Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 65 , Issue 2
Showing 1-19 articles out of 19 articles from the selected issue
  • Seiji TSUGE, Yumi IKAWA, Yasufumi HIKICHI, Yoshiko NAKAZAWA-NASU, Kazu ...
    1999 Volume 65 Issue 2 Pages 93-99
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Transposon Tn4431 was used to introduce a luciferase (lux) operon into Xanthomonas oryzae pv. oryzae (X. o. pv. oryzae) T7174. Two transconjugants which were highly bioluminescent and indistinguishable in pathogenicity with the parental strain were selected. The transconjugants produced more bioluminescence in the logarithmic phase in liquid cultures. Bioluminescence was also detected from rice leaves infected with the transconjugants. In the compatible rice cultivar IR24 bacteria multiplied and moved prior to the expression of disease symptoms. In contrast, in the incompatible rice cultivar IR-BB2, which has resistance genes Xa1 and Xa2, bioluminescence was restricted near the inoculation sites, but light produced by the transconjugants was detected even 3 weeks after inoculation, suggesting that bacteria could multiply, although restrictedly, and remain viable. No bacterium was reisolated from the leaf sections beyond the light-producing regions. The detection of bioluminescence makes it possible to examine the actual location or infection process of X. o. pv. oryzae continuously without destroying the infected leaves.
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  • Yasuhiro INOUE, Yuichi TAKIKAWA
    1999 Volume 65 Issue 2 Pages 100-109
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Some repeating sequences were identified from Pseudomonas syringae strains in the neighboring region of their hrp genes cluster. This sequence was located at the left side of the hrpL region, lacking a terminal inverted repeat at one end. P. s. pv. actinidiae also had two repeating sequences at the left side of the hrpL region. One of them is similar to IS1240. Southern blot analysis revealed homologous fragments among many strains of P. syringae and patterns of hybridization signal strength. The number of bands varied among them. P. s. pv. phaseolicola has been reported to have the avrPphE gene on the left side of the hrpL gene. Sequence analysis of AvrPphE- strain NPS3121 showed insertion of a 104-bp DNA fragment in avrPphE, which is homologous to the terminal inverted repeat and the target sequence of the IS5 family. These results suggested that genetic modifications have accumulated in the left outside region of the hrpL gene in many strains of P. syringae.
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  • Hiroyuki KANAMORI, Hitoshi SUGIMOTO, Hirokazu OCHIAI, Hisatoshi KAKU, ...
    1999 Volume 65 Issue 2 Pages 110-115
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Two cosmid clones (pXCF13-38 and pXCF13-44) were isolated from a genomic library of Xanthomonas campestris pv. citri strain L-9 using pVir2, a cosmid clone of the hrp cluster of Ralstonia solanacearum, as the probe. 25kb region consisting on these clones was identified as the hrp region from a test of pathogenicity on citrus and of the hypersensitive response on tobacco after marker exchange of Tn3-Spice insertions. As pXCF13-38 covered almost the entire hrp cluster, this clone was used as the probe for RFLP analyses of xanthomonads. A dendrogram was drawn based on analyses of RFLP patterns and was distinguishable from reported dendrograms based on biochemical characters and on RFLP analyses using randomly chosen probes. From these results, the usefulness of RFLP analysis of hrp clusters for identification of various xanthmonads was shown and independent evolution of hrp cluster in xanthomonads was suggested.
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  • Yoshihiro NARUSAKA, Mari NARUSAKA, Takeshi HORIO, Hideo ISHII
    1999 Volume 65 Issue 2 Pages 116-122
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Systemic acquired resistance (SAR) is an inducible defense mechanism that plays a central role in plant disease resistance and can be induced by different compounds. In this study, acibenzolar-S-methyl (benzo [1, 2, 3] thiadiazole-7-carbothioic acid S-methyl ester) was shown to induce acquired resistance in cucumber. The signal(s), which induced resistance against scab (pathogen: Cladosporium cucumerinum), was systemically transferred as early as 4 to 6hr after treatment with acibenzolar-S-methyl. Expression of resistance-related genes, i.e., genes of acidic peroxidase, acidic class III chitinase and acidic β-1, 3-glucanase, was also induced by the treatment. Although systemic expression of peroxidase and chitinase genes was induced not only in the first leaves treated with acibenzolar-S-methyl but also in the untreated upper leaves, the induction of β-1, 3-glucanase gene was not systemically enhanced in cucumber plants within 24hr of the treatment. Since resistance against C. cucumerinum was already induced by 24hr after acibenzolar-S-methyl treatment, β-1, 3-glucanase might not participate in the protection against attack by the pathogen at an early stage in the SAR induced by this compound. Thus, acibenzolar-S-methyl seems to activate the SAR signal transduction pathway in cucumber plants. Subsequently, this compound rapidly induces the expression of SAR genes and disease resistance in the plants.
