Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 55 , Issue 2
Showing 1-20 articles out of 20 articles from the selected issue
  • Yasuo HOMMA, Hiroharu TAKAHASHI, Yutaka ARIMOTO
    1989 Volume 55 Issue 2 Pages 131-139
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    When satsuma mandarin fruits on trees were inoculated with Diaporthe citri to their pedicels, then harvested and stored in the condition of room temperature, stem-end rot was observed on almost all the fruits at the late stage of storage. Despite hyphal penetration and elongation to the pedicel or into pedicel-end core, there was no hyphal existence between the disks and the tissues underneath where a lot of needle-like crystals were distributed. Solutions of the crude crystals at 462∼4, 620 fold dilutions showed inhibitory activity against the fungus, and higher concentration of the crystals exhibited stronger inhibition to the hyphal elongation. Though the crystals were not observed in pedicel-end of young fruits, many of them were distributed after October when they became matured. Since the crystals did not exist in the stemend at the end of storage, we assumed that they had disappeared by self-digestion of citrus fruit. A similar inclination on the antifungal activities was already observed in fruit vesicle extract. Similar crystals were also observed in the vascular bundle systems in fruit core and leaves, especially in adult leaves.
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  • Mitsuro HYAKUMACHI, Akio SUMINO, Yoshihisa HOMMA
    1989 Volume 55 Issue 2 Pages 140-147
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Occurrence or disappearance of abnormality in normal or abnormal isolates of Rhizoctonia solani anastomosis group 4 (AG4) by several treatments were examined. Abnormality has not disappeared by heat (40∼60C) treatment, chemical (streptomycin sulfate, oxytetracycline, chloramphenicol, cycloheximide, ethidium bromide, acriflavine) treatment, hyphal tip or mass transfer, and single protoplast isolation of abnormal isolates. On the other hand, abnormal isolates occurred from healthy isolates by single protoplast isolation and hyphal tip transfer with low frequency of 0.9% and 0.2%, respectively. These results showed that agent(s) stimulating abnormality had already existed in healthy isolates. Development of abnormality was also highly seen when normal isolates were dipped into a culture broth or macerated suspension of abnormal isolates. However, it was not seen in the case of a culture broth or macerated suspension filtrated through membrane (0.45μm). Lethal isolates which produced brown-black pigment in medium and could not survive after transfer were obtained both from normal and abnormal isolates. Besides agent(s) stimulating abnormality, the existence of lethal agent(s) has been suggested.
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  • Hidetoshi UEKUSA, Yasuo SUGASAWA, Tohru TERAOKA, Daijiro HOSOKAWA, Min ...
    1989 Volume 55 Issue 2 Pages 148-155
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The effect of metabolic inhibitors on multiplication and distribution of tobacco mosaic virus (TMV) and cucumber green mottle mosaic virus (CGMMV) in cucumber cotyledons was investigated. The amount of TMV, as assayed by ELISA, increased about 8 times in cucumber cotyledon when actinomycin D (3μg/ml) was applied immediately or at 1 day after inoculation, but not increased by the application at 2 or 3 days after inoculation. TMV also increased to 3-fold when rifampicin (100μg/ml) was applied just after inoculation. These antibiotics had no significant effect on CGMMV multiplication in cucumber cotyledons. The area of TMV distribution in cucumber cotyledons was researched using the fluorescent antibody technique. TMV was observed in limited areas of the epidermal and palisade layers when cotyledons were treated with water. When cotyledons were treated with actinomycin D, however, TMV multiplied and spread horizontally and vertically in the tissues, and infected cells were observed in the upper epidermal, palisade, spongy parenchyma and also lower epidermal layers. These results revealed that actinomycin D increased TMV concentration in consequence of the spread of infected areas by inhibiting localization of the virus.
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  • Henry NELSON, Tomonori SHIRAISHI, Hachiro OKU
    1989 Volume 55 Issue 2 Pages 156-160
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The abaxial epidermis of the primary leaf of one cultivar of barley was stripped off and exchanged with that of another cultivar. A comparison was made of the 48-hr infection frequency of powdery mildew on the various combinations of composite leaf sections in an attempt to determine the respective roles of the epidermis and mesophyll in the resistance of barley to powdery mildew. In the case in which resistance was clearly defined, the results suggested that the resistance reaction occurs mainly in the epidermis. While the mesophyll appears to play a supportive role in the resistance mechanism, it is also possible that the mesophyll contains a factor which can act to promote powdery mildew infection.
