Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 39 , Issue 1
Showing 1-17 articles out of 17 articles from the selected issue
  • Naoji SUZUKI, Ikuo KIMURA, Tadashi KODAMA
    1973 Volume 39 Issue 1 Pages 1-6
    Published: January 01, 1973
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    It has already been reported that rice dwarf virus (RDV) contains double-stranded RNA and that RDV-RNA is easily separated from host cell nucleic acids by methylated albumine-kieselguhr column chromatography and also by cellulose column chromatography. These procedures make it possible to screen such substances which inhibit the incorporation of 32P into RDV-RNA but do not inhibit the 32P-incorporation into ribosomal RNA (rRNA). Two grams of uppermost and second leaves detached from RDV-infected rice plants were placed in a test tube containing 2ml of aqueous solution of an antibiotic and 60μc of 32P-H3PO4 and kept under greenhouse conditions. After whole the solution was almost absorbed by the leaf sample, 3ml of water was added to the tube. After 24 hours, nucleic acid was extracted by phenol method and one fourth of the nucleic acid preparation was subjected to cellulose column chromatography. Optical densities at 260nm of rRNA and RDV-RNA and radioactivities of both RNA's were measured. Inhibitory effect of an antibiotic for the syntheses of both RNA's was evaluated by the decrease of cpm/OD260 values. Cycloheximide at 2μg/g fresh weight inhibited the incorporation of 32P into both rRNA and RDV-RNA equally suggesting that the antibiotic is phytotoxic. This was indeed the case when the antibiotic was applied to RDV-infected rice plants at 2ppm through culture solution, i.e., the plants died within 2 weeks. Blasticidin S at 3μg/g and kasugamycin at 160μg/g fresh weight rather stimulated the 32P-incorporation into both rRNA and RDV-RNA, whereas at higher dosages, 6μg/g and 320μg/g respectively, they inhibited the 32P-incorporation into both RNA's but only very slightly. When these were applied to infected plants through culture solutions at liminal concentrations, i.e., 2 and 40ppm respectively, throughout the whole life period, there was no sign of the recovery of normal growth.
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  • Toshikazu TANI, Masaaki YOSHIKAWA, Nakato NAITO
    1973 Volume 39 Issue 1 Pages 7-13
    Published: January 01, 1973
    Released: February 19, 2009
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    Ribonucleic acid extracted from oat primary leaves led to incorporation of 14C-phenylalanine into acid insoluble fractions in E. coli cell free systems containing Mg2+, ATP, and an ATP regenerating system. The rate of incorporation was about one-tenth of that directed by poly-U and was inhibited by chloramphenicol and ribonuclease. Using this system, changes in messenger RNA activity were followed in oat leaves infected with Puccinia coronata. In Victoria, a susceptible variety, the template activity did not change during the vegetative growth stage of the fungus (1 and 2 days after inoculation), but it increased 1.4-fold of noninoculated control leaves at the initiation of uredosorus formation (4 days after inoculation). In Shokan 1, a resistant variety, no significant difference in messenger RNA activity was detected between the inoculated and noninoculated leaves, despite increased synthesis of total RNA in the inoculated, resistant responding leaves. The resistant response, therefore, did not appear to involve quantitative changes in messenger RNA levels.
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  • Osamu HORINO
    1973 Volume 39 Issue 1 Pages 14-26_3
    Published: January 01, 1973
    Released: April 03, 2009
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    Ultrastructure of Xanthomonas oryzae cultured on a medium, the degeneration process of the cultured bacteria induced by chemical treatment, and the ultrastructural changes of the bacteria growing in rice plants by the chemical treatment were studied using a streptomycin-resistant strain.
    The bacterium is surrounded by a relatively electron-transparent cell wall, and a cytoplasmic membrane composed of a continuous unit membrane is present along the inside of this cell wall. Nuclear material of fibrillar appearance, ribosomes, polysomelike structures and two kinds of granules of different components were observed in the cytoplasm. Mitochondria, endoplasmic reticula, and mesosomes were not observed in the cytoplasm. Particles which seemed to be polysomes occurred occasionally in the cytoplasm. Granules of high electron density which appeared to be a certain kind of lipid and some of low density were observed in the cytoplasm.
