant smooth revertants preventing lysis by CP2 infection. In connection with these modifications, both lysogenic and resistant smooth revertants grew some of their cells in the form of chains. All of these alterations had not been found with the sensitive smooth revertant. Both lysogenization and persistency with lysogeny or resistance were, therefore, concluded to be ressonsible for these alterations.
    The lysogenic dwarf convertant, after developing from its smooth original strain XCJ19, continued to liberate phage PXC7 spontaneously at the frequency considerably higher than its lysogenic smooth revertant. The resistant smooth revertant did not liberate the phage. They did so even after haing entered their susceptible host. As a result, the lysogenic dwarf convertant did not grow sufficiently to developving canker lesions as the lysogenic, resistant, and sensitive smooth revertants and smooth original strain XCJ19. Moreover, the lysogenic dwarf convertant also reverted in the leaf tissue in some of its cells to produce smooth colonies, which consisted of either lysogenic or sensitive cells.
    Download PDF (903K)
  • Sakari KATO, Tadao MISAMA
    1972 Volume 38 Issue 4 Pages 342-349
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Virus Invaded-cells in the infected tissues can be detected by measuring the DNA content in the nucleus. Making use of this assessment, spread of virus and metabolic changes in CMV inoculated tissue were studied.
    Most cells invaded by virus were located in the epidermal tissue during the first 4 hours after inoculation. Four hours after inoculation some of the palisade cells began to be invaded with virus and 8 hours later virus-invaded cells were seen in the spongy parenchyma. Virus reached to the opposite epidermal cells as early as about 12 hours. However, an increase in the number of virus-invaded cells ceased about 36 hours after inoculation and subsequently the speed on the multiplication of virus began to increase.
    In CMV inoculated tissue, an increase in respiratory rate occurred immediately after inoculation. This increase in respiration was due to the increase in the number of virus-invaded cell and seemed not to be due to the increase of virus synthesis in the tissue. Namely, even in the prime of virus synthesis, energy required for virus synthesis is not so large as to induce changes of respiration.
    The changes of enzymatic activity in virus-invaded cells can be expressed by the equation derived from “Infected cell ratio” and enzymatic activity in the tissue. With the aid of this equation it is possible to detect even a subtle change in host metabolism in the early stages of infection and to estimate net metabolic change in virus-invaded cells. As determined by using this equation, peroxidase activity showed rapid increase immediately after inoculation but 4 hours later it returned to control level and thereafter maintained its level. This finding was in contrast with that obtained by ordinary method.
    A marked increase of peroxidase activity was seen at the time when the infection was confined to epidermal tissue but not seen in other infected areas.
    Polyphenol oxidase activity, however, decreased markedly during the first 2 hours after inoculation and thereafter increased gradually. It is conceivable that this initial decreased of enzymatic activity is due to the decrease of enzymatic activity in both cells invaded by virus and adjacent cells of it.
    Making use the calculation of “Infected cell ratio” as well as the equation derived from “Infected cell ratio” and enzymatic activity in the tissue, the accurate analysis of metabolic changes that take place in host cells invaded with virus was thus possible.
    Download PDF (1048K)
  • Tadaaki HIBI, Kiyoshi YORA
    1972 Volume 38 Issue 4 Pages 350-356_4
    Published: September 01, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Isolated protoplasts from tobacco mesophyll tissues were inoculated with tobacco mosaic virus (TMV), and the process of TMV infection in the protoplasts was observed by electron microscope at various times after inoculation. TMV particles attached to the cell membrane with their particle ends immediately after inoculation. And an average of 10-102 virus particles per protoplast was taken up by phagocytosis within 10 minutes after inoculation. By 30 minutes, 46% of virions which had been taken up into the protoplast disappeared from the phagosomes and this value rose to 72% after 6 hours. Virus particles were first seen in the ground cytoplasm after 9-12 hours as individuals or small aggregates, and after 48 hours, a level of 106 virus particles per protoplast appeared as semi-crystalline aggregates in the ground cytoplasm. Specific morphological changes of nuclei, chloroplasts and mitochondria resulting from the virus infection were not observed and no virus particles were seen in these subcellular organelles till 48 hours after inoculation.
    Download PDF (3947K)
  • Hitoshi KUNOH
    1972 Volume 38 Issue 4 Pages 357-358_1
    Published: September 01, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Download PDF (582K)
  • Natsuki NISHIHARA
    1972 Volume 38 Issue 4 Pages 359-361
    Published: September 01, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (846K)
  • 1972 Volume 38 Issue 4 Pages 362a
    Published: 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (103K)
  • 1972 Volume 38 Issue 4 Pages 362b
    Published: 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (103K)
  • 1972 Volume 38 Issue 4 Pages 362c
    Published: 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (103K)
feedback
Top