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  • Hideki TAKAHASHI
    1989 Volume 55 Issue 2 Pages 161-169
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Radish enation mosaic virus (RMV) is a member of the comovirus group, but a biochemical characterization of the group has been done only with cowpea mosaic virus (CpMV) which is the type member of the group. Therefore, the biochemical properties of other members of the group, such as RMV, are poorly understood. The present study was an attempt to analyze the nucleic acid, coat protein and gene composition of RMV. The purified RMV was fractionated into the three components (T, M and B components). B and M components were composed of two kinds of coat proteins with molecular weights of 47k and 18k daltons and contained single stranded RNAs with molecular weights of 2.0×106 and 1.6×106 daltons respectively, but T did not contain RNAs. The RNAs contained poly (A) sequences. Then, the B-RNA was in vitro translated into one polypeptide with a molecular weight of 200k daltons in the presence of zinc ions, which inhibited the protease activity. M-RNA was in vitro translated into two polypeptides with molecular weights of 115k and 105k daltons. These products in vitro translated from M and B-RNA were cleaved into eight kinds of polypeptides during incubation without the zinc ions. The results indicated that RMV might have essentially the same chemical composition and translation strategy as cowpea mosaic virus, except that the molecular weights of M-RNA and M-RNA translation products of RMV were quite different from those of CpMV.
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  • Keiko KURODA
    1989 Volume 55 Issue 2 Pages 170-178
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Following invasion by the pine wood nematode, Bursaphelenchus xylophilus, cavitation develops in the sapwood of Pinus thunbergii. This causes abnormal water conduction in the trunk, and is supposed to result in death of infected trees. Cavitation, assumed to be vapor blockage, can be induced by gas produced inside the tree without induction of air from outside. To detect the substances causing cavitation, constituents of vapor in the cavitation areas were analyzed by gas chromatography using xylem harvested 2 weeks after the inoculation with pine wood nematode. Amount of mono- and sesquiterpenes increased significantly in the nematodeinoculated sample: α-pinene was 2 to 4 times that of healthy tree, β-pinene and several other monoterpenes 2 to 3 times, and longiforene, a sesquiterpene, ca. 3 times. Terpene synthesis seemed to be activated before development of cavitation. Monoterpenes excessively produced and exuded in tracheids will vaporize easily under negative pressure in summer months, and will disrupt water columns of the tracheids throughout wide areas within short time. Even when water stress is reduced during night or in autumn, refilling of tracheids with water will be prevented by hydrophobic terpenoids. It is proposed that the vapor blockage of tracheids caused by evaporating terpenoids is responsible for extensive cavitation in pine sapwood within a short period after the invasion of pine wood nematode, and pine trees are eventually killed by water deficit following the cavitation.
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  • Yoshiyuki TAKAHASHI, Mitsuro KAMEYA-IWAKI, Ken-ichiro SHOHARA
    1989 Volume 55 Issue 2 Pages 179-186
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Eleven murine monoclonal antibodies (MABs) specific for L11A, a tomato strain of tobacco mosaic virus (TMV-L11A), were produced in culture supernatants and in ascitic fluids. Reactivities of all the 11MABs with tobamovirus strains were investigated by two indirect ELISA procedures, competitive ELISA, precipitin ring interface test and immuno-double-diffusion test. Five MABs among them reacted only with tomato strains (L11A, L and CH2) and the others reacted not only with tomato strains but also with other strains [TMV-OM, P, W and cucumber strain of cucumber green mottle mosaic virus (CGMMV-Cu)]. Based on these results, at least eight epitopes were distinguished on the surface of the particles of L11A. The epitopes, except for one detected by one of the MABs (6F11), were all neotopes, and 10 out of 11MABs were anti-neotope antibodies including a heterospecific antibody (8C8). A superior epitope which reacted mainly in the antiserum was identified within these epitopes. The high specificity of the MABs showed that they were useful for the differentiation of tobamovirus strains. The titers of three MABs in ascitic fluids were 1:2, 560 and they could be substituted for rabbit antisera. This study showed that the antigenic specificity of the strains was mainly dependent on the neotopes.
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  • Daijiro HOSOKAWA, Minoru WATANABE, Kanichi MORI
    1989 Volume 55 Issue 2 Pages 187-193
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Leaf ontogeny and virus multiplication in tobacco plants systemically infected with tobacco mosaic virus were investigated using a fluorescent antibody technique to know the origin of mosaic symptoms. Leaf primordium was initiated at the apical meristem where virus antigen was not detected, and contained no virus antigen in the early stages of development. Virus infection was first detected in the phloem after the vascular bundle had differentiated in the leaf primordium and thereafter spread to the lamina. Areas where no virus antigen was found, were produced near the midvein, secondary veins and tertiary veins during leaf development, while abundant virus multiplication occurred in other areas. In the course of mosaic symptom development, dark green areas arose from the areas where no virus antigen was found, and yellow green areas resulted from the areas where the virus multiplied abundantly. In the dark green areas, most cells contained no virus antigen for weeks. after the leaves had fully expanded, although infection was noted in a small number of cell groups. In contrast, no mosaic symptoms appeared in leaves which had fully expanded at the time the plant was inoculated although the virus antigen was found in all parts of the leaf tissues. These results suggested that the occurrence of dark green areas is related to the histogenesis of areas near the leaf veins.
