Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 46 , Issue 5
Showing 1-17 articles out of 17 articles from the selected issue
  • Yutaka ARIMOTO, Yasuo HOMMA, Tomomasa MISATO
    1980 Volume 46 Issue 5 Pages 575-581
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pycnospore germination of Diaporthe citri (Faw.) Wolf and its hyphal penetration to host plant (Citrus unshiu) began 5 hr and 8 hr after inoculation, and reached maximum level 10 hr (15%) and 12 hr (7%) after inoculation respectivery. On the lower leaf surface, hyphal penetration occurred through stomata (67%) or cuticle (33%). Penetration trace on the leaf surface was observed as being a hall by etching with ion beam. Sarrowndings of the trace was specifically stained with basic fucsin. On the upper leaf surface, the hyphae penetrated to cuticle layer just above epidermal suture (40%) and of another portion of epidermal cell (60%). After penetrating into cuticle layer, subcuticle hyphae was formed between cuticle layer and epidermal cell wall. The hyphae did further penetrated into cell wall of epidermal cell, and elongated along the cell wall to epidermal suture. After being elongation, the hyphae reached to inside of epidermal cell from suture of epidermis. Most of invaded hypha died in the cell wall, suture and cell of epidermis. These results suggested that an inhibitor (s) against growth of D. citri might be present in the host tissue.
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  • Shigehisa KIYOSAWA
    1980 Volume 46 Issue 5 Pages 582-593
    Published: December 25, 1980
    Released: February 19, 2009
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    The ratio of observed value to expected value of genotype Av-i+ Av-k+ for virulence in blast fungus (abbreviated as + + genotype ratio) was studied using the available data in Japan. The + + genotype ratios were higher than one in almost all years in all ten districts. The + + genotype frequencies decreased during seven years from 1959 to 1965, with decrease of frequencies of individual virulence genes, Av-i+ and Av-k+, except Hokkaido. In Niigata, Toyama, Yamagata and Kanagawa Prefectures, significant differences are found between expected and observed values in various genotypes for virulence during the period from 1964 to 1966. The results of simulations and mathematical analysis on the change of + + genotype ratio indicate that the + + genotype ratio becomes temporarily higher than one when p2r2p3r3/p1r1p4r4<Q4/(Q2+Q4)(Q3+Q4) and lower than one when p2r2p3r3/p1r1p4r4>Q4/(Q2+Q4)(Q3+Q4). The + + genotype ratio asymptotically approaches to 1 under conditions where the frequency of + + genotype continues to increase and to 0 when it continues to decrease. The change of frequencies of + + genotype (race) cannot be explained by simple directional and stabilizing selections. The + + genotype ratio returns to 1 even after directional and/or stabilizing selections, and this limits the use of virulence analysis to search for the causes of the change of pathogen genotype (race) frequencies. The ratio of observed value to expected one in various genotypes (especially + + genotype) may help the studies in a sense that the use of the ratio reduces the range or kinds of factors which must be examined.
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  • Nobuhiro KITA, Hideyoshi TOYODA, Tetsuo YANO, Jiko SHISHIYAMA
    1980 Volume 46 Issue 5 Pages 594-597
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In susceptible barley to Erysiphe graminis f. sp. hordei race I, the relation between fluorescent appearance in papilla and fungal penetration attempts was examined using light and fluorescent microscope. In the primary penetration course, fluorescent appearance was detected in all papillae where inoculated conidia ceased the penetration into host epidermal cells, whereas the papillae which permitted the successful penetration attempts did not show any fluorescent appearance. In halo, the same fluorescent appearance was observed regardless of success or failure of fungal penetration. These cytological responses were also observed in the secondary or tertiary penetration sites 72hr after inoculation. These results suggested that accumulation of fluorescent compound in papilla was essential for the prevention of fungal penetration in powdery mildew of barley.
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  • Tsuneo WATANABE
    1980 Volume 46 Issue 5 Pages 598-606
    Published: December 25, 1980
    Released: February 19, 2009
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    A new variety of Verticillium sphaerosporum Goodey isolated from conidia produced on dead nematodes on water agar originally plated with decaying strawberry root tissues, showed endoparasitic effects against some nematodes tested, including Aphelenchoides, Cephalobus, and Panagrolaimus sp. This fungus in dual culture on potato-dextrose agar with each of 91 isolates of various soil-borne plant pathogens and saprophytic soil fungi caused more than 50% inhibition of radial mycelial growth in Alternaria sp., Phoma sp., Pithomyces sp., Pythium splendens, P. sylvaticum, Rhizoctonia solani, and Trichocladium sp.
