Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 57 , Issue 5
Showing 1-21 articles out of 21 articles from the selected issue
  • Kazusato OHSHIMA, Tatsuji HATAYA, Teruo SANO, Alice Kazuko INOUE, Eish ...
    1991 Volume 57 Issue 5 Pages 615-622
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Biological properties of potato virus Y-ordinary strain (PVY-O isolate) and necrotic strain (PVY-T isolate) isolated from potatoes in Japan were compared. PVY-O did not produce necrotic symptoms on Nicotiana tabacum, but produced necrotic local lesions on Chenopodium amaranticolor and C. quinoa. On the other hand, PVY-T produced necrotic flecks and veinal necrosis symptoms on N. tabacum, but did not infect C. amaranticolor and C. quinoa. The use of monoclonal antibodies specific to PVY-O and PVY-T indicated that both strains were not mixed-infected in inoculated plants respectively each other. The nucleotide sequences of the coat protein gene of these two strains were determined. Numbers of nucleotides encoding coat protein of both PVY-O and PVY-T were 801, and numbers of predicted amino acids were 267. Percentage amino acid sequence homology between PVY-O and PVY-T was 91.4%. In comparing the amino acid sequence between PVY-T and other PVY belonging to necrotic strains previously reported in Japan and foreign countries, homology of PVY-TH isolated in Japan and that to PVYN (N) isolated in the Netherlands was 98.5%, but homology to PVYn (F) isolated in France was 93.3%. Amino acid sequence of the N-terminal regions of coat protein varied in sequence in PVY isolates (strains) whereas the C-terminal were highly homologous. Furthermore, amino acid sequences which could discriminate an ordinary strain from a necrotic strain were not found.
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  • Seisaku UMEMOTO
    1991 Volume 57 Issue 5 Pages 623-628
    Published: December 25, 1991
    Released: February 19, 2009
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    The correlation between the development of Japanese pear scab (caused by Venturia nashicola) on leaves and the content of total nitrogen, total carbon, phosphorus, potassium, calcium, magnesium, iron and manganese in the leaves on trees given different amounts of nitrogen fertilizer was investigated. With an increase of nitrogen fertilizer, the content of total nitrogen and manganese in leaves increased while calcium content decreased. The content of total carbon, phosphorus, potassium, magnesium and iron did not show any obvious change. The ratio of diseased leaves, degree of disease development and degree of conidial formation increased with increasing amounts of given nitrogen fertilizer. Significant correlation (P=0.05) were recognized between total nitrogen content and the degree of disease development on 3rd and 7th position leaves from top leaf, the degree of conidial formation on 11th position leaf, calcium content and degree of disease development on 7th position leaf, and manganese content and degree of conidial formation on 7th position leaf. These results show that with an increase in nitrogen fertilizer there is an increase in total nitrogen and manganese content and a decrease in calcium content in leaves, and a higher susceptibility to Japanese pear scab was induced.
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  • Akira MORITA
    1991 Volume 57 Issue 5 Pages 629-633
    Published: December 25, 1991
    Released: February 19, 2009
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    The effects of the inoculation of Pseudomonas syringae pv. eriobotryae on the terminal buds, grafted parts and leaves of one-year-old loquat plants upon plant growth, lesion formation and fruit productivity were surveyed for eight years after inoculation. It has been observed that the growth of plants inoculated to their terminal buds was reduced within the four or five years after inoculation in comparison to that of the uninoculated plants, especially in respect of plant height, trunk diameter and crown area. Similar phenomena have also been observed in the case of grafted parts of inoculated plants within two years after inoculation. There was no differences in the total number of leaves between the terminal bud of inoculated and uninoculated healthy plants, but in comparison to the healthy ones terminal bud of inoculated plants has more younger leaves instead of older ones. In the case of grafted part of inoculated plants, the total numbers of both the younger and older leaves were fewer and the sizes of the leaves were also smaller than those of the uninoculated ones. Increased number of branching with shorter in length had been recorded in the terminal buds of inoculated plants compared to that of the healthy plants, whereas no marked differences on the number and size of the twigs had been observed among the leaves inoculated and uninoculated healthy plants. In respect of the development of lesions, the highest number of 259.3 lesions per plant has been developed within eight years in the terminal buds of inoculated plants and a considerable lesions developed on the grafted parts of inoculated plants. In response to the fruits production on both the terminal bud and grafted part inoculated plants were exceedingly decreased compared to that of the uninoculated healthy plants due to the infection of the seedling stages which ultimately reduced, stunted and distorted the growth of the plants. In the inoculated plants, the number of flower buds and of fruit clusters reduced to resulting dramatic yield losses.
