Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 44 , Issue 5
Showing 1-23 articles out of 23 articles from the selected issue
  • Takashi NAIKI, Masakazu KANOH
    1978 Volume 44 Issue 5 Pages 543-553
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In moutainous and cool summer districts in and around Takayama City in Gifu Prefecture, the occurrence of root diseases of spinach (Spinacia oleracea L.) and their pathogens in plastic house cropping were studied during the growing season from May to October, 1977. The pathogenic fungi isolated most frequently from the diseased plants were Fusarium oxysporum f. sp. spinaciae and Rhizoctonia solani, followed by Pythium spp. Aphanomyces sp., Fusarium solani and binucleate Rhizoctonia sp. were additional ones which were isolated less frequently from the diseased plants. The occurrence of the diseased plants was less frequent in May and October, the beginning and the end of cropping season, respectively. Conversely, damping-off of the seedlings in 2-4 leaf-stage caused by R. solani was most serious, followed by Rhizoctonia foot rot and Fusarium wilting of spinach in more than 5 leaf-stage. The differences of the isolation frequency of the pathogenic fungi and the incidence of the diseased plants were found among the fields which varied in their cropping histories and soil textures.
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  • Takashi NAIKI, Masakazu KANOH
    1978 Volume 44 Issue 5 Pages 554-560
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In plastic house cropping of spinach having its growing season from May to October, damping-off and foot rot diseases caused by Rhizoctonia solani Kühn were most serious from June to Septmeber. The occurrence of the fungus was more frequent at the earlier growth stage of the plant. The fungus was more dominant in the plastic house cropping in drained rice paddy fields than in upland fields or in open field cropping, and was less frequent in light clay soil than in clay loam or in loam soil. Isolates of R. solani from spinach were assigned to 5 anastomosis groups (AG). Isolates occurred most frequently and being most pathogenic to spinach seedlings were of AG-4, followed by ones of AG-2, type-2. The former group was most dominant at the earlier growth stage of the plant irrespective of the growing season, cropping histories of the plant and soil types of the fields. The latter group was frequently isolated from drained rice paddy fields and increased with the development of the plant. The groups, AG-1, AG-2, type-1 and AG-1 were additional ones which were found less frequently in plastic house cropping.
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  • Tsutomu UEMATSU, Noriaki NAGAO, Satoshi WAKIMOTO
    1978 Volume 44 Issue 5 Pages 561-569
    Published: December 25, 1978
    Released: February 19, 2009
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    Host-parasite relationships between an isolate of Xanthomonas oryzae, N5874, and two isolates of Bdellovibrio, BdN6801 and BdN6802, were studied by using ultrathin sectioning and electron microscopy.
    With the combination of X. oryzae N5874 and BdN6801, the parasitic process was made clear as follows. Disorganization in the cytoplasm and nuclear area of the host cell was observed from early stage of the attachment of Bdellovibrio. The host components became granular and unevenly distributed, and the host cell changed into spheroplast. A penetration pore was made on the host cell wall at the site of attachment, and the parasite invaded smoothly into the intraperiplasmic space of the host cell. The granulated cytoplasm in spheroplast disappeared gradually to become ghost afterwards with elongation of the parasite. The cytoplasmic membrane of the host, however, remained almost intact till later stage of the latent period. The elongated parasite split into several cells prior to the disruption of host cell wall.
    When BdN6802 attacked X. oryzae N5874, parasitic process was almost the same as in the case of BdN6801 with a few exceptions in some aspects at the site of attachment and penetration. BdN6802 attached to the host cell swelled at anterior tip and the mesosome existing there was often observed. On the occasion of the penetration of BdN6802, the parasite was constricted by X. oryzae cell wall at the marginal part of the penetration pore. The constriction appeared probably due to the rigidity of the host cell wall and insufficient pore size for penetration.
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  • Matsuo SASAKI, Eishiro SHIKATA
    1978 Volume 44 Issue 5 Pages 570-577
    Published: December 25, 1978
    Released: February 19, 2009
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    As the indicator plant of hop stunt disease (HSD) agent, cucumber plants were used to investigate the properties of HSD agent. HSD agent in crude sap from diseased cucumber plants was not inactivated after heating at 84C for 10min, lost its infectivity when diluted 1/10, 000, and kept for one day at 20C, but not after three days at 4C. HSD agent was easily extractable with buffers of high ionic strength (0.5M K2HPO4). The agent remained in the supernatant of high speed centrifugation (113, 000×g, 2 hours), was extracted with phenol and precipitated with ethanol. The agent was inactivated with RNase, but not with DNase. Fraction showing high infectivity was detected between 6S and 9S by the 5-20% sucrose density gradient centrifugation. The results indicate that HSD agent is a low molecular weight ribonucleic acid, a viroid.