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  • Katsuto KUNIYASU
    1980 Volume 46 Issue 5 Pages 607-614
    Published: December 25, 1980
    Released: February 19, 2009
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    The distribution of the causal fungus, Fusarium oxysporum f. sp. lagenariae Matuo et Yamamoto, in the vascular bundles of the loculus and placenta as well as seed coats of infected fruits was studied with the aim of tracing the direct invasion through the vascular bundles to the seeds. The infected fruits which were borne on diseased stems and did not show any decay of tissues but showed discoloration of the principal vascular bundles in the epicarp caused by the causal fungus penetration were used as materials for the observations. Presence of the causal fungus in the loculus and the placenta was confirmed by placing the tissue sections on solid Komada's medium, a selective medium for quantitative isolation of Fusarium oxysporum, and observing the development of the causal fungus. A distinct vascular bundle extending from the hilum through the raphe was observed in the seed coats. This bundle is known to be one of the anatomical features of the seeds developed from anatropous ovules such as the seeds of bottle gourd. Out of about 1000 seeds harvested from the infected fruits mentioned above, 23 seeds were proved to be infected with the causal fungus. In 6 seeds among the infected seeds, chlamydospores which presumably had originated from the causal fungus were observed in the vessels and in the parenchyma tissues of vascular bundles of the seed coats. Their diameter was 7.6μm in average. While the diameter of the chlamydospores of the causal fungus cultured on apricot medium was 7.5μm. Thus both chlamydospores showed nearly identical shape and diameter. The chlamydospores in the seed coats germinated when the infected seeds were incubated on Komada's medium at 25 C for 24hr. The results mentioned above suggested the possibility of direct invasion of the seeds by the causal fungus through the vascular bundles.
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  • Kuniyuki MIYAJIMA, Kazuo TSUBOKI
    1980 Volume 46 Issue 5 Pages 615-622
    Published: December 25, 1980
    Released: February 19, 2009
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    In 1978, bacterial streak of smooth bromegrass caused by Xanthomonas campestris pv. cerealis (Hagborg 1942) Dye 1978 occurred in Hokkaido, Japan. The lesions on the leaves were at first water-soaked, dark-green spots limited by the veins and gradually became elongate in interveinal parenchyma to form streaks. Later the lesions became translucent black streaks. The surface of the streaks was often covered with milky droplets of bacterial exudate under humid conditions and with thin, transparent and dried films of exudates under dry conditions. Typical symptoms were produced on smooth bromegrass, mountain bromegrass, quack grass, barley, rye, wheat and oats, but not on orchardgrass, timothy or rice by artificial inoculation. The bacteriological characteristics of the pathogen were determined: Cells were non-spore-forming rods with a single flagellum, Gram-negative and aerobic. Yellow pigment and slime were produced on nutrient glucose agar. Catalase and lecithinase reactions were positive, but Kovacs' oxidase, urease and tyrosinase were negative. Glucose was oxidatively metabolized. H2S and ammonia were produced, but not 2-ketogluconate, indole or acetoin. Aesculin, Tween-80 and starch were hydrolysed, but not margarine or sodium hippurate. Gelatin was liquefied, and nitrate was not reduced. Growth on nutrient agar was inhibited by 0.1% TTC. Asparagine was inadequate as a sole source of carbon and nitrogen. Acid was produced from arabinose, xylose, glucose, fructose, galactose, mannose, sucrose, glycerol, cellobiose and trehalose, but not from rhamnose, maltose, lactose, raffinose, inulin, salicin, mannitol, sorbitol, adonitol, dulcitol or inocitol. Acetate, citrate, malate, succinate and lactate were utilized but not benzoate, oxalate or tartrate.