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  • Hitoshi NAKAYASHIKI, Kappei KOBAYASHI, Seiji TSUGE, Tetsuro OKUNO, Iwa ...
    1991 Volume 57 Issue 5 Pages 634-640
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Aphid transmissible Japanese isolate of caulifiower mosaic virus M (CaMV-M) was cloned into pUC19 and its ORF II region was sequenced. Comparison of this sequence with that of CM1841 (non-aphid transmissible isolate of CaMV) showed that there were nine base changes, four of which gave rise to alterations in the predicted amino acid sequence. Characterization of in vitro recombined hybrid viruses between CaMV-M and CM1841 showed that 5' half of ORF II was responsible for the lack of aphid transmissibility in CM1841 and this region influenced the amount of accumulation of ORF II product in the infected leaves.
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  • Siti Muslimah WIDYASTUTI, Fukuji NONAKA, Keisuku WATANABE, Eiko MARUYA ...
    1991 Volume 57 Issue 5 Pages 641-648
    Published: December 25, 1991
    Released: February 19, 2009
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    Accumulation and antifungal activity of a second newly isolated phytoalexin of Rhaphiolepis umbellata Makino, rhaphiolepsin, were described. The phytoalexin was accumulated in the leaves infected with Entomosporium mespili or Pestalotiopsis sp. The accumulation of 4'-methoxyaucuparin, the first phytoalexin of R. umbellata, was started one day after inoculation and it remained stably for about 6 days and then declined during the next 6 days. On the other hand, rhaphiolepsin started to accumulate in the leaves at the 8th and reached the maximum accumulation of 2.147μg/g fresh leaves at 28th days after inoculation. The inhibitory action of rhaphiolepsin against the fungi was stronger than that of 4'-methoxyaucuparin.
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  • Zenichi MOROMIZATO, Fumie ISHIZAKI, Konomi TAKARA, Masao TAMORI
    1991 Volume 57 Issue 5 Pages 649-656
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    None or very few sclerotia of Rhizoctonia solani (AG-1, IA) were formed on Hopkins agar medium without KH2PO4, though hyphae developed in some extent. While, the number and weight of sclerotia were decreased when MgSO4 was absent. As KH2PO4 in the basal medium was replaced with other phosphates different in cation, sclerotia were well formed. The optimal concentration of phosphate as KH2PO4 for the sclerotium formation, in number and weight, and hyphal development was in the region of 100ppm. The addition of magnesium resulted in the increase of the number and weight of sclerotia proportionally with the amount of the magnesium compound. The results indicate that phosphorus ion is indispensable to the sclerotium formation, whereas magnesium ion is promotive. The absence of phosphorus at the maturing stage resulted in the formation of few sclerotia, even though phosphorus was presented at the hyphal and initial phases. While defficiency of phosphorus in the early stage of sclerotium development showed no effect on the number and weight of sclerotia formed, if the phosphorus was supplied in subsequent periods. The branching internodes of hyphae grown on the phos-phorus free medium were longer than those of on the medium containing phosphorus. This decrease of the hyphal branching will lead to the decrease of interweaving hyphae and will result in the scarce sclerotium formation. A large accumulation of 32P to sclerotia was strikingly observed in this experiment.
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  • Nobuhiko NAKASHIMA, Zenichi MOROMIZATO, Nobuaki MATSUYAMA
    1991 Volume 57 Issue 5 Pages 657-662
    Published: December 25, 1991
    Released: February 19, 2009
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    Chaetomium trilaterale var. diporum RC-5 was isolated from sclerotia of Sclerotinia sclerotiorum buried in soil in Okinawa Prefecture. Since the isolate inhibited mycelial growth of S. sclerotiorum on PDA medium, the purification of the antifungal substance was undertaken. The antifungal substance was produced in modified Richards medium. The substance was isolated by extraction with chloroform and thin layer chromatography. Its molecular formula was determined as C31H35O8N (mol wt 549) on the basis of elementary analysis and fast atom bombardment mass spectrometry (FAB-MS). Mycelial growth of S. sclerotiorum and Botrytis cinerea was inhibited intensively and their hyphal tips were branched abnormally by the treatment with antifungal substance. Their ED50 values on PDA medium were ca. 10ng/ml, and they were more than 20 times stronger than that of cycloheximide. While, the mycelial growth of other indicators such as Pyricularia oryzae, Sclerotium hydrophilum and some isolates of Rhizoctonia solani was not inhibited even at 100 μg/ml.
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  • Motoichiro KODAMA, Takuji YOSHIDA, Hiroshi OTANI, Keisuke KOHMOTO, Syo ...
