Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 51 , Issue 2
Showing 1-19 articles out of 19 articles from the selected issue
  • Shiro KUNINAGA, Ryozo YOKOSAWA
    1985 Volume 51 Issue 2 Pages 127-132
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    DNA base sequence homology among isolates of different anastomosis groups (AG-1, AG-2, AG-3, AG-4, AG-5, AG-6 and AG-7) in Rhizoctonia solani was determined by DNA-DNA reassociation kinetics. DNA homology among isolates of these anastomosis groups showed consistently low values (0 to 33.7%). These results suggest that each of these anastomosis groups is a genetically isolated group. The significance of classification of R. solani into groups on the basis of anastomosis behaviours is stressed.
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  • Shiro KUNINAGA, Ryozo YOKOSAWA
    1985 Volume 51 Issue 2 Pages 133-138
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    DNA base sequence homology between isolates of AG-BI and other anastomosis groups in Rhizoctonia solani was determined by DNA-DNA reassociation kinetics. A comparatively high homology was observed between AG-BI and AG-2. AG-BI isolates showed 36.1 to 48.0% homology with isolate of AG-2-1 and 34.0 to 46.4% homology with isolates of AG-2-2. While, AG-BI isolates showed 18.7 to 30.2% homology with isolates in AG-3 and AG-6, but consistently low homology (0 to 14.4%) with isolates in the other anastomosis groups. These results suggest that AG-BI and AG-2 should not be considered as separate groups. The phylogenetical relationship between AG-BI and the groups of AG-2, AG-3 and AG-6 is discussed.
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  • Tsutomu SAKUMA
    1985 Volume 51 Issue 2 Pages 139-144
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Apple rust is incited by Gymnosporangium yamadae Miyabe ex Yamada, a demicyclic rust with some kinds of chinese juniper such as Juniperus chinensis L. and apple as alternate hosts. Seventeen fungal specimens were collected in 14 areas of Hokkaido and Honsyu islands. Two pathogenic races of the fungus were distinguished by inoculation of McIntosh, Empire and other five cultivars under the controlled conditions. All cultivars inoculated were susceptible to race 1. McIntosh and Empire (Delicious×McIntosh) were resistant to race 2. Only pycnium was incited on the lesions. These pathogenic races inoculated on J. chinensis showed the same reaction on the indicator cultivars after two years.
    Akane (Jonathan×Worcester pearmain) and Worcester pearmain showed a different resistance from that of cvs. McIntosh and Empire to race 2. No lesions were detected on either cv. upon field observation. When potted plants, cvs. Akane and Worcester pearmain grown under a screenhouse with glass roof, were inoculated under the controlled conditions (plants were kept 24hrs in a moist chamber at 17.5±1.5C), many small but clear lesions with aecia were incited by all fungal collections. On the other hand, lesions with aecia were rarely incited, when Akane was inoculated under the field conditions.
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  • Tsutomu SAITO
    1985 Volume 51 Issue 2 Pages 145-151
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In September 1982, an unknown bacterial wilt disease with brownish discoloured lower leaves was found on carnations growing in Shizuoka prefecture, Japan. In the diseased plants it was usually observed that the vascular tissues of a stem discoloured to brown and the roots were rotted. These symptoms developed over six months before infected plants were finally killed. The young shoots of artificially inoculated plants showed a peculiar appearance with extremely short internodes, but this symptom was not observed on naturally infected plants. The causal bacterium was identified as Erwinia chrysanthemi pv. dianthicola by its bacteriological properties and pathogenicity. This is the first record of bacterial stunt of carnation in Japan.
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  • Akira MATSUBARA, Makoto KOJIMA, Shinji KAWANO, Masaaki NARITA, Manami ...