    Bacteria taken from the peripheral region of the inhibition zone induced by 2-amino-1, 3, 4-thiadiazole (ATDA) were examined. The electron density of cytoplasm decreased and few ribosomes were present. The coagulation of the cytoplasm caused irregular lysogenous spaces with no boundary. On the other hand, it was observed that the cytoplasm aggregated in a certain region and developed into a spherical body which was enclosed within 20-40nm in thick wall. Such bodies were observed only in the bacteria at the peripheral region of the inhibition zone. The spherical body was enclosed by an electron-dense outer layer and an electron-transparent inner layer, and was filled with electron-dense material. The above observations of the body are consistent with the ultrastructure of spore. The author temporarily termed it sporelike structure. In the bacteria taken from the central region of the inhibition zone, fibrillar structure coagulated and then disappeared.
    In the vessels of rice plants treated with ATDA, especially the bacteria in pitted vessels showed drastic degeneration. Their cell wall and cytoplasmic membrane collapsed, resulting in the flowing out of the cytoplasm. On the other hand, the bacteria in spiral and ring vessels did not show any prominent change in their cell organelles. Such a difference probably depends on the quantitative difference of ATDA in those vessel types.
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  • Tetsuo TAMADA
    1973 Volume 39 Issue 1 Pages 27-34_2
    Published: January 01, 1973
    Released: April 03, 2009
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    Isolates of soybean dwarf virus (SDV) obtained from naturally infected plants were divided into two groups on the basis of their symptoms on soybean plants. One group was designated as a dwarfing strain, which caused a dwarfing of plants with shortened petioles and internodes. Another group was designated as a yellowing strain, which caused a slight chlorosis of leaflets and interveinal yellowing of older leaves. In the field, soybean, pea, and white (Ladino) clover plants were found to be infected with both strains, whereas bean plants were infected only with the yellowing strain and red clover only with the dwarfing strain.
    Three isolates, SDV-DS (caused severe symptom) and SDV-DM (mild symptom) belonging to the dwarfing strain, and SDV-Y belonging to the yellowing strain, were used here as virus sources. Of 28 leguminous species inoculated by the aphid Aulacorthum solani (Kaltenbach), 13 species became infected with SDV-DS and 16 species with SDV-Y. In general, the symptoms caused by SDV-Y were more severe than those caused by SDV-DS on many infected plants: stunting, chlorosis, and interveinal yellowing or marginal reddening of older leaves. The mode of transmission of SDV-Y was quite similar to that of SDV-DS.
    When soybean plants were inoculated simultaneously with SDV-Y and SDV-DS or SDV-DM, the infected plants usually developed the symptoms more severe than those caused by either virus isolate alone, showing a marked rugosity of leaflets and a severely stunting of plants. Plants infected doubly with SDV-DS and SDV-DM showed the intermediate symptoms between these. Mixtures of these isolates could be separated by single aphid transfer to soybean plants. Soybean plants infected already with SDV-Y were not protected against infection with SDV-DS or SDV-DM, although the symptom development of SDV-DS or SDV-DM was delayed. Similarly, SDV-DS or SDV-DM also gave no protection against SDV-Y. However, SDV-DS and SDV-DM could protect against each other in soybean plants.
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  • Iwasaburo GOTO
    1973 Volume 39 Issue 1 Pages 35-41
    Published: January 01, 1973
    Released: February 19, 2009
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    In the blast disease of rice plants, there were two ways to record the relationships between host and pathogen. The one was qualitative, assigning the varietal reactions in a few class judging from lesion types by the spraying or injection method14), and the other was quantitative, estimating their susceptibility indicies which indicated the hyphal development in cells of host by the sheath inoculation method. The conclusions drawn by the factor analysis from quantitative records were consistent with the ones of qualitative data as previously reported by Morishima16) as follows: (1) The contribution of the first component of the races or of the isolates was distinctly much more than those of the second or of other higher ones. (2) The first component score was found to be closely correlated to the general resistance score or to the average degree of resistance of varieties.
    Of twenty-four races scattered by the first and second factor, T, C-1, C-2 and C-5 Races were differentiated from N-Races on the one side, increasing the number of varieties susceptible, and on the other C-3 and C-6 Races, specializing their varietal reactions. Culculating from the susceptibility indicies, those distinguishable differences were observed in the magnitude of the loading of the first component between the varieties grouped into the same presumed genotype, qualitatively designated from lesion types. Those differences were confirmed to be based on the genic systems of varieties, for instance, that of the Sensho4) and the Norin No.2213), of the Shin-No.2 type.