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  • Daijiro HOSOKAWA, Minoru WATANABE, Kanichi MORI
    1989 Volume 55 Issue 2 Pages 194-200
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The multiplication and distribution of tobacco mosaic virus in Nicotiana tabacum cv. Samsun NN leaves were investigated using the fluorescent antibody technique, in relation to the local lesion development. Virus antigen was first detected 24hr after inoculation in cell groups in the epidermal and palisade layers as well as in a few cells of spongy layer. Thereafter, progressive cell-to-cell spread of the antigen in leaf tissues was observed, and 32hr after inoculation, the stained areas were in the form of a cell group extending from the upper epidermal to the lower epidermal layer. By this time the virus antigen was also found in phloem cells, suggesting that virus long distance movement had begun. Necrosis was discovered in one or two cells of the upper spongy layer located in the central part of the stained areas 36hr after inoculation. Thereafter, cell necrosis spread rapidly in the spongy layer, and then in the palisade layer and upper and lower epidermis. When local lesions became visible 44hr after inoculation, necrosis had already spread throughout the greater part of the stained area. However, a few cells bordering the lesions contained the virus antigen and had no necrosis. Thereafter, continuous cells become progressively infected and necrosis developed into the inner cells, increasing the size of the local lesions. In N. tabacum cv. Samsun, the progressive spreading pattern of the virus antigen was similar to that of N. tabacum cv. Samsun NN until cell necrosis first appeared in the latter.
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  • Takahito NODA, Akira OHUCHI
    1989 Volume 55 Issue 2 Pages 201-207
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Many isolates of Xanthomonas campestris pv. oryzae collected from various districts of Japan in 1985 were tested for their virulence to the differential rice varieties. Two isolates of X. campestris pv. oryzae, H8581 and H8584, collected from Miyazaki Prefecture, showed a new virulence pattern different from known races. These two isolates were tested again to determine their virulence to many rice varieties of each varietal group. They were virulent to Kinmaze group rice varieties except for IR 24 and Milyang 23, to about half of all Kogyoku group varieties, and to Wase Aikoku and Java group varieties. On the other hand, these isolates were not virulent to the above two varieties of the Kinmaze group, Rantai Emas group and IRRI varieties and the other Kogyoku group varieties. We therefore proposed that these new pathogenic isolates, H8581 and H8584, should be hereafter designated as race VII. The resistance of rice variety Te-tep belonging to Rantai Emas group to race VII was governed by two dominant genes. The one of them was allelic to the known gene for race II, Xa-2, or linked very closely with it, while another was independent of the known resistant genes, Xa-1 and Xa-2. We also proposed that the latter dominant gene found in Te-tep should be designated as Xa-16. However, it will be necessary for further detailed studies on the former resistance gene for race VII.
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  • Chiyoichi NODA, Narinobu INOUYE
    1989 Volume 55 Issue 2 Pages 208-215
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A potyvirus isolated from an ornamental Allium ampeloprasum cv. ‘Murasame’ showing mosaic and white necrosis on the leaves, collected in Kurashiki, was identified as an isolate of leek yellow stripe virus (LYSV). LYSV was transmitted by aphids, Myzus persicae and Aphis gossypii, in a non-persistent manner and by sap-inoculation to 6 of 49 species from 4 of 11 families. A. ampeloprasum cv. ‘Miyako’ and A. giganteum were infected systemically and produced mosaic symptoms on leaves. Local lesions were produced on Chenopodium amaranticolor and C. quinoa, whereas systemic latent infection was produced on Spinacia oleracea and latent local infection was on Gomphrena globosa. Sap from the diseased C. quinoa was infective after 10min heating at 50C but not 55C, after dilution to 10-3 but not 10-4 and after 4 days but not 8 days at 20C. The virus particles were filamentous, about 820nm long. The virus was purified from locally infected C. quinoa leaves by clarifying sap extracted in 0.5M phosphate buffer with chloroform/carbon tetrachloride mixture followed by PEG precipitation, differential centrifugations through sucrose cushion and sucrose density gradient centrifugation. LYSV contained a single protein species of mol. wt. 36, 500 daltons. In ultrathin sections of the virusinfected C. quinoa leaves, cytoplasmic inclusions containing pinwheels, scrolls and short curved laminated aggregates were observed in the cytoplasms. LYSV reacted with LYSV antiserum donated from Ir.D.Z. Maat (the Netherlands) and the antiserum to LYSV produced by immunizing a rabbit (titer: 1/512), but not with antisera to bean yellow mosaic virus, clover yellow vein virus, freesia mosaic virus, iris mild mosaic virus, iris severe mosaic virus, narcissus yellow streak virus, onion yellow dwarf virus, turnip mosaic virus and potato virus Y.
