Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 48 , Issue 4
Showing 1-22 articles out of 22 articles from the selected issue
  • Naoyuki MATSUMOTO, Toru SATO
    1982 Volume 48 Issue 4 Pages 419-424
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The competitive saprophytic abilities (CSA) of Typhula incarnata and T. ishikariensis, snow mold pathogens, were estimated by the Cambridge method. T. incarnata showed an excellent CSA, but that of T. ishikariensis was poor. T. ishikariensis biotypes B and C were most virulent followed by biotype A, and T. incarnata was least virulent. A compensating relationship between CSA and virulence was revealed in these two pathogens. This relationship was not clear in the biotypes of T. ishikariensis.
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  • Tsutomu UEMATSU, Armand TAKATSU, Kan-ichi OHATA
    1982 Volume 48 Issue 4 Pages 425-432
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A selective medium (PCSM) was developed for the isolation of Pseudomonas cichorii, one of the causal agents of bacterial rot of lettuce, from soil and plant debris. The composition of the medium was as follows: 0.5g KH2PO4, 3g Na2HPO4⋅12H2O, 8g sodium tartrate, 5g (NH4)2SO4, 25mg MgSO4⋅7H2O, 24mg Na2MoO4⋅2H2O, 10mg EDTA-Fe, 50μg L-cystine, 1mg methyl violet, 50mg pheneticillin potassium, 10mg ampicillin sodium, 10mg cetrimide, 25mg cycloheximide, 20mg phenol red, 100mg thirambenomyl wettable powder, 25mg potassium tellurite, 15g agar in one liter of distilled water. Colony forming efficiency of Ps. cichorii on PCSM was higher than that on King B medium. Reduction percentage of soil bacteria on PCSM changed with the kinds of soil, and it ranged from 92.9 to 99.9% of the total number of soil bacteria recovered on nutrient broth yeast extract agar.
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  • Kanichi MORI, Daijiro HOSOKAWA, Minoru WATANABE
    1982 Volume 48 Issue 4 Pages 433-443
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Multiplication and distribution of viruses in the stem tissues adjacent to the apical meristem of infected plants was studied by the fluorescent antibody technique and electron microscope observation. Combinations of viruses and plants used Were: tobacco mosaic virus-petunia, tobacco and tomato; cucumber mosaic virus-tobacco, petunia and cucumber: potato virus X-tobacco, potato, Nicotiana glutinosa and Datura stramonium; potato virus Y-tobacco and potato. In any combinations of virus and plant tested, no virus was detected in the apical meristem, in the region close to the base of meristem Where the tissue remained to be differentiated and in the very young leaf primordia on an early stage after generation from regions adjacent to the meristem. Virus was detected in the regions located below such parts, where tissue differentiation was considerably advanced. The virus content successively increased from less differentiated cells to move differentiated ones. In the leaf primordia, virus was first detected in the phloem when the vascular bundle became differentiated, and then spread to the lamina as the primordia grew.
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  • Daijiro HOSOKAWA, Kanichi MORI
    1982 Volume 48 Issue 4 Pages 444-451
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Multiplication and distribution of the virus in tobacco leaves mechanically inoculated with cucumber mosaic virus were examined by the fluorescent antibody technique. The epidermis which had been peeled off from the inoculated leaves was fixed and the inner side cell wall of epidermis was partially digested by cell wall degrading enzymes. The epidermis was then stained with a flourescent antibody. Primarily infected cells were observed in the epidermis 9 to 10hr after inoculation at 25C; the majority of the primarily infected cells were ordinary epidermal cells but some were subsidiary cells of stomatal guard cells. The virus antigen gradually spread concentrically from the primarily infected cells to surrounding cells. The rate of spreading of the antigen was 8.4μm, 20.3μm and 26.3μm per hour at 20C, 25C and 30C, respectively. In epidermal cells the antigen was first detected in the nucleolus-like bodies and thereafter it became distributed in cytoplasm and increased in its intensity of fluorescence. The virus appeared to move from an infected cell to an adjacent cell was observed to occur after a considerable amount of virus antigen had accumulated in the cytoplasm of the infected one. On the bases of the observation of leaf sections it is assumed that the virus first spread from the primarily infected site to both horizontal and vertical directions simultaneously, passing from cell to cell. After the virus reached the lower epidermis, it spread mainly in the horizontal direction.