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  • Mitsuro IWAKI, Akinobu NAKANO, Hiromi IEMURA, Hiroshi TOCHIHARA
    1978 Volume 44 Issue 5 Pages 578-584
    Published: December 25, 1978
    Released: February 19, 2009
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    “Kohan” disease of lettuce, resembling lettuce big vein disease and hitherto unknown to Japan, has occurred in Wakayama Prefecture. The main symptom on lettuce was a chlorosis along the leaf vein, and a characteristic boundary line between chlorotic and green areas. The causal agent was not transmitted by mechanical inoculation from a diseased leaf of lettuce to several test plants, by aphid, Myzus persicae, from diseased lettuce to healthy lettuce, and also, through seed of lettuce. Virus-like particles were not detected from diseased leaf tissues of lettuce in electron microscopic studies using direct negative staining technique and ultrathin section method. When healthy lettuce seedlings were transplanted into the soil collected from beneath the infected plants from several farms, they showed typical symptoms at high percentage 20-45 days later. The infested soil remained infectious after air-drying for 3 weeks. Lettuce seedlings that had been transplanted to soil containing the roots of naturally infected plants developed symptoms, whereas those that were transplanted to soil containing the leaves of naturally infected plants, did not. Resting spores and zoosporangia of Olpidium sp. were found in roots of all naturally infected plants. The causal agent was transmitted to lettuce by zoospores collected from roots of naturally infected plants. And also, it was transmitted by grafting scions from diseased plants to the stem of healthy plants, but not through soil containing the roots of diseased plants that had been infected by grafting.
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  • Makoto KOJIMA, Tyng-guang CHOU, Eishiro SHIKATA
    1978 Volume 44 Issue 5 Pages 585-590
    Published: December 25, 1978
    Released: February 19, 2009
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    Immune electron microscopic (IEM) methods were successfully applied to a rapid diagnosis of potato leaf roll virus (PLRV). PLRV particles were easily detected as specific virus clumping when the clarified, unconcentrated preparations obtained from diseased young potato sprouts and the PLRV antiserum were mixed and incubated overnight in a cold room (clumping method). In addition, support films covered with PLRV antiserum in advance efficiently trapped PLRV particles (modified Derrick method). Futhermore, the individual particles were accurately detectable by the increase of their size with due to a specific halo, when the procedure (modified Derrick method) was followed by decoration with either antiserum or the purified IgG (immunoglobulin G) component. As the diagnosis of PLRV can be made within a few days, this method will be applicable to routine indexing for PLRV for inspection programs.
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  • Shiro KUNINAGA, Ryozo YOKOSAWA, Akira OGOSHI
    1978 Volume 44 Issue 5 Pages 591-598
    Published: December 25, 1978
    Released: February 19, 2009
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    Hyphal anastomosis grouping of Rhizoctonia solani isolated from non-cultivated soils in Hokkaido was attempted. From 208 soil samples of non-cultivated areas, 363 isolates were collected. Of these, 84 isolates belonged to anastomosis groups, AG-1, AG-2-1, AG-2-2, or AG-5. AG-3 and AG-4 were not detected. For classification of the remaining 279 isolates, new anastomosis groups, AG-6 and AG-BI, were established. The rates of isolation frequency of AG-1, AG-2-1, AG-2-2, AG-5, AG-6 and AG-BI were 3.0%, 1.9% 9.7%, 8.5%, 71.1% and 5.8% respectively. AG-6 was the most predominant group of R. solani in non-cultivated soils in Hokkaido.
    There were similarities among the culture types of AG-1 from non-cultivated and cultivated soils, and were also the same as AG-5. Those of AG-2-1 and AG-2-2 from non-cultivated soils were different from those from cultivated soils. Cultural appearance of AG-6 was yellowish-brown or dark-brown in colour, and the tissues of sclerotium were loose. Culture types of AG-BI were variable and some of them resembled those of AG-2-1, AG-2-2, or AG-3 from cultivated soils. AG-1, AG-2-1, AG-2-2 and AG-5 from non-cultivated soils ranged from weakly virulent to highly virulent isolates. AG-6 and AG-BI were nearly avirulent.
    Judging from the anastomosis behaviour and cultural appearance of AG-BI, close relations among five anastomosis groups, AG-2-1, AG-2-2, AG-3, AG-6 and AG-BI, were suggested.