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  • Shiro KUNINAGA, Ryozo YOKOSAWA
    1989 Volume 55 Issue 2 Pages 216-223
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Genetic relatedness among 18 formae speciales within Fusarium oxysporum was determined on the basis of DNA-DNA reassociation kinetics. DNA homology values were high (more than 95%) between isolates within the same forma specialis, while isolates of different formae speciales showed lower values (63 to 86%) of DNA homology. Comparatively high homology values (90 to 95%) were observed within isolates of different formae speciales causing disease on the Cruciferae or the Cucurbitaceae plants. Isolates of F. oxysporum consistently showed low homology values (36 to 48%) with isolates of F. solani. These results suggest that formae speciales of F. oxysporum can be differentiated genetically from each other, indicating that the reassociation analysis of DNA may be a useful tool in studies involving classification and phylogeny of subspecific taxa in this species.
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  • Hideo TABEI, Koji AZEGAMI, Tokuji FUKUDA, Takao GOTO
    1989 Volume 55 Issue 2 Pages 224-228
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The causal bacterium of rice grain rot entered to the lemmata and paleae through the stomata, and multiplied in the intercellular spaces of the parenchyma. Stomata are mainly opened on the inner surfaces of lemmata and paleae, a few on outer surfaces of lemmata and they are connected each others through the intercellular space of parenchyma. The bacteria multiplied on the surface of albumen and embryo, but never invaded them.
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  • Yoshitaka KOSAKA, Kaoru HANADA, Tsutomu FUKUNISHI, Hiroshi TOCHIHARA
    1989 Volume 55 Issue 2 Pages 229-232
    Published: April 20, 1989
    Released: February 19, 2009
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  • Susumu TAKAMATSU
    1989 Volume 55 Issue 2 Pages 233-237
    Published: April 20, 1989
    Released: February 19, 2009
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  • Reiko SHIGEMOTO, Tetsuro OKUNO, Kazuho MATSUURA
    1989 Volume 55 Issue 2 Pages 238-241
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Tokuji KAGIWATA, Keiko T. NATSUAKI, Hiroshi FUJII, Hideo MUKOO
    1989 Volume 55 Issue 2 Pages 242-244
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Bacterial blight of lilac (Syringa vulgaris L.) was found in Nagano Pref., Japan. The disease first appears on shoot as water-soaked small spot. Those spots rapidly enlarge in size and become sunken, blackish and elliptical lesions. The lesions usually elongate longitudinally to form irregular-shaped stripes. Affected young shoots bend over at the lesions, wither and often die. The pathogenic bacterial isolates were identified as Pseudomonas syringae pv. syringae van Hall 1902 from the results of pathogenicity and bateriological tests.
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  • Satoshi T. OHKI, Nobuyuki YOSHIKAWA, Narinobu INOUYE, Tadao INOUYE
    1989 Volume 55 Issue 2 Pages 245-249
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Seisaku UMEMOTO, Akio MURATA, Yuji NAGAI
    1989 Volume 55 Issue 2 Pages 250-253
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Occurrence of Japanese pear rust on Japanese pear trees planted in the flat and extensive rice field (about 5km×4km) was generally severe in the area within 100m away from the infected trees of Chinese juniper as rust inoculum and gradually decreased with increase of distance up to 1, 500m. Under the climatically satisfactory condition to dispersal of sporidia such as heavy rainfall and strong wind, the trees planted within 1, 000m were rather severely diseased. The following relationships were detected between the distance of sporidial dispersal (x) and the percentage of diseased leaves (Y):Y=124.297e-0.002x in 1977, and Y=54.361e-0.002x in 1979. Therefore, it is concluded that the distance of sporidial dispersal for practical control may be about 1, 500m.
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  • Takeshi NISHIO, Akira KAWAI, Tsutomu TAKAHASHI, Shigetou NAMBA, Shuich ...
    1989 Volume 55 Issue 2 Pages 254-258
    Published: April 20, 1989
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Citrus tatter leaf virus (CTLV) was purified by molecular permeation chromatography on controlled pore glass beads after preliminary partial purification from infected leaves of Chenopodium quinoa. CTLV had very flexuous filamentous particles 600 to 650nm long and 13nm wide. In uranyl acetate, the particles were constructed with a pitch of 3.4nm and showed two types of fine structure, cross-banding and criss-cross pattern. The virus had a single RNA species with a mol. wt. of 2.83×106 and produced a single protein band (mol. wt. 27, 000) in SDS-PAGE. CTLV showed a serological relationship to apple stem grooving virus which is a member of the capillovirus group. These findings suggest that CTLV is a capillovirus.
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