Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 51 , Issue 4
Showing 1-18 articles out of 18 articles from the selected issue
  • Kenji TAKAHASHI, Tadaoki INABA, Tadashi MORINAKA
    1985 Volume 51 Issue 4 Pages 399-404
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Preinoculation of the primary leaves of bean plants (Phaseolus vulgaris) with Colletotrichum lindemuthianum (bean anthracnose) at concentrations above 5.0×104 conidia per ml inhibited the development of boan rust (Uromyces appendiculatus) on the first trifoliolate leaves.
    The induced resistance was systemic being expressed by decrease in the number of uredia, retardation of formation and maturation of uredia, and reduction of the size of uredia and chlorotic halos surrounding the uredia. The preinoculation of one of the primary leaves with C. lindemuthianum also inhibited the development of bean rust on the opposite primary leaf. Although the size of uredia and chlorotic halos surrounding the uredia were reduced, the number of uredia was not decreased, and the formation and maturation of uredia were not retarded.
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  • Toshimichi YOSHIZAKI, Teruo SANO, Ichiro UYEDA, Eishiro SHIKATA
    1985 Volume 51 Issue 4 Pages 405-412
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The effects of the addition of bentonite, tannic acid, sodium oxalate, yeast-RNA, RNase, acridine orange, methylene blue, and toluidine blue on the infectivity of cucumber isolate of hop stunt viroid (HSV-C) were assayed by means of the infectivity index. The infectivity of HSV-C was increased by bentonite, but was not by sodium oxalate and yeast-RNA. The infectivity of HSV-C was increased slightly by tannic acid at a concentration of 0.1mg/ml, and decreased by tannic acid or yeast-RNA at a concentration of 1.0mg/ml. HSV-C was completely inactivated by pancreatic RNase, and the inactivation was appreciably counteracted by the addition of bentonite to the mixture of HSV-C and RNase. HSV-C was inactivated by the addition of acridine orange, methylene blue, or toluidine blue O to HSV-C under the irradiation of visible light, while the infectivity of HSV-C was slightly reduced when incubated in a dark room. The inactivating effect of methylene blue was higher than that of the other dyes. The inactivation of HSV-C by dyes was obviously counteracted with the addition of bentonite to the mixture of HSV-C and dye.
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  • Fumiyoshi FUKUMOTO, Hiroshi TOCHIHARA
    1985 Volume 51 Issue 4 Pages 413-420
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Freezing for a duration of one hour followed by thawing prevented changes in the infectivity of a purified preparation of southern bean mosaic virus (SBMV) suspended in 10mM potassium phosphate buffer (P.B.), pH 7.0. Infectivity of purified SBMV decreased gradually during the storage under frozen conditions at -20C. However, the infectivity was maintained at a high level for 52 months by the addition of peptone or glycerol, etc. At -70C, the infectivity was maintained for a long period without any additives. The virions of purified SBMV freeze-dried without additives became swollen by rehydration with P.B., and their infectivity decreased to 16%. But, the changes in the conformation of SBMV virions due to freeze-drying could be significantly prevented by the addition of lysine. The protective effect of additives during preservation of freeze-dried preparations was assessed at 65C. The infectivity of freeze-dried preparations in P.B. disappeared in one day but it could be detected 7 days after preservation, when the virus was freeze-dried with lysine.
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  • Katsuhiko ANDO, Keizo KATSUYA
    1985 Volume 51 Issue 4 Pages 421-425
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The reproductive colonies were obtained from the uredinial stage of Puccinia recondita f. sp. tritici race 45. Urediniospores produced in the colonies were inoculated to seedlings of the wheat cv. Norin No.16. The strains obtained from the reinfections were examined in backcross lines of wheat with single genes for resistance to leaf rust and differential varieties for wheat leaf rust race identification. The reactions of the strains to the wheat lines and the differentials were different from those of the original race 45. During the axenic culture of the wheat leaf rust fungus, various races appeared.
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  • Mamoru SATO, Koushi NISHYAMA, Nickolas J. PANOPOULOS
    1985 Volume 51 Issue 4 Pages 426-434
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The conjugational proficiency and replicative ability of plasmid pBPW1, found in Pseudomonas syringae pv. tabaci BR2, in P. syringae pathovars mori, atropurpurea, tabaci, eriobotryae and glycinea were examined. The plasmid was transferred and maintained as an autonomous replicon in ca. 40% of the strains at frequencies ranging from ca. 10-6 to 100% per recipient. These strains also expressed donor ability for pBPW1, with transfer frequencies ranging from 10-6 to 100%. In other strains the plasmid was apparently transferred but unable to replicate. This behaviour suggests that pBPW1 is potentially useful as a suicidal carrier for transposon mutagenesis in these strains. With one exception, the bacteriological properties of transconjugants were identical to those of the wild type recipient strains. The exception was pv. atropurpurea NIAES 1309 transconjugants, the majority of which aggregated in King's B broth and had altered serological properties. These findings suggest that pBPW1 carries a gene(s) responsible for cell aggregation and antigen alteration. However, the gene expression depends on the host's genetic background and does not occur in all hosts.