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  • Takahiro MAKINO
    1982 Volume 48 Issue 4 Pages 452-457
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A new micropipette method was developed to determine the ice nucleation activity of bacterial cells. The micropipettes used for the experiments were the scaled capillary tubes (Drumond Scientific Co., USA). Deionized water could be overcooled lower than -20C. Ordinary physical shock did not significantly influence on the freezing temperatures with slight deviations. Temperatures of the samples in micropipettes could be controlled easily and accurately. Difference was rarely detected between the temperatures of ethanol in cooling bath and water samples in micropipettes dipped in the former. Ice nucleation temperature, however, varied with the capacities of the micropipettes, showing higher value with the larger capacities. Positive correlation was observed between ice nucleation temperatures and logarithms of capacity with 0.93 or higher values of correlation coefficient. This method was compared with the procedure described by Vali. Ice nucleation temperatures by the present method showed small deviation (1 to 3% in CV). The present method was considered to be superior to other methods including Vali's method and its modifications. The ice nucleation activity of plant pathogenic bacteria was measured by the method. Isolates of Pseudomonas syringae pv. pisi were very active and showed ice nucleation at -2.9C in contrast to P. marginalis pv. marginalis, P. s. pv. maculicola and P. s. pv. tabaci. The other species of Pseudomonas showed no activity. No activity was also observed with follows: Corynebacterium michiganense pv. michiganense, C. flaccumfaciens pv. oortii, Erwinia carotovora subsp. carotovora, E. herbicola, E. milletiae, and X. campestris pv. campestris. Cultures of epiphytic bacteria isolated from Actinidia cinensis, Cyclobalanopsis spp., Eriobotrya japonica, Ficus carica and prunus avium showed ice nucleation activity at -2.7 to -3.0C. Deionized water in which plant buds were dipped for 3 days increased significantly ice nucleation activity due to bacteria. This method may be effective in detecting the active gemmisphere bacteria as ice nuclei.
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  • Makoto KOJIMA, Tsutomu TAKIZAWA, Ichiro UYEDA, Eishiro SHIKATA
    1982 Volume 48 Issue 4 Pages 458-465
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Potato leafroll virus (PLRV) antigen was easily detected by enzyme-linked immunosorbent assay (ELISA) in potato foliage which had been collected in commercial fields or grown in a greenhouse. ELISA values were highest in newly expanded leaves and gradually declined with growth. When infected tubers were planted, viral antigen generally could be detected by ELISA before the development of symptoms on potato foliage. The pattern of results of ELISA tests using field-grown potato plants closely corresponded to the pattern of symptom development on potato plants. Since we were able to eliminate the non-specific background of the extracts from healthy green sprouts and tubers by heating for 10min at 50C, ELISA can be employed for PLRV-indexing using green sprouts or tubers. The ELISA values for leaf material desiccated over silica gel remained relatively constant throughout one month of storage and PLRV antigen was readily detected in dried samples. In comparative studies by ELISA and immunosorbent electron microscopy (ISEM), no obvious differences in ability to detect the PLRV antigen were observed. PLRV antigen (in purified preparations) could be accurately detected at even nanogram levels by both immunolological methods.
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  • Tsuneo NAMAI, Susumu YAMANAKA
    1982 Volume 48 Issue 4 Pages 466-470
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    This investigation was carried out to determine the appearance of variants in virulence by pairing-inoculation of 2 different pathogenic isolates (races 047 and 303) of rice blast fungus, Pyricularia oryzae Cavara, on both agar media and rice leaves. The mycelium-joining method on media, and the methods of the punch-inoculation of mixed spore suspension and the pairing-inoculation on leaves using the above 2 parent isolates, induced to arise some variants having virulence different from that of the parent isolates. These variants were divided into 2 groups; one contained the isolates (races 337, 317, 313, 137 and 037) that newly acquired the strong pathogenicity for 2 rice varieties, Kanto 51 and Tsuyuake, to which the parent isolates were non-pathogenic, and the other contained the isolates (race 347) that had both pathogenicity of the parent isolates. On the other hand, no variants in virulence appeared from the parent isolates. The race 337 isolate arised in both experiments on agar media and rice leaves. In addition, the variants were divided into 3 groups by the colony type and the color of culture on potato decoction agar medium. Thus, it was suggested that the variants in this experiment might be resulted from the anastomosis of the parent isolates.
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  • Katsumi AKUTSU, Yumiko KOBAYASHI, Tadakazu WATANABE, Keido KO, Tomomas ...