    1991 Volume 57 Issue 5 Pages 663-670
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Effect of AL-toxin produced by Alternaria alternata tomato pathotype on viability of cultured cells derived from susceptible and resistant cultivars of tomato was examined. When calli of each cultivar were incubated on solid medium containing the toxin, cell browning occurred only on calli of susceptible cultivar within 3 days after the treatment. For quantitatively estimating the viability of toxin-treated cells, a colorimetric assay utilizing a tetrazolium salt, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), was employed. The number of living cells was proportional to the amount of formazan formed by reduction of MTT in active mitochondria, indicating that MTT-colorimetric assay should be useful for the quantitative determination of cell damage induced by the toxin. Formazan production in suspensioncultured cells of susceptible cultivar was inhibited by the toxin at about the same concentration as the minimum concentration for necrosis induction on leaves. In contrast, resistant cells were not affected significantly by the toxin even at higher concentrations. The MTT assay appeared to have some advantages over conventional techniques for evaluating the effect of toxin on cultured cells. Additionally, these results indicate that the host-selective toxicity of AL-toxin is expressed to the cultured cells as well as the plant tissues.
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  • Sung-Suk LEE, Takashi TSUGE, Noriyuki DOKE, Syoyo NISHIMURA
    1991 Volume 57 Issue 5 Pages 671-679
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    An assay system using strawberry cultured cells was established for assessing the biological activities of AF-toxins produced by Alternaria alternata strawberry pathotype, causal agent of Alternaria black spot of strawberry. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide]-colorimetric assay, in which cell viability was quantitatively determined by spectrophotometric measurement of cell extracts containing MTT-formazan generated in viable cells, was employed to assess the host-selective toxicity of AF-toxins to strawberry cultured cells. Cultured cells of three genotypes of strawberry, whose leaves are super-susceptible, susceptible and resistant to the pathogen and AF-toxin I, exhibited the same genotype-specific responses to AF-toxin I as their leaves. However., the sensiivity of susceptible cultured cells to the toxin was higher than that of their leaves: damage of the cultured cells was induced by the toxin treatment at much lower concentrations than was leaf necrosis. Protoplasts derived from their cultured cells also showed the similar reactions to the toxin. Experiments exposing cultured cells to AF toxin I for definite times demonstrated that a 2-min exposure of super-susceptible cells to the toxin apparently caused the cell damage, and that a 10-min exposure affected the cells as intensely as a 6-hr continuous exposure. These results indicate that a toxic quality can be absorbed or taken up in a relatively short time: continuous exposure of cells to the toxin is not necessary for causing cell damage.
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  • Tsuneo WATANABE
    1991 Volume 57 Issue 5 Pages 680-687
    Published: December 25, 1991
    Released: February 19, 2009
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    Seven isolates of three Sordaria species which were antagonistic to Armillaria mellea were selected as biocontrol agents, and tested against soilborne diseases, caused by Pythium aphanidermatum, and/or Dematophora necatrix, of cucumber, spinach, komatsuna, and Japanese black pine seedlings using the soil-over-agar-culture-inoculation methods under the growth chamber, and semi-field conditions. The effects of the antagonists were evaluated based on the emergence, and healthy seedling rates in the soil over the co-cultures of pathogen and antagonist in various combinations in plates, or in the artificially infested soils, directly applied by pouring potato dextrose broth cultures of antagonists or sowing the seeds treated with antagonists. Biocontrols of the soilborne plant diseases by Sordaria spp. were almost successful in any treatment in this study.
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  • Ana Paula Ayres BORDIN, Shigeyuki MAYAMA, Toshikazu TANI
    1991 Volume 57 Issue 5 Pages 688-695
    Published: December 25, 1991
    Released: February 19, 2009
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    Chitin, chitosan, oligo galacturonic acid, glucan and some of constituent monosaccharides were tested of their elicitor activities for avenalumin accumulation in oat leaves and a bioassay method for its elicitation was evaluated. Among the compounds tested, a water-soluble chitosan (DP: 37, acetyl, rate 39%) was the most potent elicitor, followed by chitin, glycol chitin, oligo galacturonic acid and glucan in the order. No accumulation of avenalumin I was elicited by aminosugar monosaccharides. Effects of the molecular size and acetylation rate of chitosan on elicitor activity were determined using chitosans with DPs 37, 10, 8 and 5, and acetylation rates 39, 30, 15 and 6%, respectively. All the chitosans were effective elicitors; however, the high molecular chitosan (DP: 37) seemed to be more active elicitor than the others especially at low concentrations. A significant finding was that the chitosans elicited a differential production of avenalumin I in oat cultivars of different genetic backgrounds. Certain cultivars such as Shokan-1 and Pc-51 were always sensitive to the chitosans and accumulated larger quantities of avenalumin, whereas a cultivar like Pc-45 accumulated only about 1/4 the amount in the sensitive cultivars. It was shown that infiltration of elicitor solutions into intercellular spaces of the primary leaves by hypodermic injection was found much more efficient for the assay of differential elicitor activity than the assay with epidermis-detached leaf segments.