    1985 Volume 51 Issue 2 Pages 152-158
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A Japanese isolate of barley yellow dwarf virus (BYDV) was purified from infected plants by an improved procedure. The procedure included extraction of the virus by grinding the frozen plant tissues in a meat grinder followed by regrinding in phosphate buffer with motar and pestle for extended periods (more than 2hr) in room temperature, clarification of the sap with chloroform, concentration of the virus by polyethylene glycol, two cycles of differential centrifugation and a sucrose density gradient centrifugation. The average yield of the virus was 44μg per 100g tissues. The Japanese isolate had particle diameter of 27.3nm (2% PTA, pH 5.0) and UV absorbance spectrum with an average A260/A280 ratio of 1.71. In ELISA using the double antibody sandwich method, the virus reacted only with homologous antiserum but not with antiserum to potato leafroll virus (PLRV), and vice versa. The virus, however, reacted slightly with heterologous antisera to other luteoviruses such as PLRV, soybean dwarf and beet western yellows viruses in agar gel double diffusion tests.
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  • Shigehiro KATO, Toshiro NAKANISHI, Yukiyoshi TAKAHI, Kazuto NAKAGAMI
    1985 Volume 51 Issue 2 Pages 159-167
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pythium spinosum, P. irregulare and P. sylvaticum were frequently isolated from diseased rice seedlings with symptom of root and stem rot. The disease was favored by low temperature at the early growth stage of rice seedlings grown in four different solis in nursery flats. In pathogenicity tests, all of the three Pythium species were strongly pathogenic to rice seedlings at emergence and produced symptoms similar to those characteristically seen in nursery flats, but were nonpathogenic to rice seedlings later than the first leaf stage. The severity of damping-off caused by the three Pythium species increased under low temperature of emergence time and on soil with a pH of 6. The additional pathogenicity tests also indicated that five other species (P. aphanidermatum, P. myriotylum, P. splendens, P. ultimum and P. vexans) from the different sources significantly reduced rice seedling emergence. From these results, P. spinosum, P. irregulare and P. sylvaticum are considered to be the causal agents of damping-off of rice seedlings grown in nursery flats. In addition, some other Pythium species appear to be involved in the rice seedling disease in nursery flats.
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  • Shigehiro KATO, Toshiro NAKANISHI, Yukiyoshi TAKAHI, Kazuto NAKAGAMI, ...
    1985 Volume 51 Issue 2 Pages 168-175
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pythium graminicola was predominantly isolated from diseased rice seedlings at the 2-3 leaf stage with symptom of acute wilt. The disease occurred at middle and latter growth stages of rice seedlings grown in three different soils in nursery flats. Pathogenicity studies indicated that P. graminicola produced acute wilt symptom on rice seedlings at the 2-3 leaf stage similar to that characteristically seen in nursery flats when rice seeds were sown in soil artificially infested with a small amount of hyphae of the fungus or when rice seedlings at the 2 leaf stage were inoculated with zoospores. In addition, P. graminicola caused pre-emergence seedling rot when rice seeds were sown in soil artificially infested with a large amount of hyphae of the fungus or when germinated seeds were inoculated with zoospores. From these results, P. graminicola is considered to be the causal agent of damping-off of rice seedlings in nursery flats.
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  • Hiroki KOGANEZAWA
    1985 Volume 51 Issue 2 Pages 176-182
    Published: April 25, 1985
    Released: February 19, 2009
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    Two species of low molecular weight RNA have been associated with apple scar skin disease. One of the RNAs, ASSARNA 1 was detected in the bark tissue as well as in the fruit tissue of diseased apple trees. Inoculation of young seedlings with extracted RNA was performed by rubbing with carborundum or by slashing with a razor. Nucleic acid was extracted from the bark of inoculated seedlings and analysed by two cycles of polyacrylamide gel electrophoresis. ASSARNA 1 was detected in one of 13 seedlings after 28 months following inoculation by the rubbing method with phenol-extracted nucleic acid and in 8 of 14 seedlings after 13 months following inoculation by the razor-slash method with purified ASSARNA 1. The results indicate that ASSARNA 1 was transmitted to apple seedlings and multiplied in them. These facts provided additional evidence for the viroid etiology of the causal agent of apple scar skin disease. However, the pathogenecity of ASSARNA 1 and the role of another disease-associated RNA, ASSARNA 2, are still unknown.