    1982 Volume 48 Issue 4 Pages 471-481
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Purine-related compounds, cyclic AMP, 5'-AMP, 5'-IMP, adenosine and inosine, induced formation of secondary appressoria of Botrytis cinerea on slide glass in the presence of glucose. Among these purine-related compounds, formation of the secondary appressoria was remarkable in inosine. Formycin B, which is an analogue to inosine, reduced inductive effects of the secondary appressoria with inosine, and competed with inosine in forming the secondary appressoria. The administration of inosine to mycelia of B. cinerea resulted in an increase of syntheses of both DNA and RNA, followed by an increase of protein synthesis. When the mycelia incorporated 14C-inosine were fractionated, radioactivity was detected in RNA fraction at early time after incubation, and afterward in DNA fraction. Formycin B did not inhibit biosynthesis of cellular macromolecules in the mycelia, but inhibited DNA synthesis stimulated with inosine. It was shown that formycin B competed with inosine for DNA synthesis. These results indicated that inosine stimulated DNA synthesis, followed by an increase in RNA and protein syntheses in the mycelia, resulting in induction of the secondary appressoria.
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  • Shigemitsu TORIYAMA
    1982 Volume 48 Issue 4 Pages 482-489
    Published: September 25, 1982
    Released: February 19, 2009
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    Purified rice stripe virus preparation contains three RNA species whose molecular weights were determined as 1.4×106, 1.0×106 and 0.9×106 in the polyacrylamide gel electrophoretic analysis under the 7M urea-denatured conditions. These RNAs were linear molecules with length distribution from 1.2μm to 0.2μm, as observed by electron microscope. RSV was separated into top, middle, sometimes appearing as a peak with a shoulder, and bottom components by sucrose density gradient centrifugation. The top component may be an artifact resulting from degradation during purification. RNA of mol. wt 1.4×106 was associated with the bottom component and RNAs of mol. wt 1.0×106 and 0.9×106 were associated with the middle component apparently consisting of two components, which were not easily separable by sucrose density gradient centrifugation. On the other hand, the RNA of top component seemed to be degraded into various sizes.
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  • Osamu TAMURA, Izumi SAITO
    1982 Volume 48 Issue 4 Pages 490-498
    Published: September 25, 1982
    Released: February 19, 2009
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    Single hyphae of the Valsa ceratosperma, the causal fungus of apple canker, can invade the cortical tissues and phloem of apple bark very slowly during the dormant season. A transition zone composed of collapsed cells was found between diseased and healthy tissues. Invasion by single hyphae also occurred in the early growing season (May) when the development of canker lesion was most active. As temperature rised from June to July, several cell layers were lignified in the transition zone beyond the mycelial invasion, followed by the formation of cork layers with thin-walled cork cells. In this season, the fungus proliferated to form a fan-shaped mycelium and destroyed the wound cork layers by their mass action. However, repeated formation of wound cork layers resulted in a decreased rate of lesion development. Wound cork layers with thick-walled cork cells which were formed in August may play a role as a complete barrier against invasion by the causal fungus. With a decline of temperature in autumn, mycelium was again able to invade healthy tissue by penetrating through defective cork layers between the periderm and cortex or phloem and xylem. When apple bark was artificially wounded, wound cork layers were produced slowly during winter, but rapidly during summer. From the results presented here it was concluded that wound cork layers formed as a result of mycelial infection act as a temporal barrier to invasion and their rate of formation depends on the host metabolic activity.
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  • Teruyoshi HASHIBA, Kenji KOIKE, Ichiro YUNO, Masao YAMADA
    1982 Volume 48 Issue 4 Pages 499-505
    Published: September 25, 1982
    Released: February 19, 2009
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    Vertical disease development of sheath blight caused by Rhizoctonia solani Kühn was investigated with a rice cultivar, Koshijiwase, under different temperature and relative humidity. Model curves of the vertical development of lesions were made according to different temperature, relative humidity and susceptibility of the rice plants. Vertical development of lesions on rice plants under 100% relative humidity (RH) was 0.48cm at 20C; 1.13cm at 23C; 1.35cm at 25C and 1.58cm at 28C. The first model curve was obtained by a calculation of the vertical development of lesions under the average temperature. The ratios of vertical development of lesions under different relative humidity to that under 100% relative humidity (at 25C) were 0.99 at 98% RH; 0.96 at 95% RH; 0.87 at 90% RH and 0.38 at 86% RH. The second model curve was obtained as modified the first one according to the relative humidity. The susceptibility of leaf sheaths to a sheath blight fungus correlated with their maturity. The vertical development of lesions observed on 2-, 5-, 10-, and 15-day-old sheaths after heading under the most favorable conditions (at 28C, 100% RH) was 1.12, 1.32, 1.71, and 1.59cm per day, respectively. When the daily calculation values of vertical development of lesions were larger than the values calculated from the susceptibility of leaf sheaths, the values calculated from the susceptibility for each day were used. Thus, the final model curve of the vertical development of lesions calculated from the temperature, relative humidity and susceptibility of leaf sheath almost co-incide with the vertical development of lesions in paddy fields in 1971 to 1981. These models will be useful for forcasting of rice sheath blight.
