Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 44 , Issue 2
Showing 1-17 articles out of 17 articles from the selected issue
  • Hironori KOGA, Shigeyuki MAYAMA, Jiko SHISHIYAMA
    1978 Volume 44 Issue 2 Pages 111-119
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The details of the primary infection process of E. graminis hordei on barley leaves was observed. No difference was observed before maturation of appressoria between compatible and incompatible host-parasite combinations, but the differnce became appararent at the stages of fungal penetration as reflected on subsequent haustorium formation and colony development by succeeded conidia. Most of the parasite units in the compatible combinations developed synchronously, while those in the incompatible ones did not. More than 80% of parasite units in the latter combinations ceased growth at the stage of papilla formation. It was recognized that the more resistant the host is the more conidia failed to penetrate at the stage of papilla formation. Close examination of fungal growth on different cultivars and variance analysis of individual colonies indicated that the extent of formation of collapsed mesophyll cells (CMC) could hardly be causally related to resistance. However, the rapidity of CMC formation seemed to be correlated with the strength of resistance as assessed by the final infection type, although the correlation did not become significant until 30hr after inoculation. It was suggested that a mechanism determining the disease specificity functions in the initial phase of penetrating stage of the mildew fungus and before the appearance of mesophyll cell collapse.
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  • Takao GOTO, Takeshi TANIGUCHI
    1978 Volume 44 Issue 2 Pages 120-126
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Protein and nucleic acid metabolisms in tobacco mosaic virus-infected Nicotiana glutinosa leaves were investigated. The plants were incubated at 32C for 2 or 3 days after inoculation with tobacco mosaic virus to establish a systemic infection and then some of these infected plants were transferred to 25C to induce local lesions and the others were kept 32C as controls. The leaves of each plant were detached and labeled by 14CO2. The supernatant fraction (S), mainly soluble proteins, obtained from the sap of the leaves by ultracentrifugation (105, 000×g) and the SDS-solubilized fraction (PS), mainly particulate-bound proteins, of precipitates at 10, 000×g, were electrophoresed on polyacrylamide gel columns. No difference in the proportion of protein was detected in both S and PS fractions between control and shifted plants. The incorporation of 14C from 14CO2 into the pellet fraction (P) at 105, 000×g, virus fraction, was reduced by the temperature shift. Methylated albumin kieselgur column chromatography of nucleic acid fractions obtained by phenol-SDS method showed that no significant change occurred in the proportion of molecular species of nucleic acids after temperature shift.
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  • Akira SHIRATA, Kohei TOMIYAMA, Noriyuki DOKE, Kokichi TAKAHASHI
    1978 Volume 44 Issue 2 Pages 127-136
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Activity of peroxidase in cut surface tissue of wound made in the bark of mulberry shoots increased almost immediately (within 1min) after cutting, accompanied by a decrease in activity in tissues next to the cut surface. This sudden change in peroxidase activity was found to be due to peroxidase contained in latex which flowed out from laticifers in the tissue next to the cut surface. Later increase in peroxidase activity in the tissue neighbouring wound, however, was found to be due to de novo synthesis of protein since blastcidin S (Bc S), an inhibitor of protein synthesis, inhibited the increase. Browning of the bark segments cut from the shoots was also inhibited by treatment with Bc S. The pattern of increase in peroxidase activity in the tissue neighbouring wound of shoots was altered when they were infected with Stigmina mori and Diaporthe nomurai. The highest peaks of peroxidase- and polyphenoloxidase-activities were then formed in the border part of the disease lesion. Four bands A-1, A-2, A-3 and A-4 were found by the gel isoelectric focusing on peroxidase activities of extracts obtained from mulberry shoots infected by Fusarium solani and D. nomurai. With latex secreted from wound, the bands A-2, A-3 and A-4 were founds. In the case of the healthy tissue two bands A-2 and A-3 were distinct. Phytoalexin like substances were found in the bark tissue infected by S. mori, D. nomurai and F. solani.
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  • Tsugufumi OGAWA, Tadashi MORINAKA, Keishi FUJII, Toshihiko KIMURA
    1978 Volume 44 Issue 2 Pages 137-141
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The inheritance of the resistance of rice varieties Kogyoku and Java 14 to bacterial group V of Xanthomonas oryzae was studied.