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  • Norio NISHIMURA, Kohei TOMIYAMA, Noriyuki DOKE
    1978 Volume 44 Issue 5 Pages 599-605
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Both sides of aged disks of potato tuber (Rishiri, R1-gene) were inoculated by incompatible race 0 or compatible race 1 of Phytophthora infestans. Five min pulse label experiments with L-leucine-4, 5-3H of the infected disks showed that uptake of radioactivity from 3H-leucine into the disks was greatly reduced by infection with the incompatible race as previously reported, but the ratio of incorporated radioactivity in acid insoluble fraction of the disks to total radioactivity in the 20, 000×g supernatant was increased with infection by the incompatible race 0. In the case of compatible race 1, the infection had less effect on the incorporation ratio of the radioactivity into acid insoluble fraction than with the incompatible race 0. These results suggested that reduction in 3H-leucine uptake may be due to alteration of physiological activity of host plasma membrane, but not to reduction of metabolic activity. Treatment of tuber disks with insoluble fraction of the zoosporial homogenate of race 0 or race 1 greatly reduced the uptake of 3H-leucine by the disks. The supernatant fraction of the zoosporial homogenates also reduced the uptake, but the effect was lost by dialysis.
    Little difference was observed in the effect of insoluble and soluble fractions of the zoosporial homogenates of both race 0 and race 1. The insoluble fraction of the zoosporial homogenates of both race 0 and race 1 had little effect on the ratio of the radioactivity in acid insoluble fraction of the tuber disks to total uptake of the radioacitivy in 20, 000×g supernatant. These results suggest that some substances in insoluble components of zoosporial homogenate of P. infestans may be at least one cause of the reduction in uptake of 3H-leucine which begins to occur in a very early period of inoculation with race 0 or race 1 while penetration hasn't yet occurred.
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  • Keizo KATSUYA, Makoto KAKISHIMA, Shoji SATO
    1978 Volume 44 Issue 5 Pages 606-611
    Published: December 25, 1978
    Released: February 19, 2009
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    Urediniospores of Puccinia coronata f. sp. avenae race 367 and P. recondite f. sp. tritici race 45 were respectively cultured on an artificial medium. Urediniospores free of contaminating microorganisms were obtained by aseptic leaf culture. After the urediniospores were separately seeded on the medium, both rust fungi grew well and then formed white macroscopic colonies which had abundant aerial hyphae. About 1.5-2 months after inoculation part of the colonies changed from white to dark brown. Microscopic examination showed that spore-like bodies similar in morphology to urediniospores and teliospores were formed around the stroma. In the culture of P. coronata f. sp. avenae, teliospore-like bodies did not show a crown on top of the spores.
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  • Kazuo ABIKO
    1978 Volume 44 Issue 5 Pages 612-618
    Published: December 25, 1978
    Released: February 19, 2009
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    The inoculation experiments and morphological observations were made to clarify the physiological specialization of Sphaerotheca fuliginea parasitic on Cucurbitaceous plants, eggplant, edible burdock and Japanese butterbur. The inoculation experiments of the fungi parasitic on melon, cucumber, winter squash and bottle gourd onto nineteen host plants of S. fuliginea showed that these isolates were similar in their host ranges. Mamely, melon, cucumber, winter squash and bottle gourd became infected easily by the fungi, but watermelon and white gourd belonging to the same family, Cucurbitaceae, were not infected. Helianthus annuus, Cosmos bipinnatus, Zinnia elegans of the Compositae and Impatiens balsamina of the Balsaminaceae were also infected by these isolates. The fungus on watermelon had nearly similar host ranges to that parasitic on melon. Water melon fungus, however, was more virulent on watermelon than melon fungus. Fungi which were parasitic on eggplant, edible burdock and Japanese butterbur were virulent only on their respective original host plants. Morphological observations showed that the length of the conidia of the fungus parasitic on eggplant was somewhat longer than that of the fungus parasitic on melon, and that any other remarkable difference was not found among the fungi parasitic on other plants. Five specialized forms of S. fuliginea were recognized according to their host ranges. They are: (1) Fungus parasitic on Cucurbitaceae, except watermelon and white gourd; (2) fungus parasitic on watermelon; (3) fungus parasitic on eggplant; (4) fungus parasitic on edible burdock and (5) fungus parasitic on Japanese butterbur. Each of the above-mentioned fungi can be regarded as a specialized form of S. fuliginea.