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  • Minoru WATANABE, Shin-ichi SAMEJIMA, Daijiro HOSOKAWA
    1980 Volume 46 Issue 5 Pages 623-627
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Accumulation of 14C-photosynthetic assimilates in rice leaves infected with Xanthomonas campestris pv. oryzae was studied by using autoradiography for the purpose of elucidating the movement of nutrients from healthy tissues to the infected parts. When rice plants were exposed to 14CO2 immediately after inoculation, 14C-photosynthetic assimilates did not accumulate in and around the inoculated spots of leaves until the lesions became visible, i. e., approximately 7 days after inoculation. When the leaves were exposed to 14CO2 before visible lesions appeared, 2 and 5 days after inoculation, the assimilates did not accumulate in the inoculated areas, but apparently accumulated in the lesions 24 hr later on from the exposure of leaves with visible lesions. In the newly formed lesions, accumulation site corresponded to the yellow streak parts of lesions along leaf veins. In the large and old lesions, assimilates hardly any accumulated in the center of lesions, grayish-white in color, but accumulated in the border parts of lesions adjacent to healthy tissues which are developing and yellow streak in symptoms.
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  • Takeshi TANIGUCHI
    1980 Volume 46 Issue 5 Pages 628-633
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Seed extracts of Dianthus barbatus L. inhibited the development of local lesions induced by tobacco mosaic virus-ordinary strain (TMV-OM) and potato virus X (PVX) on Chenopodium amaranticolor Coste et Reyn. when mixed with the inocula. The extracts prevented infection of Samsun NN tobacco and French bean by TMV-OM when applied within 3 days before or within 3 hours after application of TMV-OM inocula. The extracts also showed virus inhibition when they were applied to the lower surface of leaves of Samsun NN tobacco and French bean and then TMV-OM was applied to the upper surface. The inhibitory activity could be separated into 3 distinct substances by gel-filtration chromatography on a column of Sephadex G-25. Strong inhibitory activity was observed in the substance of high molecular weight. A purification procedure of the inhibitive substance will be reported in the next paper.
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  • Wang-ching Ho, Wen-hsiung Ko
    1980 Volume 46 Issue 5 Pages 634-638
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Most media developed for enumerating soil actinomycetes do not prevent the growth of bacteria. When the pH of water agar was adjusted to 10.5, more than 90% of bacterial colonies from natural soil were suppressed, whereas the number of actinomycete colonies remained constant. All six species of bacteria tested were completely or nearly completely inhibited in alkaline water agar, whereas, colony development of all six actinomycetes was not affected. When water agar was used the numbers of actinomycetes from soil amended with glucose or alfalfa meal were very difficult to count because of the presence of numerous bacteria. In alkaline water agar more than 99.9% of bacteria were suppressed, and the numbers of actinomycetes were easily determined.
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  • Nobumichi SAKO, Kazutoshi MATSUO, Fukuji NONAKA
    1980 Volume 46 Issue 5 Pages 639-646
    Published: December 25, 1980
    Released: February 19, 2009
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    A purification procedure for watermelon mosaic virus (WMV) was developed. After initial clarification of expressed infected pumpkin leaf sap with 15% carbon tetrachloride in 0.3M potassium phosphate solution containing 0.01M DIECA, 0.1% ME, pH 8.8, addition of 2% Triton X-100 to the extract was effective for the removal of green host materials. WMV was concentrated by two cycles of differential centrifugation utilizing 20% sucrose cushion and further purified by rate zonal sucrose density gradient centrifugation. The ultraviolet absorption spectrum of the purified WMV preparation was typical of other potyviruses with a maximum at 260nm and a minimum at 246nm. The yield of purified WMV was 2 to 3.5mg per 100g of infected pumpkin leaves. Precipitation with polyethylene glycol MW 6, 000 (PEG) was not advisable, because of close aggregation of WMV particles, difficulty of subsequent dispersion, and greatly reduced yield. Enzyme-linked immunosorbent assay was found to be a rapid and valuable technique for comparing the various methods in each step of the purification procedure.
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  • Nobumichi SAKO, Kazutoshi MATSUO, Fukuji NONAKA
    1980 Volume 46 Issue 5 Pages 647-655
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The enzyme-linked immunosorbent assay (ELISA) provided a rapid and accurate method for detecting watermelon mosaic virus (WMV) and cucumber mosaic virus (CMV) in leaf extract and purified virus preparations from cucurbitaceous plants, pumpkin and cucumber. The reaction was specific enough to distinguish WMV and CMV even when the plants were infected doubly with the two viruses. ELISA was sensitive in detecting WMV and CMV in various parts, cotyledons, leaves, hypocotyls, and roots from plants 1 week after mechanical inoculation with crude extracts. The virus antigens in leaf disks dessicated with CaCl2 could be preserved and was easily detected with high ELISA absorbance values even at 30 C at least for 180 days' storage for WMV and over a storage period of 90 days for CMV. The possible application of the technique, together with dehydrated infected tissues for routine large scale diagnosis of WMV and CMV is discussed.