    From F2 data of five hybrids, Kinmaze×Kogyoku, Kinmaze×Java 14, Java 14×Kogyoku, Wase Aikoku 3×Kogyoku and Wase Aikoku 3×Java 14, it was revealed that the resistance of Kogyoku to bacterial group V was governed by one dominant gene, which was designated as Xa-kg, and that the resistance of Java 14 to the group V was also governed by Xa-kg or another dominant gene allelic to Xa-kg or linked very closely with it.
    Evidence from allele tests with the known genes, Xa-1 and Xa-w, for resistance to X. oryzae indicated that Xa-kg was independent of Xa-w and closely linked with Xa-1, and the recombination value between Xa-1 and Xa-kg was calculated at about 2%.
    It was further revealed that the resistance of Java 14 to X. oryzae was controlled by three dominant genes, Xa-1, Xa-w and Xa-kg, or other three genes allelic to these genes of linked very closely with them.
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  • Mas SUDJADI, Tadaoki INABA, Toshihiro KAJIWARA
    1978 Volume 44 Issue 2 Pages 142-150
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Histopathological studies on the corn plants inoculated with Sclerospora maydis were carried out to confirm the existence of the fungus in the apical meristem in relation to the systemic infection of the host plant. The hyphae were found in the central meristem of the shoot tip 20 days after inoculation. The hyphae were detected in every part of the corn shoot except for the apical meristem (in a narrow sense) but not in the root. The hyphae consisted of two types: slender and crooked hyphae. The slender hyphae were found in every infected tissue, and the crooked hyphae were observed only in the tissue of the expanded leaf showing systemic symptoms. Intercellular spaces of the diseased tissues in the expanded leaf were mostly occupied by crooked hyphae.
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  • Toshihiro OMURA
    1978 Volume 44 Issue 2 Pages 151-158
    Published: April 25, 1978
    Released: February 19, 2009
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    Tobacco callus was raised from a stem of tobacco mosaic virus (TMV)-infected tobacco plant (cv. Bright Yellow). By means of successive transfers of green colored compact peripheral tissue, intermediate tissue between green and translucent tissue, and translucent soft inner tissue of the callus respectively on Murashige and Skoog's medium, the following 3 types were developed. Callus A; dark green colored callus composed of compactly arranged small cells. Callus B; green colored callus composed of compact peripheral tissue and translucent inner tissue. Callus C; translucent and soft callus composed of loosely arranged large cells.
    TMV concentration in tobacco callus declined by repeated transfers of translucent soft tissue, while it was maintained at a high level when green colored compact tissue was successively transferred. The distribution of TMV in relation to cell arrangement in the tobacco callus was investigated by means of fluorescent antibody technique. TMV antigen in tobacco callus was unevenly distributed, that is, it was frequently localized in compactly arranged small cells around tracheid-like cells, whereas it was rarely observed in soft tissue where large cells were loosely arranged. The decline of TMV concentration in the translucent soft callus was thought to be due to the rapid propagation of healthy cells escaped the virus infection.
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  • Norio NISHIMURA, Kohei TOMIYAMA
    1978 Volume 44 Issue 2 Pages 159-166
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Aged tuber slices of potato cultivars Rishiri (R1-gene) and Irish cobbler (r-gene) were inoculated with race 0 (incompatible with Rishiri and compatible with Irish cobbler) and race 1 (compatible with both cultivars) of Phytophthora infestans. After inoculation, they were treated, at intervals, with 3H-leucine, H332PO4 and 86RbCl solution for 50min, and then washed and homogenized. Uptake of 3H-leucine, and 32P into the 2×104×g supernatant fraction of the homogenates of the slices (Rishiri and Irish cobbler) infected by both races were already lower than those of noninfected ones 1.4hr after inoculation, when most of encysted zoospores had germinated but not yet penetrated the host-cell wall. From about 2.4hr after inoculation, when about 20% of the appressoria had begun to penetrate, the rates of uptake of 3H-leucine and 32P begun to decrease more rapidly in the incompatible host-parasite combination than in those of compatible combinations: At this stage, no death of the infected cells has occurred yet even in the incompatible combination. In the case of 86Rb ion, on the contrary, the rate of uptake was higher in slices infected by the incompatible race than in non-infected slices or slices infected by the compatible race at 18C. At 10C, however there was little difference among the rates of uptake in the non-infected slices and slices infected by incompatible and compatible races.
    The most plausible explanation of these results is that the physiological activity of host-plasmalemma and/or the metabolic activity is altered by infection with the incompatible race in an early period of infection when no host cell death has occurred. From these results it was presumed that the alteration of physiological activity of plasmalemma and/or metabolism of host caused by recognition of infection by an incompatible race of P. infestans might occur almost simultaneously with penetration.