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  • Isao UNO, Tatsuo ISHIKAWA, Teruyoshi HASHIBA
    1985 Volume 51 Issue 2 Pages 183-189
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Rhizoctonia solani isolates capable of forming sclerotia accumulated two or three times higher amounts of adenosine 3', 5'-cyclic monophosphate (cAMP) in mycelial cells comparing with those incapable of forming sclerotia. The addition of adenine and L-cysteine to culture media was effective to inhibit formation of sclerotia. Adenine inhibited adenylate cyclase activity, but not phosphodiesterase activity. L-cysteine showed no effect on both adenylate cyclase and phosphodiesterase activities. A single cAMP-receptor protein was detected by photoaffinity labeling with 8-N3-cAMP in mycelial extracts of all isolates of R. solani tested. The protein had an apparent molecular weight of 50, 000 and co-chromatographed on a DEAE-Sephacel column with cAMP-dependent protein kinase. The result indicated that the 50, 000-dalton protein may be a regulatory subunit of protein kinase with capacity to bind cAMP.
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  • Isao UNO, Tatsuo ISHIKAWA, Teruyoshi HASHIBA
    1985 Volume 51 Issue 2 Pages 190-198
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The phosphorylation of three cellular proteins from mycelia of Rhizoctonia solani was stimulated in the presence of adenylate 3', 5'-cyclic monophosphate (cAMP). The molecular weights of these proteins were determined to be 25, 000, 32, 000 and 62, 000 by gel electrophoresis in the presence of SDS. One of them (62K protein) was phosphorylated in the presence of cAMP to the maximal level within 5min, and the ATP concentration was saturated for the phosphorylation of this protein at 20μM. The Ka value for cAMP in the phosphorylation of 62K protein was approximately 0.1μM. NAD-dependent glutamate dehydrogenase activities in crude extracts of R. solani mycelia that form sclerotia in the presence of cAMP were inhibited significantly by preincubation with both ATP and cAMP. The inhibition of this enzyme activity saturated at 20μM ATP. The Ki value for cAMP on the inhibition of NAD-dependent glutamate dehydrogenase activity was approximately 0.1μM. These results suggest that inhibition of NAD-dependent glutamate dehydrogenase in R. solani mycelia is regulated by phosphorylation through activation of cAMP-dependent protein kinase.
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  • Takuji KOZAKA, Makoto TSUCHIZAWA, Masami HANAUE, Minoru WATANABE
    1985 Volume 51 Issue 2 Pages 199-205
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Cultures of Pyricularia oryzae Cav. produce an extracellular phytotoxic glycopeptide capable of inciting white head symptoms quite similar to those of neck-rot blast at the concentration above 62.5ppm. After removing impurities with organic solvents, the toxin was purified from the culture filtrate by Sephadex G-100 column chromatography followed by Avicel® column chromatography. The purified toxin consisted of fifteen common amino acids with serine and threonine as major amino acids, and two hexoses, glucose and mannose. The estimated molecular weight was about 30, 000. The toxin was water soluble and heat-stable. Anatomical examination of rice stem treated with the toxin revealed obvious blockage of the vascular system due to an occlusion of the vessels, particularly in the nodes. The toxin showed no race specificity.
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  • Tsuneo NAMAI, Susumu YAMANAKA
    1985 Volume 51 Issue 2 Pages 206-211
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The occurrence of variants and change of predominant race of rice blast fungus, Pyricularia oryzae Cavara, during successive inoculation on rice plants were investigated using two isolates (race 337) which have wide spectrum of virulence and always sorted out some variants. Thus, the isolates were passed through the leaves of 6 susceptible rice varieties for 9 successive generations by punch-inoculation in a growth cabinet. In 4 among 12 combinations of 2 isolates and 6 rice varieties, predominant race changed until the 9th generation. On two varieties, Aichiasahi and Fujiminori with vartical blast resistance gene Pi-a, race 003 became predominant replacing the races 337 and 137 in 3 cases out of 4. Race 047 survived on Ishikari-shiroke with resistance gene Pi-i until the 9th generation. On the other hand, predominant race did not change in all combinations on Fukuyuki with resistance gene Pi-i and Kanto 51 and Kusabue with resistance gene Pi-k until the 9th generation.