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  • Kenichiro SHOHARA, Tadao INOUYE
    1978 Volume 44 Issue 5 Pages 619-625
    Published: December 25, 1978
    Released: February 19, 2009
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    Simplified radial and double diffusion (SRD and SDD, respectively) techniques were developed for rapid detection and serodiagnosis of cucumber mosaic virus (CMV). Both techniques were based on immunodiffusion test in agar gel on microscopic glass slide with some modification. Filter paper disks were arranged on agar bed (containing antiserum for SRD test) as antigen reservoirs, on which NaCl treated leaf tissues were mounted. For SDD test, filter paper saturated with antiserum was placed on agar gel, and filter paper disks for sample antigens were arranged around it. Solution of 24% NaCl was used successfully for dissociating CMV (including 5 isolates) into fast diffusible and immunoreactive antigen. Immunoreactions were finally read after overnight period at room temperature. The serological detection of CMV was found to be as sensitive as, or in some cases, more reliable than bioassay on cowpea. Nonspecific precipitates sometimes occurred in agar gel with plant species excepting main vegetables. The precipitates, however, did not seriously interfere with interpretation of SDD test.
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  • Hiroshi YAEGASHI
    1978 Volume 44 Issue 5 Pages 626-632
    Published: December 25, 1978
    Released: February 19, 2009
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    Heterothallic isolates of Pyricularia pathogenic on different hosts were used to demonstrate experimentally the genetic segregation of factors for pathogenicity and mating type through the perfect stage. The pathogenicity of 325 monoascosporic progeny from the crosses of Pyricularia isolates from weeping lovegrass and finger millet to the original hosts segregated 136:127:26:36; pathogenic to weeping lovegrass alone, finger millet alone, both weeping lovegrass and finger millet, and nonpathogenic to both hosts, respectively. Based upon a 1:1 segregation, the pathogenicity to weeping lovegrass or finger millet seems to be conditioned by a single gene. The results suggest that factors for pathogenicity to two hosts are conditioned by different genes located at different loci on homologous chromosomes. Mating type was inherited independently of pathogenicity. Pathogenicity and mating type were determined for eight ascospores from a single ascus. Judging from the ascospore analysis and the previous cytological study of the ascus, it seems that factors for pathogenicity and mating type are conditioned by chromosomal genes.
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  • Tsuneo WATANABE, Koji HASHIMOTO
    1978 Volume 44 Issue 5 Pages 633-640
    Published: December 25, 1978
    Released: February 19, 2009
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    Gloeocercospora sorghi was recovered from 68% of sorghum seeds collected from the severely-diseased field at Ebina (Kanagawa prefecture), the emergence rate of these seeds grown in autoclaved soil was as low as 20%, and 80% of the emerged seedlings were diseased with lesions on their leaves. The fungus was recovered from stems near the ground from 2 out of 39 young seedlings originated from pathogen-free seeds and grown in the diseased soil collected from Ebina, but no fungus was recovered from seedlings grown in autoclaved soil. The conidia, which were variable in size and number of septation in media tested, germinated 100% within 4hr on water agar (WA) plates at 20-30C. Sclerotia prepared from 30-day-old culture also germinated 96%, and 22% of them formed sporodochia directly on them on WA in 4 days after seeding. The fungus might penetrate within 2hr and symptoms developed within 24hr after inoculation. Results indicate that the fungus is transmitted through infected seed, and also survives in soil with a potentiality causing infection.
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  • Tomonori SHIRAISHI, Hachiro OKU, Yoshio TSUJI, Seiji OUCHI
    1978 Volume 44 Issue 5 Pages 641-645
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pycnospores of Mycosphaerella pinodes, a non-obligate parasite of pea plant did not induce pisatin accumulation until they established infection, probably suppressing defense reaction of the host. This fungus was highly tolerant to pisatin as assessed by the inhibitory activity to spore germination or germ-tube elongation (ED50=500ppm). The fungus, however, could not establish infection on pea if a very low concentration (less than 50ppm) of pisatin was administered artificially into the spore inoculum. The perforation of cellophane-sheet by germ-tube of M. pinodes was also inhibited by the same concentration of pisatin that inhibited infection on the host. These results suggest strongly that the importance of phytoalexin as an anti-infectional factor in defense reaction of host rather than antifungal substance and pea pathogen, M. pinodes suppresses pisatin production in early stage of infection in order to avoid its inhibitory effect on infection.