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  • Takeshi OSAKI, Tadao INOUYE
    1978 Volume 44 Issue 2 Pages 167-178
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A whitefly-transmitted virus was purified from tomato leaves affected by tomato yellow dwarf disease. Diseased leaves were extracted with 0.2M borate buffer (pH 8.5), containing 0.1% 2-mercaptoethanol and 1% Antifoam A emulsion. After clarification of the extract with 10% n-butanol, the virus was concentrated by precipitation with 6% polyethylene glycol (PEG) and by sucrose cushion centrifugation. The concentrated virus was partially purified by reverse concentration PEG solubility gradients, then further purified by sucrose density gradients. The ultraviolet absorption spectrum of the purified preparation was typical for nucleoprotein and the A280:A260 ratio was 0.6-0.7. The preparation contained small isometric particles, 15-20nm in diameter, that often occured as pairs, forming a structure of 15-20×25-30nm. The ratio of paired to single particles was approximately 3:1. These particles were disrupted by heavy metal salts used as negative staines, unless they were fixed previously. Very similar particles were also observed in purified preparations obtained from tobacco leaves infected with tobacco leaf curl virus (TLCV). No such particles were found in preparations from healthy control plants.
    Electron microscopy of thin sections of infected tomato, Datura stramonium, and Nicotiana glutinosa leaves revealed the presence of crystalline inclusion showing a rigid rod structure in some of the nuclei in phloem cells. The rods, each of which was approximately 25nm wide, appeared to consist of a large number of geminate particles. Spherical particles of about 16nm in diameter were also found to exist randomly in the nuclei. Similar rods and spherical particles were observed in the leaf cell nuclei of tomato and D. stramonium infected with TLCV. No such structures were found in cells of the mesophyll or the epidermis in diseased plants, nor in cells from healthy plants.
    The results obtained here and from our previous reports indicate that the virus associated with tomato yellow dwarf disease may be identical or closely related to TLCV. It also appears that the geminate particles are the possible causal agent of the two diseases, although infectivity of the purified preparation, containing such particles, is still under investigation.
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  • Koushi NISHIYAMA, Akinori EZUKA
    1978 Volume 44 Issue 2 Pages 179-183
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Eighty species of bacteria belonging to eleven genera, about half of which were plant pathogenic, were tested for their ability to produce coronatine, a new physiologically active substance reported previously to be produced by Pseudomonas coronafaciens var. atropurpurea. Other than this bacterium, only two Pseudomonas species, P. morsprunorum and P. maculicola, were found to produce coronatine.
    Mutants of P. coronafaciens var. atropurpurea lacking the ability of producing coronatine, which were obtained during successive cultures of a virulent wild strain, were not pathogenic on Italian ryegrass, the host plant of the bacterium. Considering the fact that coronatine is a phytotoxic substance, this substance should be indispensable for developing symptoms of halo blight. Coronatine, however, would not be the sole substance governing the mechanism of pathogenicity in P. coronafaciens var. atropurpurea, because P. morsprunorum and P. maculicola were not pathogenic on Italian ryegrass although they produce coronatine.
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  • Toshihiro OMURA, Satoshi WAKIMOTO
    1978 Volume 44 Issue 2 Pages 184-189
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Blocks (5×5×15mm) of tobacco callus tissue different in compactness of cell arrangement were inoculated at the top surfaces with tobacco mosaic virus (TMV) by means of needle pricking. The blocks were then periodically separated into 3 segments and the virus concentration in each segment was assayed by half-leaf method on Nicotiana glutinosa. The infection frequency, multiplication rate and translocation velocity of TMV were higher in compact callus as compared to those in soft callus. TMV translocation in compact callus was estimated over 8mm during 10 days after inoculation, while, less than 3mm during 30 days in soft callus. By means of histological observation under electron microscope, the sieve element, perforated sieve plateand plasmodesmata were frequently observed in compact callus, but none of them in soft callus. The rapid decrease of TMV concentration in the rapidly growing soft callus was attributed partially to the poor infection rate, less multiplication, and slow movement of TMV in soft callus tissue.