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  • Minoru WATANABE, Shin-ichi SAMEJIMA, Nobuo HAYASHI, Daijiro HOSOKAWA
    1980 Volume 46 Issue 5 Pages 656-662
    Published: December 25, 1980
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    The translocation and accumulation of 14C-photosynthetic assimilates in rice plants infected with Xanthomonas campestris pv. oryzae were investigated. Approximately the same quantities of assimilates were detected in healthy and infected leaves 1 day after photosynthesis, but 1.7 times as much as healthy leaves assimilates were still remained in infected leaves 7 days after photosynthesis. Much more 14C-photosynthetic assimilates were generally detected in leaf blade than in leaf sheath or in root within 1 day after photosynthesis, but detected in leaf sheath than in leaf blade later than 2 days after photosynthesis. The rates of translocation of 14C-assimilates from leaf blade to leaf sheath were lower in inoculated rice plants than in healthy ones. In both healthy and inoculated leaves of susceptible and resistant cultivars, there was a tendency that 14C-sugar contents decreased, but 14C-organic acid and -amino acid contents increased gradually after photosynthesis. Incorporation of 14C-photosynthetic assimilates into invading bacterial cells which were separated from leaf tissues by the methods of leakage and Millipore filtration was not detected immediately after photosynthesis, but became apparent 5 days after photosynthesis. The leakage of 14C-photosynthetic assimilates from leaf tissues into bathing solution was about 4 times higher in infected leaves than in healthy ones 5 days after photosynthesis, suggesting that the permeability in infected leaf tissues would increased.
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  • Takahito NODA, Zenji SATO, Hisayoshi KOBAYASHI, Shigeo IWASAKI, Shigen ...
    1980 Volume 46 Issue 5 Pages 663-666
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Seven toxic substances to rice seedlings were isolated from the cultured cell suspension of X. campestris pv. oryzae and they were identified as 3-methylthiopropionic acid, trans-3-methylthioacrylic acid, phenylacetic acid, isovaleric acid, tiglic acid, succinic acid and fumaric acid by means of UV-, IR-, NMR- and Mass-spectroscopy and of elementary analysis.
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  • Katsumi AKUTSU, Yoji DOI, Kiyoshi YORA
    1980 Volume 46 Issue 5 Pages 667-671
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Joon Tak LEE, Shuichi YAMASHITA, Yoji DOI, Kiyoshi YORA
    1980 Volume 46 Issue 5 Pages 672-676
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Mosaic plants of perilla were collected in Tokyo and Saitama prefecture. Virus particles detected in the diseased leaves were flexuous rods, about 13×760nm, with a helical symmetry of 3.4nm pitch. In ultrathin sections of the diseased leaves, the virus particles and cytoplasmic inclusions such as pinwheels and bundles were observed in the cytoplasm of virus-infected cells. By sap inoculation, the virus produced chlorotic local lesions on Chenopodium amaranticolor, C. quinoa, Gomphrena globosa, and Vicia faba, while it produced systemic mottling on Perilla frutescens var. acuta. The virus was also transmitted in a non-persistent manner by Myzus persicae (Sulz.). The virus was tentatively named perilla mottle virus.
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  • Susumu YAMANAKA, Soo Woong KANG
    1980 Volume 46 Issue 5 Pages 677-678
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    One isolate (Naga 64-8) among rice blast fungi (Pyricularia oryzae Cavara) isolated in Japan formed a very few susceptible lesions on Milyang 23 and Yushin of the Tongil variety group of Korean rice. All the reisolates from their lesions were severely pathogenic against the two Tongil varieties. On the other hand, reisolates from the lesions on Japanease rice varieties inoulated by the isolate of Naga 64-8 and those from the spores of the isolate on an oat-meal decoction agar medium contained both the pathogenic and the nonpathogenic isolates against the Tongil varieties. All their isolates showed the same reactions to the Japanease differentials as the isolate of Naga 64-8. The above results showed that the mother isolate of Naga 64-8 (033) contained two types of spores differing in pathogenicity against the Tongil varieties. Thus, we presumed that the isolate pathogenic against the Tongil varieties might sort out during successive culturing of the fungus by mutation.
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  • Hironori KOGA, Takashi KOBAYASHI
    1980 Volume 46 Issue 5 Pages 679-681
    Published: December 25, 1980
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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