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  • Hitoshi KUNOH, Hiroshi ISHIZAKI
    1973 Volume 39 Issue 1 Pages 42-48_4
    Published: January 01, 1973
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    It was observed using an electron microscope that the mitochondria of Hordeum vulgare L. were incorporated into the encapsulation of Erysiphe graminis hordei. The host mitochondria aggregated in the cytoplasm near the haustorial lobes. Some of them were in contact with the encapsulation membrane and in some cases, segments of the encapsulation membranes were elongated towards the mitochondria and joined them. At the contact phase the mitochondrial outer membrane disappeared, and the cristae and matrix directly contacted the encapsulation matrix. The mitochondria appeared to be incorporated into the encapsulation with subsequent degradation of the cristae into their units. The degraded cristae units were found along the encapsulation membrane, or they were released in the encapsulation matrix. A double mitochondrial membrane continuing to the encapsulation's single membrane was clearly discernible at the contact point of the encapsulation and the host mitochondria.
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  • Yasushi YASUDA, Sho HASHIMOTO, Yoshinori SOEDA, Teruhisa NOGUCHI
    1973 Volume 39 Issue 1 Pages 49-52
    Published: January 01, 1973
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Thiophanate-methyl (Th-M) was metabolized by Pellicularia sasakii and Alternaria mali which have some difference in sensitivity to this fungicide, and its main metabolite was identified as methyl 2-benzimidazolecarbamate (MBC). As minor metabolites, methyl 5-hydroxy-2-benzimidazolecarbamate (HMBC) and an unknown substance (X) were also found in the incubated solution.
    The similar metabolic products of Th-M were obtained by the fungi, with the exception of X which was formed only by a sensitive fungus, P. sasakii. However, the formation of MBC and HMBC by an insensitive fungus, A. mali was more rapid than those by P. sasakii. The antifungal activity of MBC against P. sasakii was more effective than that of Th-M or HMBC. Mycelial growth of A. mali was scarcely inhibited by MBC and HMBC.
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  • Yasuo SONKU, Yoshiro SAKURAI
    1973 Volume 39 Issue 1 Pages 53-60_1
    Published: January 01, 1973
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Microscopic examination of salivary sheaths, which were produced as stylet tracks by allowing small brown planthopper, Laodelphax striatellus Fallén, to feed on agar film, revealed that the salivary sheath is generally shaped like a sword and varies in length and in number of branches according to instars and adult sex of the hopper tested. Observation on point of feeding and path of penetration in rice leaf, differentially stained by erythrosine, indicated that the hoppers prefer the veins and paths of the inserted stylets direct mostly toward the vascular tissue. Furtheron the access of salivary sheaths to sieve tube and to vessel were in the ratio of 73 to 27 in leaf blade and 67 to 33 in leaf sheath, respectively. Thus the stylet punctures by small brown planthopper are found to terminate mostly in vascular bundles, particularly in phloem, accompanied with several branchings. The hoppers formed far less stylet tracks on the epidermis of leaf sheath in stripe-resistant varieties than in susceptible varieties. From living or frozen pieces of leaf sheath on which viruliferous hoppers had been fed for 1 to 6 hours, another species of planthopper. Unkanodes albifascia Matsumura, featuring outstanding compatibility with stripe virus, could recover the virus. Equality in heat-stability of the virus given off from viruliferous hoppers with that in diseased leaf blade and other evidence suggest that the virus is of protein coated.
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  • Satoshi TANAKA, Hiroyuki SHIOTA
    1973 Volume 39 Issue 1 Pages 61-66_2
    Published: January 01, 1973
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Physalis floridana and Datura stramonium plants were inoculated with potato leaf roll virus by using viruliferous green peach aphids (Myzus persicae), and at various intervals after the inoculation, virus recovery tests were made by using non-viruliferous aphids. The earliest recovery time from upper leaves, inoculated leaves and lower leaves was 2-4, 0-2 and 6-8 days, respectively, after inoculation. Percentage of virus recovery was highest in upper leaves after 2 days following inoculation.
    Symptoms appeared on 6-7th day after inoculation in upper leaves and on 10-12th day in other leaves.