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  • Akira SHIRATA, Kokichi TAKAHASHI
    1978 Volume 44 Issue 2 Pages 190-196
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The basal parts 20cm long taken from 1-year-old shoots of cv Ichinose were inoculated with Stigmina mori mycelia after making a wound (1.5×1.5mm) on the bark, then incubated at 2.5 to 30C for various durations. Size of lesions on the inner surface of bark was measured, using the equation; lesion size=√length(mm)×width(mm). The lesion could develop at 2.5 to 15C, with the optimum temperature of 10C. No development of lesion occurred at 20C where fungal growth was the highest on PDA medium. At 10C, lesion size (Y) increased with days after inoculation (X); Y=2.7X-4.3. No further development of lesion was observed even if shoots, which had been kept at 25C for 1 day after inoculation, were transfered to 10C. When shoots were wounded, kept at 5C for 2 days or at 20C for 1 day, then inoculated, majority of shoots failed to develop the lesion. This inhibitory effect was limited to 2-5mm from the wound. Whereas, inhibitory effect on fungal growth in shoots disappeared completely when shoots were stored at -60C for 60min or at 60C for 10min in water bath before inoculation. Shoots having wounds and treated with 2 or 10ppm blasticidin S (BcS) were kept at 20C and, after various intervals, inoculated with mycelia on wounds, then incubated at 10-15C. Lesion developed in BcS-treated shoots, but failed to develop in non-treated ones. When shoots were wounded, incubated at 5 or 20C for 0 to 24hr, treated with 10ppm BcS for 30min, then incubated at 10-15C for 4 days. Effect of BcS on lesion development was observed 12 and 4hr after wounding at 5 and 20C, respectively, indicating that a defence activity of wounded tissues began to appear under these conditions. The defense activity reached maximum about 24 and 8-12hr after wounding at 5 and 20C, respectively.
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  • Masao GOTO, Akihiko TOYOSHIMA, Shunichi TANAKA
    1978 Volume 44 Issue 2 Pages 197-201
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    This paper describes the results of a study on the possibility of the infection of citrus plants due to Xanthomonas citri surviving on the rhizomes of Zoysia macrostachya, root systems of host plants, rice straw mulch or plain soils. Those materials put in the boxes of 40×60×15cm in size were artificially infested by the suspensions of X. citri. The Natsudaidai seedlings at the ten-unfolded leaf age were used as the test plants, and weakly wounded by scratching the leaves with a sand paper prior to the inoculation. Six pots of the individual test plants were placed on the surface of the soil in a box. Inoculation of the test plants was made by splashing with shower produced by a DIK automatic rain simulator which was adjusted for the 50mm precipitation per hour. For this splash inoculation, ten-minute shower was given three times at 8-hour intervals. After inoculation, the test plants were transferred to a greenhouse and observed for the disease development. The leaf infiltration technique was applied for assaying the population of X. citri in the saprophytic forms. As shown in Figs. 1 to 6, the minimum density of X. citri for infection was around 102 per gram samples regardless of the kind of the infested materials. Above this level, the infection ratio increased in parallel with the population of X. citri surviving under the given conditions. The vegetations, either the rhizomes of Z. macrostachya or the root systems of Natsudaidai, substantially increased the infection by the prolonged longevity of the bacterium. The rice straws provided the bacterium with a favorite habitat forming a potential source of infection. The repeated shower over the same boxes with the infested rice straws gave the negligible effects on the population of the bacterium as well as the infection ratio.
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  • Satoshi T. OHKI, Yoji DOI, Kiyoshi YORA
    1978 Volume 44 Issue 2 Pages 202-204
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Atsushi SASAKI, Tsuneo TSUCHIZAKI, Yasuo SAITO
    1978 Volume 44 Issue 2 Pages 205-208
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Setsumi ITOI, Mikio NOZU, Fumio SATO, Jun YAMAMOTO, Chiyoichi NODA, To ...
    1978 Volume 44 Issue 2 Pages 209-213
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In 1977, natural infection of bamboo and bamboo grass (12 species or varieties in 6 genera) by Pyricularia sp. was found in the different localities of Shimane Prefecture in Japan. The fungus on them was morphologically indistinguishable from P. oryzae and P. grisea. Pyricularia isolate from bamboo infected its own host, rice (Aichiasahi and Shin No.2) and other grasses.
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  • Naoyuki MATSUMOTO, Takao ARAKI
    1978 Volume 44 Issue 2 Pages 214-217
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Masako KATAGIRI, Yasuhiko UESUGI
    1978 Volume 44 Issue 2 Pages 218-219
    Published: April 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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