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  • Yuichi YAMAOKA, Keizo KATSUYA
    1985 Volume 51 Issue 4 Pages 435-442
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Urediniospores produced in the axenic cultures of five isolates, Mca-1A, Mco-1A, Mep-1A, Met-1A and Mhu-2B which were derived from the uredinial stage of five Melampsora species parasitic on willows, were examined for their germinability and infective ability. The urediniospores produced in the isolates grown on QMS-7 medium, except for isolate Mca-1A, neither germinated nor infected the respective host plants. In contrast, urediniospores produced on HOR medium (isolates Mco-1A, Mep-1A and Met-1A) and on OR medium (isolate Mhu-2B) germinated and infected the respective host plants. By using isolate Mhu-2B, effects of vitamins and agar added to media on which the colonies grew on the germinability and the infective ability of urediniospores produced in the colonies were defined. Kinds of agar added to the media affected the germinability and infective ability of urediniospores, while vitamins had no effect. It is suggested that water-soluble substance(s) contained in Difco Bacto-agar promote or enhance the germinability of urediniospores produced in the colonies.
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  • Tadaoki INABA, Tadashi MORINAKA
    1985 Volume 51 Issue 4 Pages 443-449
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Four isolates of the spinach downy mildew pathogen, Peronospora effusa were used. Two isolates, K1 and K2, belonged to the mating type P1, and two isolates, M1 and A1, to the mating type P2. Seedlings of spinach at the cotyledon stage were inoculated with conidia of each isolate or a mixture of conidia in paired combinations of two mating types (isolates K1 and M1, or isolates K2 and A1) in which each conidial suspension was mixed in equal volume before inoculation. The leaves infected with conidia of either one of the mating types, P1 or P2, produced only conidia from the 3rd day after inoculation. The leaves infected with a mixture of conidia of the two mating types, P1 and P2, produced oogonia and oospores from the 4th and 5th day after inoculation, respectively, and in those leaves conidium production was delayed and suppressed. Cotyledons were inoculated with a mixture of conidia in paired combinations (isolates K1 and M1, or isolates K2 and A1) in the mixing ratios of 100:1, 1:1, 1:100(v/v), and the incidence of oospore production as well as intensity of conidium production in the infected leaves was observed. In the infected leaves which produced oospores at a high level, conidium production was reduced; whereas in the infected leaves which produced oospores at a low level, abundant conidia were formed. Moreover, the site of conidium production was completely different from that of oospore production. From these results, it was demonstrated that the leaves infected with a mixture of conidia of two mating types formed oospores in the early days after infection without producing conidia, and in those leaves conidium production was suppressed because the site where oospores were produced was different from that where conidia were formed.
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  • Mabito IWASAKI, Masaaki NAKANO, Akira SHINKAI
    1985 Volume 51 Issue 4 Pages 450-458
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Filamentous particles associated with rice grassy stunt were purified from the infected rice plants. The filamentous particles were 6-12nm in width. An antiserum to the filamentous particles specifically reacted to extracts of grassy stunt-infected leaves and -viruliferous planthoppers, Nilaparvata lugens by agar gel double diffusion test. The antibody neutralized the infectivity in extracts of grassy stunt-infected rice leaves. In enzyme-linked immunosorbent assay (ELISA), the filaments were detected in extracts of grassy stunt-exposed planthopper population up to a dilution of one planthopper/8ml and also from extracts of the infected leaves at 1/100, 000 dilution. Extracts of virus-free insects and healthy rice leaves did not give a positive reaction in ELISA. The purified filamentous nucleoprotein reacted positively even when diluted to A260=1.0×10-5. The infective planthoppers stored at 25C for 1 month and the infected rice leaves stored at room temperature for 4 months gave positve reactions, but the intensity of the reactions was lower than that in fresh or frozen materials. In the exposed planthopper populations, 40% of the insects transmitted the causal agent and gave a positive reaction in ELISA, 41% failed to transmit the agent but gave a positive reaction, while both tests were negative in the remainder. The brown planthoppers that migrated across the South China Sea were collected and tested for the presence of the filaments in ELISA in 1982. About 0.1% of the total 1, 126 individuals tested gave positive reaction.
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  • Yukio SHIRAKO, Yoshio EHARA
    1985 Volume 51 Issue 4 Pages 459-464
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Both type A and type B viruses isolated from downy mildew-diseased rice plants contained single-stranded RNA (ssRNA) as determined by susceptibility to formaldehyde and RNase A, resistance to DNase I and fluorescence with two dyes, Hoechst 33258 and acridine orange. Type A virus had two species of polypeptides with molecular weights (MWs) 43×103 and 39×103 and three segments of ssRNA with WMs 1.1×106, 0.7×106, and 0.33×106. The relative amounts of the largest two RNAs were similar in all isolates but that of the smallest RNA varied among the isolates. Type B virus had one species of polypeptide with MW 41×103 and one ssRNA with MW 1.8×106.