    Ultrathin sections of leaflet midrib tissues of these plants were examined by an electron microscope. Necroses were observed in phloem cells of upper and inoculated leaves 5 days after inoculation. In samples of 10-15 days after inoculation, the number of necrotic cells was approximately three times of that in samples of 5 days after inoculation.
    There were two types in necroses observed in the phloem: coagulation or disintegration of cytoplasm (DC type) and reticulate or fibrous structures in cytoplasm (NC type). DC type cells were observed more frequently in upper leaves than in lower ones in earlier period after inoculation. NC type cells were seen more frequently in lower leaves than in upper ones in later period after inoculation. The fibrous structures were recognized also in necrotic cells of healthy plants.
    Virus particles were observed within DC and NC type cells with reticulate structres, but not in NC type cells with fibrous structures.
    The following time sequence is suggested: virus multiplication→phloem necrosis→external symptoms.
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  • Tsuneo TSUCHIZAKI
    1973 Volume 39 Issue 1 Pages 67-72_1
    Published: January 01, 1973
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Four kinds of viruses were isolated from beans showing mosaic symptoms collected from Fukushima prefecture. These were cucumber mosaic virus (CMV), bean common mosaic virus, bean yellow mosaic virus, and a virus previously unreported in Japan. The virus was transmitted by sap and by at least two species of aphids. Host range of the virus was moderatly wide, mostly in Leguminosae and Solanaceae. In bean or tobacco juice, infectivity was lost by heating at 55-65C for 10 minutes, and by aging at 15C for 5 to 10 days, and by diluting at 103-104. The virus was purified after clarification of homogenized tobacco leaf tissues with chloroform, by differential centrifugation followed by sucrose density-gradient centrifugation. Electron microscopic examination of purified preparation showed spherical particles of 25-30nm in diameter. In the serological test, this virus was closely related with peanut stunt virus (PSV), and was distantly related to chrysanthemum mild mottle virus. Antiserum to the virus did not react with Y strain of CMV and two strains of broad bean wilt virus. From these results, this virus was identified as a strain of PSV and I proposed the name of PSV-J for Japanese isolate. This is the first report in occurrence of PSV in other countries than America.
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  • Kohei TOMIYAMA
    1973 Volume 39 Issue 1 Pages 73-78
    Published: January 01, 1973
    Released: February 19, 2009
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    The process of hypersensitive death of a potato cell infected by an incompatible race of Phytophthora infestans was observed by using a temperature controlled, inverted microscope. More precise observation than in previous experiments disclosed that the process of hypersensitive death of the cells consisted of at least two phases: cessation of protoplasmic streaming and then loss of stainability of vacuole with neutral red. The infected cell still maintained stainability with neutral red and could absorb it after the protoplasmic streaming stopped. After a while, the cell lost the stainability with neutral red. The effect of temperature on this process was investigated. The time elapsed from inoculation to the penetration was longer at 20C than at 25 and 30C.
    By extraporating the growth curve of the intracellular hyphae to O, length of the penetration was judged to finish 10-15min before the hyphae become actually visible, so that the time required for hypersensitive cell death is longer than that estimated in prlor experiments.
    In 10-20% of the cut surface cells inoculated 18hr after cutting, protoplasmic streaming stopped about 30min after penetration (at 20, 25 and 30C) and in 50% of the cells protoplasmic streaming stopped about 37min (20C) 40min (25C) and 45min (30C) after penetration. The cells seemed to lose their stainability with neutral red about 30min (20C), 10min (25C) and 10min (30C) after protoplasmic streaming stopped.
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  • Tadao MISAWA, Eiichiro MIYAZAKI
    1973 Volume 39 Issue 1 Pages 79-80
    Published: January 01, 1973
    Released: February 19, 2009
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  • Yuko OHASHI, Toru SHIMOMURA
    1973 Volume 39 Issue 1 Pages 81-82_1
    Published: January 01, 1973
    Released: April 03, 2009
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  • 1973 Volume 39 Issue 1 Pages 84a
    Published: 1973
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1973 Volume 39 Issue 1 Pages 84b
    Published: 1973
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1973 Volume 39 Issue 1 Pages 84c
    Published: 1973
    Released: February 19, 2009
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  • 1973 Volume 39 Issue 1 Pages 84d
    Published: 1973
    Released: February 19, 2009
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