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  • Tsutomu ARIE, Yoshio HAYASHI, Akira NAGATANI, Masaki FURUYA, Isamu YAM ...
    1991 Volume 57 Issue 5 Pages 696-701
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Stable hybridoma cell lines secreting monoclonal antibodies (MoAbs) to Fusarium oxysporum (860926a) were produced by fusing spleen cells from immunized BALB/c mice with SP2 myeloma cells. Antibody production by the cell lines, API9-2 and API9-3, was assayed by dot immunobinding assay (DIBA). These MoAbs showed positive reactions with 11 formae speciales (ff. sp.) of F. oxysporum, Gibberella fujikuroi (F. moniliforme), G. zeae (F. roseum), as well as with Nectria haematococca (F. solani). Whereas the MoAbs did not react with 35 plant pathogenic fungi, not classified in Fusarium spp. except N. solani (Thielaviopsis basicola). Thus these hybridoma-derived antibodies are considered to be specific to the genus Fusarium.
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  • Tomizo OHGUCHI, Yukio NAGAO, Katsuyuki YOSHIDA
    1991 Volume 57 Issue 5 Pages 702-705
    Published: December 25, 1991
    Released: February 19, 2009
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  • Nobuhiro SUZUKI, Yukio SHIRAKO, Yoshio EHARA
    1991 Volume 57 Issue 5 Pages 706-710
    Published: December 25, 1991
    Released: February 19, 2009
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  • Norio OHTSUKA, Yasuhiko NAKAZAWA, Osamu HORINO
    1991 Volume 57 Issue 5 Pages 711-715
    Published: December 25, 1991
    Released: February 19, 2009
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  • Hideyoshi TOYODA, Kazuhiko MATSUDA, Mitsue DOGO, Koji KAKUTANI, Keiji ...
    1991 Volume 57 Issue 5 Pages 716-719
    Published: December 25, 1991
    Released: February 19, 2009
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  • Jiro TOGASHI, Tsuneo NAMAI
    1991 Volume 57 Issue 5 Pages 720-723
    Published: December 25, 1991
    Released: February 19, 2009
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  • Yuichi TAKIKAWA, Shinji TSUYUMU, Masao GOTO
    1991 Volume 57 Issue 5 Pages 724-728
    Published: December 25, 1991
    Released: February 19, 2009
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  • Masayuki TOGAWA, Yuichi TAKIKAWA
    1991 Volume 57 Issue 5 Pages 729-731
    Published: December 25, 1991
    Released: February 19, 2009
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  • Wataru HASAMA, Suzumi MORITA, Tokuhiro KATO
    1991 Volume 57 Issue 5 Pages 732-736
    Published: December 25, 1991
    Released: February 19, 2009
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    A new disease of perilla (Perilla frutescens) broke out in Oita Prefecture in 1990. The symptoms of the disease appeared on leaves and stem as brown spot. Corynespora sp. was isolated from infected lesions. Conidia were hyaline to pale brown, obclavate to cylindrical, curved, broad at the base, formed on conidiophores singly or in chain. Conidiophores were pale to mid brown and erect. No stromata were observed. The optimum temperature of mycelial growth lied at 27.5-30°C. The fungus was pathogenic to 17 species including tomato, cowpea, sesame and others among 18 tested plants in inoculation experiments. Based on these morphological and pathological characters, the causal fungus was identified as Corynespora cassiicola (Berk. & Curt.) Wei by the similarity to the description of Ellis (1971).
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  • Shin'ichi KUSAKARI, Kiyotugu OKADA, Wataru NAKASONE, Yutaka TANAKA
    1991 Volume 57 Issue 5 Pages 737-740
    Published: December 25, 1991
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Leaf spot and leaf decay disease of perilla (Perilla frutescens) has been found on harvested perilla leaves at market of Osaka in summer season of 1990. The spots of perilla leaf were circular and black, sometimes leaves were decayed. Isolated fungi formed singly or in chains of conidia on an apex of conidiophore on perilla leaf. Conidia were straight to curved, cylindrical to obclavate. The isolated fungi infected soybean, lotus lily, eggplant, and several tropical plants which described in Wei's report. According to these characteristics, the fungus was identified as Corynespora cassiicola (Berk. & Curt.) Wei. We propose the name of Corynespora leaf spot disease of perilla.
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