Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 78, Issue 2
Displaying 1-5 of 5 articles from this issue
Originals
  • Y. SHIMOMOTO, H. SAWADA, M. OKADA, Y. MORITA, H. MIZUMOTO, A. KIBA, Y. ...
    2012 Volume 78 Issue 2 Pages 85-91
    Published: 2012
    Released on J-STAGE: June 01, 2012
    JOURNAL FREE ACCESS

    Corynespora blight caused by Corynespora cassiicola has spread through western Japan, leading to massive losses in sweet pepper production. In this study, to select plants resistant to Corynespora blight, we first inoculated 13 commercial cultivars and four mother lines of Capsicum plants with C. cassiicola. None of these plants were resistant to Corynespora blight. Of 38 breeding lines of Capsicum that were inoculated with C. cassiicola, five lines expressed a resistance to Corynespora blight that was highly variable among plants of the same line. Fourteen new lines were developed from the four resistant lines using anther culture. These anther-culture lines were highly resistant to the disease. From four anther-culture lines with higher resistance compared to other lines, self-cross breeding lines were produced. The self-cross breeding lines had high resistance to Corynespora blight, the same as the anther-culture lines. Thus, these self-cross breeding lines should be useful as mother lines for breeding new cultivars of C. annuum resistant to Corynespora blight.
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  • T. MIYOSHI, S. SHIMIZU, H. SAWADA
    2012 Volume 78 Issue 2 Pages 92-103
    Published: 2012
    Released on J-STAGE: June 01, 2012
    JOURNAL FREE ACCESS
    In Ehime Prefecture, Japan, two types of symptoms of bacterial canker on kiwifruit have been found, subsequently termed types A and B. Type A symptoms, which formed on leaves in orchards located in Iyo City, are characterized by typical lesions (leaf spots with clear yellow halos). Type B symptoms, observed on leaves in orchards in Matsuyama City and Tobe Town, include only necrotic lesions without halos. Based on genotypic and phenotypic characterizations, the pathogens isolated from the two groups of orchards were both identified as Pseudomonas syringae pv. actinidiae (Psa). In bioassay and inoculation experiments, the isolates derived from type B did not possess the ability to either produce phaseolotoxin (Ptx) or induce halos on kiwifruit leaves, although the constituent genes (amtA, ptx, ORF3 and argK) of the argK-tox cluster, which is responsible for Ptx production, were detected in these isolates by PCR. Although the coronatine-producing gene (cfl) and the effector gene (hopA1) have been reported in Psa isolated in Korea and Italy/France, respectively, we detected neither of these genes using PCR. These results suggest that a mutation(s) may have impaired Ptx production in Ptx-producing Psa, which is distributed widely in Japan, leading to the non-Ptx-producing mutant. We confirmed that such mutants are distributed exclusively in the Matsuyama-Tobe area in Ehime Prefecture, whereas Ptx-producers are prevalent in Iyo City. In addition, disease surveillance and inoculation experiments indicated that the virulence of the defective non-Ptx-producing mutant on kiwifruit branches was weaker than that of the Ptx-producers, suggesting that Ptx may function as a virulence determinant in branches.
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Short Communications
  • S. HASHIMOTO, I. KAWAMURA, M. NAKAJIMA, K. AKUTSU
    2012 Volume 78 Issue 2 Pages 104-107
    Published: 2012
    Released on J-STAGE: June 01, 2012
    JOURNAL FREE ACCESS
    The efficacy of Bacillus subtilis var. natto, a beneficial food microbe, was tested as a control for gray mold of strawberry. When five isolates of Bacillus subtilis var. natto were cultured with the gray mold fungus on potato sucrose agar plates, all isolates inhibited fungal growth. Isolate No. 2, which was the most inhibitory of the fungus in vitro, reduced disease progress in both detached leaves and flowers. These results suggest that isolate No. 2 of B. subtilis var. natto has potential as biological control agent of gray mold of strawberry plants.
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  • N. FURUYA, S. KAWANO, K.T. NATSUAKI
    2012 Volume 78 Issue 2 Pages 108-110
    Published: 2012
    Released on J-STAGE: June 01, 2012
    JOURNAL FREE ACCESS
    In an evaluation of the susceptibility of three Musa species grown in Okinawa Island, Japan, to Banana bunchy top virus (BBTV), the virus was widely distributed among edible banana cv. Dwarf Cavendish and cv. Shima. However, bunchy top symptoms and BBTV infection were not observed and detected from all plants of fibre banana cv. Itobasho (Musa balbisiana var. liukiuensis) tested. Furthermore, none of the Itobasho plants were infected with BBTV via viruliferous banana aphids (Pentalonia nigronervosa Coq.) that had been propagated on BBTV-infected pseudostems, whereas 78% of the edible bananas were infected under the same conditions. Thus, Itobasho seems to have an immunity to BBTV but is not resistant to aphid infestation or colonization.
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  • H. YAMAMOTO, M. SENDA
    2012 Volume 78 Issue 2 Pages 111-113
    Published: 2012
    Released on J-STAGE: June 01, 2012
    JOURNAL FREE ACCESS
    In 2009, Asiatic hybrid lily plants with mosaic symptoms were observed in Akita Prefecture, Japan. In a RT-PCR assay, using universal primers for the detection of potyviruses, a potyvirus different from Lily mottle virus was detected. The conserved area of the virus coat protein (CP) shared the highest amino acid (aa) sequence similarity (95.7%) to that of Rembrandt tulip breaking virus (ReTBV). As far as we know, this report is the first on the occurrence of ReTBV in Japan and on the full aa sequence of the CP for this virus.
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