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  • Hironori KOGA, Takashi KOBAYASHI
    1982 Volume 48 Issue 4 Pages 506-513
    Published: September 25, 1982
    Released: February 19, 2009
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    Early infection process of Pyricularia oryzae Cav. in the rice leaves of the compatible combination of race 037 and var. Koshihikari, and the incompatible combination of race 037 and var. Fukunishiki was compared under microscope with an aid of the whole-leaf clearing and staining technique. The difference became apparent at the stages of fungal penetration and mycelial growth. The host reactions in the epidermal cells at the early stage of penetration were grouped into two types, i.e. no-reaction and granulation of host cellular contents. The rate of no-reaction at the penetration sites in the incompatible combination was almost at same as that in the compatible one. Therefore, it seemed that unsuccessful penetration without any host reaction was independent of the specific resistance controlled by the major gene (Pi-z) for resistance to rice blast. On the other hand, the rate of unsuccessful penetration sites with the host cytoplasmic granulation in the incompatible combination was distinctly higher than that in the compatible one, and the time when the granulation of the host cellular contents appeared was coincident with the time when the difference of the penetration percentage between two combinations became apparent. Hence it was suggested that the granulation of the host cellular contents closely correlated with the expression of the specific resistance. Moreover, cessation of mycelial growth in the incompatible combination also closely correlated with occurrence of the granulation of the host cellular contents. It was unlikely that occurrence of the deep-browning of infected host cells was the primary determinants of the specific resistance, because the rate of the infection sites with the deep-browning was very few in the incompatible combination, and the occurrence of the deep-browning was also observed in the compatible combination as in the incompatible one.
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  • Shigemitsu TORIYAMA
    1982 Volume 48 Issue 4 Pages 514-520
    Published: September 25, 1982
    Released: February 19, 2009
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    Cocksfoot mosaic disease is prevalent in old cocksfoot pastures in northern and central districts of Japan. By mechanical inoculation, the virus disease transmitted readily to cocksfoot and wheat. Barley, oat and rye were also infected, but with difficulty. Setaria italica, S. viridis, bromegrass, fescue, rye-grass, thimothy and maize were not susceptible to the virus. The virus particle was spherical and about 28nm in diameter. The virus contained an RNA species having a mol. wt. of approximately 1.4×106 and a coat protein of 29, 000 in mol. wt. Thermal inactivation point was 80-85C. Two isolates of the virus, CL and M reacted strongly with the antiserum of cocksfoot mottle virus (by courtesy of Dr. Hollings, England), but not with either the antiserum of cocksfoot mild mosaic virus (by courtesy of Dr. Huth, West Germany) or the antiserum of phleum mottle virus (by Dr. Hollings, England). On the other hand, the antisera of isolates CL and M (titers, ×320) reacted positively with cocksfoot mottle virus, but with neither cocksfoot mild mosaic virus nor phleum mottle virus. Thus the virus of cocksfoot mosaic disease was identified as cocksfoot mottle virus.
    No serological difference could be found among isolates CL, M and SN, which were isolated from cocksfoot plants manifesting different symptoms: chlorotic streak, mild mosaic and mild mosaic with severe necrosis, respectively. In particular, four major cultivars of cocksfoot in Japan were susceptible to the cocksfoot mottle virus. Cultivars, Aonami, Akimidori and Kitamidori were especially susceptible and Okamidori was rather resistant.