    These data suggested that race 337 sorted out many variants during the successive passage on rice leaves and some of the variants, race 003 or 047, survived and predominated in competition with others.
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  • Hirotaka KUWATA
    1985 Volume 51 Issue 2 Pages 212-218
    Published: April 25, 1985
    Released: February 19, 2009
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    The occurrence of a new bacterial disease, halo blight, has recently been recorded on rice plants (Oryza sativa L.) in several districts of Aomori Pref., Japan. The disease is characterized by small brown lesions surrounded by a large and yellow halo on the leaf blades. A comparative study of the causal agent indicated that as a whole the bacteriological characteristics of the present bacterium is identical with those of Pseudomonas syringae pv. atropurpurea and P.s. pv. coronafaciens which also produce halo blight on various gramineous plants. In addition to rice plants, the present bacterium was also pathogenic to Hordeum vulgare, Avena sativa and Phaseolus vulgaris, inducing similar symptoms. However, P.s. pv. atropurpurea and P.s. pv. coronafaciens were not pathogenic to rice plants. From these characteristics it was concluded that the present bacterium is a new pathovar of P. syringae, and the name P. syringae pv. oryzae n. pv. was thus proposed.
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  • Ryutaro SAKAI, Yosuke MINO, Akitami ICHIHARA, Sadao SAKAMURA
    1985 Volume 51 Issue 2 Pages 219-222
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Yukio TOSA, Kazuyuki MISE, Jiko SHISHIYAMA
    1985 Volume 51 Issue 2 Pages 223-226
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Keiji MAEKAWA, Mamoru HORIKOSHI, Iwao FURUSAWA
    1985 Volume 51 Issue 2 Pages 227-230
    Published: April 25, 1985
    Released: February 19, 2009
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  • Masao GOTO, Tsutomu SAITO, Yuichi TAKIKAWA
    1985 Volume 51 Issue 2 Pages 231-233
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A severe disease of unknown cause had been observed the past 15 years on bird-of-paradise (Strelitzia reginae Banks) grown under vinylhouse conditions in Izu peninsula of Shizuoka Pref., Japan. The etiological study of the disease revealed that it was bacterial wilt caused by Pseudomonas solanacearum which was first reported in Hawaii in 1963. First symptoms were curling upward of fully expanded leaves accompanied by yellow to orange discoloration. These leaves and leaf petioles gradually shriveled and finally dried up. The bacterium was virulent to Musa basjoo (diploid banana), but not to M. paradisiaca (triploid banana) and Heliconia psittacorum, indicating that it is belonged to race 1. The bacterium was characterized by a weak virulence to tomato in low temperature of 15 to 25C. Bacteriological properties of the bacterium were identical with those of biovar III.
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  • Yoshihiro OHTSU, Nobumichi SAKO, Susamto SOMOWIYARJO
    1985 Volume 51 Issue 2 Pages 234-237
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Zucchini yellow mosaic virus (ZYMV) was isolated from Cucurbita maxima (cv. Ebisu) cultivated in Okinawa prefecture. The isolates were mechanically transmitted to 15 plant species belonging to 5 families, causing systemic infections in all cucurbitaceous species tested, and nonpersistently transmitted by Myzus persicae and Aphis gossypii. Filamentous particles (700-800nm long) were found in both leaf extracts and purified preparations. The isolates reacted with ZYMV antiserum from Italy in immunoelectron microscopy and SDS-immunodiffusion test.
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  • Kouji YOSHIDA, Tadanori GOTO, Norio IIZUKA
    1985 Volume 51 Issue 2 Pages 238-242
    Published: April 25, 1985
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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