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  • Masao GOTO
    1978 Volume 44 Issue 5 Pages 646-651
    Published: December 25, 1978
    Released: February 19, 2009
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    Rice cultivers from different Asian countries were tested for their responses to the bacterial foot rot disease. Inoculation by spraying bacterial suspension was not useful for the test. The injection method proved more useful. With high inoculum doses, a majority of the cultivars tested suffered severe infection and the symptoms produced were very similar. As the dose was decreased, varying degrees of resistance became detectable depending on the cultivars. In the inoculum density of 1×104 cfu per tiller, a few varieties showed a high resistance. In 2×103 cfu per tiller, varietal differences in resistance became more distinct. Taichung 65 which was severely attacked in the field showed a high level of susceptibility resulting in decay of stems at the base. Some other varieties, however, were slightly infected at this level of inoculum or completely free from the disease. When the dose was further decreased to 2×10 cfu, many varieties became tolerant to the disease development though some showed a moderate infection.
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  • Nobuaki MATSUYAMA, Zenichi MOROMIZATO, Akira OGOSHI, Satoshi WAKIMOTO
    1978 Volume 44 Issue 5 Pages 652-658
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A collection of 48 isolates selected from various anastomosis groups of Rhizoctonia solani showed at least nine distinct zymograms. Isolates from rice (sasakii type), or its relatives showed zymogram Zym-1. However, other isolates in the same anastomosis group (AG-1), from other host plants (web-blight type) showed several other different zymograms. Isolates from mat rush (Igusa), rice (quasi-sheath blight) and sugar beet in AG-2-2 gave Zym-2-2A which resembled Zym-1. Other members of AG-2-2 from sugar beet gave a different zymogram Zym-2-2B. Isolates of AG-2-1 gave the pattern Zym-2-1 which was quite different from all others. Isolates from potato (AG-3), showed a characteristic zymogram Zym-3. Similar zymograms were given by some isolates of anastomosis group AG-5 which also came from potato. The zymograms roughly agreed with anastomosis groups, but sometimes were more closely correlated with ecological types. The significance of these results and their usefulness are discussed.
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  • Tomonori SHIRAISHI, Hachiro OKU, Masao YAMASHITA, Seiji OUCHI
    1978 Volume 44 Issue 5 Pages 659-665
    Published: December 25, 1978
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Both elicitor and suppressor of pisatin accumulation in pea leaves were found in the pycnospore germination fluid of Mycosphaerella pinodes, a pathogenic fungus of pea plant. The elicitor was a high, whereas the suppressor was a low molecular weight substance. The suppressor counteracted the activity of elicitor. Purification of suppressor from low molecular weight fraction by gel filtration and TLC gave two active components, F2 and F5. These substances were found to be low molecular weight peptides because they showed positive color reaction with ninhydrin and Lowry reagents. Both F2 and F5 inhibited pisatin accumulation in pea leaves induced by inoculation with non-pathogens, Erysiphe graminis hordei and Stemphylium sarcinaeforme. The activity of F5 was stronger than F2. F5 inhibited completely the accumulation of pisatin at a concentration of 50μg/ml, and rendered pea leaves accessible to S. sarcinaeforme.
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  • Yasuo SAITO, Hitoshi INOUE, Hirowo SATOMI
    1978 Volume 44 Issue 5 Pages 666-669
    Published: December 25, 1978
    Released: February 19, 2009
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    A disease of rice plants similar to tungro disease in symtoms occurred in Okinawa, Japan, in 1977. A virus belonging to rhabdovirus group was observed in both ultratnin sections and dip preparations from diseased plants. The virus was transmitted in a persistent manner by the green rice leafhopper, and was identified as rice transitory yellowing virus.
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  • Yoshio KUROSAKI
    1978 Volume 44 Issue 5 Pages 670-673
    Published: December 25, 1978
    Released: February 19, 2009
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    To investigate the water permeability of the brown-discolored marginal zone, artificial lesions were prepared by means of inoculation at heat-injured spots. These lesions formed sharp brown-discolored zone which seemed to barricade the parasite. Water content of these lesions decreased rapidly even under sufficient water supply, suggesting that the brown-discolored tissue inhibits the supply of water and water soluble nutrients to the fungus enclosed in the lesion.
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  • 1978 Volume 44 Issue 5 Pages 676a
    Published: 1978
    Released: February 19, 2009
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  • 1978 Volume 44 Issue 5 Pages 676b
    Published: 1978
    Released: February 19, 2009
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  • 1978 Volume 44 Issue 5 Pages 676c
    Published: 1978
    Released: February 19, 2009
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  • 1978 Volume 44 Issue 5 Pages 676d
    Published: 1978
    Released: February 19, 2009
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