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  • Hisashi IWAI, Satoshi WAKIMOTO
    1985 Volume 51 Issue 4 Pages 465-474
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The particles of soybean mosaic virus (SMV) was successfully purified without inactivation by the following improved method. The soybean leaves infected with SMV were homogenized with two volumes of 0.3M Na-phosphate buffer (pH 7.0) containing 0.01M Na-DIECA and chloroform-butanol (each 8% v/v). The crude sap was filtered through two layers of cheesecloth and centrifuged at low speed (8, 500×g, 10min). The supernatant was supplied with 6% PEG and 0.1M NaCl. After 30min of incubation at 4C, the suspension was centrifuged at low speed, the precipitate obtained was resuspended in 0.05M Na-phosphate buffer (pH 7.0) containing 0.005M Na-EDTA, and ultrasonicated for 10 to 30 seconds. The virus fraction was collected by two cycles of differential centrifugation combined with ultrasonication just before each low speed centrifugation. The virus fraction was then subjected to the sucrose density gradient centrifugation for final step of purification. The purified virus thus obtained was highly infective. It showed the maximum ultraviolet absorption at 260nm and minimum at 247nm with a slight shoulder at 290nm. The ratio of A280/A260 was 0.76, indicating the nucleotide content of about 5.5%. The yield was 4.0 to 13.5mg per 1kg of the infected leaves.
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  • Hisashi IWAI, Tsutae ITO, Koji SATO, Satoshi WAKIMOTO
    1985 Volume 51 Issue 4 Pages 475-481
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The distribution patterns of soybean mosaic virus (SMV) strains B (mild strain) and D (severe strain) in the seeds of soybean cultivar Hyuga were compared at different growth stages by applying enzyme linked immunosorbent assay (ELISA) and bioassay on French bean cultivar Top Crop. ELISA was more sensitive than bioassay. At immature seed stages such as full seed stage and yellowish pod stage, both strains were detected in seed coat and embryo, but only SMV-B was detected in cotyledon. As seeds becoming mature, detection values obtained by both methods were generally declined, especially in the seed coat at full maturity stage, both strains lost their infectivity. The detection values of SMV-B were remarkably higher than those of SMV-D, showing high correlation between the value and ability of seed transmission. The infectious virus in embryo is considered to be responsible for transmission of the virus but the virus in seed coat also had some effects on seed transmission of the virus. The degree of seed mottling was higher by the infection with SMV-D than with SMV-B and it did not correlate with transmissibility of the virus.
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  • Rokuo ZENBAYASHI, Saburo SHIBUKAWA, Tsuneo WATANABE
    1985 Volume 51 Issue 4 Pages 482-485
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A new disease of arrowhead plants with brown lesions in petioles occurred in Saitama prefecture. Because of the easiness of breaking-off of the diseased petioles, the growth of the plants was remarkably retarded. Pythium myriotylum was isolated very frequently from the diseased tissues and it showed pathogenicity to the petioles of arrowhead planted in artificially infested soil with the fungus, 83-193.
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  • Keiichi TOMARU, Yukio SAWA, Susumu KUBO, Shigeru KUWATA, Ikuo SUZUKI
    1985 Volume 51 Issue 4 Pages 486-489
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Tobacco streak virus (TSV) was isolated from Burley tobacco plants showing yellowing and veinal necrosis of leaves. Plants of 21 species from 10 genera were infected by the virus. The virus had properties of thermal inactivation point 50-55C, dilution end point 10-3-10-4 and longevity in vitro 12-24hr, and positively reacted with TSV antisera. Virus particles were isometric with 27-35nm in diameter. An isolate from symptomless dahlia plant was also identified as TSV. This is the first report of natural occurrence and isolation of TSV in Japan.
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  • Sakae ARASE, Toshiaki OKA
    1985 Volume 51 Issue 4 Pages 490-493
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Norio SATO, Yuko YOSHIZAWA, Hiroshi MIYAZAKI, Akio MURAI
    1985 Volume 51 Issue 4 Pages 494-497
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Nobuaki MATSUYAMA, Satoshi WAKIMOTO
    1985 Volume 51 Issue 4 Pages 498-500
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Noboru SHIRANE, Yoshihachi WATANABE
    1985 Volume 51 Issue 4 Pages 501-505
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Hiroshi KAMIUNTEN, Junichiro YAMAGUCHI, Satoshi WAKIMOTO
    1985 Volume 51 Issue 4 Pages 506-508
    Published: October 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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