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  • Hiroki KOGANEZAWA, Tsutomu SAKUMA
    1982 Volume 48 Issue 4 Pages 521-528
    Published: September 25, 1982
    Released: February 19, 2009
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    Solution of diethyl ether extracts from culture filtrate of Valsa ceratosperma, a causal agent of apple Valsa canker, grown in a medium containing apple bark components caused similar bark necrosis to the canker on naturally infected apple trees. Three toxic substances were purified from culture extracts by column chromatography and were identified by co-chromatography and by ultraviolet absorption spectra. The toxic substances included phloretic acid (p-hydroxypropionic acid), p-hydroxybenzoic acid and protocatechuic acid which are known to be breakdown products of phloridzin. In cut stem bioassay these compounds showed a toxicity only in high concentrations. The toxicities of the compounds were not host specific.
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  • Ko SAWAI, Toshikatsu OKUNO, Takako ITO
    1982 Volume 48 Issue 4 Pages 529-531
    Published: September 25, 1982
    Released: February 19, 2009
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  • Minoru TAMURA
    1982 Volume 48 Issue 4 Pages 532-533
    Published: September 25, 1982
    Released: February 19, 2009
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    In 1981, bacterial leaf and flower spot of zinnia was found in Ishikawa pref., Japan. The disease first appeared on the leaves as yellowish small circular spots. Those spots slowly enlarged to angular shape about 5mm in diameter and became reddish or dark brown. Lesions of flower were dark or blackish brown spots. The bacteriological tests and host range indicated that the pathogen was Xanthomonas campestris pv. zinniae (Hopkins & Dowson 1949) Dye 1978.
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  • Daijiro HOSOKAWA, Kanichi MORI
    1982 Volume 48 Issue 4 Pages 534-537
    Published: September 25, 1982
    Released: February 19, 2009
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  • Mamoru SATO
    1982 Volume 48 Issue 4 Pages 538-541
    Published: September 25, 1982
    Released: February 19, 2009
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    A protozoa feeding on Pseudomonas syringae pv. mori was isolated from a subculture of the bacterial strain. The organisms formed plaques on culture of P. s. mori and the other bacteria including Xanthomonas campestris pv. citri and Erwinia carotovora subsp. carotovora. Some cultural conditions for plaque formation and the other properties of the organisms were also reported.
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  • Kiroku KOBAYASHI, Tadao UI, Izumi SAITO
    1982 Volume 48 Issue 4 Pages 542-543
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Sakae ARASE, Mitsunobu TANISHIKI, Setsumi ITOI
    1982 Volume 48 Issue 4 Pages 544-546
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Shigeo MURAKOSHI, Shunichiro HOSOYA
    1982 Volume 48 Issue 4 Pages 547-550
    Published: September 25, 1982
    Released: February 19, 2009
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    Isolates of Botrytis cinerea Persoon resistant to iprodione were obtained from three tomato fields in Kanagawa prefecture, Japan. The minimal inhibitory concentration value of iprodione for the isolates was about 25ppm. The isolates were cross-resistant to procymidone and vinclozolin. Resistance to benomyl was also found in all the iprodione resistant isolates in this experiment. The virulence of the isolates on broad bean leaves were correspond to that of sensitive isolates. One of the isolate had an ability to develop the disease even on the tomato leaves that treated with 500ppm solution of iprodione, procymidone, vinclozolin, benomyl or thiophanate-methyl.
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  • Kazuo MIYAHARA, Masafumi MATSUZAKI, Kinji TANAKA, Nobumichi SAKO
    1982 Volume 48 Issue 4 Pages 551-554
    Published: September 25, 1982
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A new disease of onion (Allium cepa) caused by mycoplasma-like organism (MLO) was found in Saga Prefecture. The typical symptoms of diseased onion leaves were yellowing and stunting with fasciculation. Hypertrophy of the diseased onion bulb was decreased while flower clusters of the bulb were teratoid. The diseased onion bulb during storage was sprouted earlier than healthy one. In ultrathin sections of the diseased onion, MLO was observed in the sieve tubes of diseased leaves. In transmission tests with 5 species of wild planthopper and leafhoppers, only Macrosteles orientalis could inoculate and transmit the MLO to onion seedlings. The inoculated seedlings expressed the typical symptoms 20-28 days after transmission tests and MLO was detected in the sieve tubes of the onion leaves. The transmission rate of MLO by naturally infested M. orientalis ranged from 3.3 to 33%. The results indicate that the causal agent of this disease seemed to be MLO, and this disease was proposed to name “Onion yellows”.
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