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  • Permpong SRIPRASERTSAK, Andi SALAMAH, Yoshiyuki IMURA, Yuki ICHINOSE, ...
    1999 Volume 65 Issue 2 Pages 123-130
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The 5'-upstream region of the pea phenylalanine ammonia-lyase gene2 (PSPAL2-FL, -2196 to +110) promoter was dissected by deleting in a series and fused to the coding region of the reporter gene encoding β-glucuronidase (GUS). The constructed chimeric promoters designated as PSPAL2-FLd1 (-1486 to +110), PSPAL2-FLd2 (-966 to +110), PSPAL2-FLd3 (-594 to +110) and the full-length promoter PSPAL2-FL (-2196 to +110) were used to transform tobacco plants by the Agrobacterium-mediated leaf disk method. Histochemically, GUS expression of the PSPAL2 promoter was examined in mature leaves of these transgenic tobacco leaves inoculated with pathogenic and non pathogenic fungi. GUS expression was induced by inoculation with a non pathogen, Phytophthora capsici, as detected by a very clear expression zone around the hypersensitive response (HR) area, especially in the transformants of PSPAL2-FL and PSPAL2-FLd1. However, on leaves inoculated with a pathogen, P. nicotianae, only weak and hazy colorations were detected around the inoculation site even in the transformant of PSPAL2-FL. Moreover, wounding mature leaves with a sterile razor blade also triggered remarkable expression around the wounded sites, especially in the transformant of PSPAL2-FL. We suggest that PSPAL2 promoter expression in transgenic tobacco is induced not only by fungal ingression but also by wounding.
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  • Shunji SUZUKI, Yukiko KOMIYA, Tomohiro MITSUI, Shinji TSUYUMU, Hitoshi ...
    1999 Volume 65 Issue 2 Pages 131-139
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The production of pectinases and the expression of genes encoding pectinases by conidia and germlings of Blumeria graminis f. sp. tritici were investigated. By pectate plate assay, the activity of polygalacturonase was detected in homogenates from ungerminated conidia and germlings grown on an artificial substratum. We could amplify the fragments of two endo-polygalacturonase genes, two pectin lyase genes and a pectate lyase gene from genomic DNA of the fungus by the polymerase chain reaction (PCR). The genes were designated as pg1 and pg2, pnl1 and pnl2, and pel1, respectively. Their nucleotide sequences and the deduced amino acid sequences of their fragments showed high homology to those of the reported sequences of corresponding pectinases of other fungi. The RT-PCR indicated the expression of pg1, pg2 and pnl2 in ungerminated conidia and germlings. The expression of pnl1 and pel1 was detected only at the late stage of the infection in wheat leaves but not in ungerminated conidia and germlings on an artificial substratum and at an early stage of infection in wheat leaves. The present results suggested possible involvement of pg1, pg2, pnl1, pnl2 and pel1 in morphogenesis and/or pathogenesis of this fungus.
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  • Ting-Hsuan HUNG, Meng-Ling WU, Hong-Ji SU
    1999 Volume 65 Issue 2 Pages 140-146
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The greening fastidious bacteria (GFB), also tentatively named Liberobacter, cause citrus greening disease. They unevenly inhabit the sieve tubes of host plants in low concentration. A highly sensitive and specific DNA probe, developed with DNA cloning methods has been used to detect GFB in infected citrus hosts. One of the clones containing a 0.24-kb GFB-specific DNA fragment was labeled with biotinylated nucleotides by a PCR-labeling technique. A dot hybridization assay with the biotin-labeled DNA probe has been successfully used for detecting GFB in various citrus hosts including mandarins, tangors, sweet oranges and pummelos. This probe could specifically react with all GFB strains from several Asian countries, but not with those from South Africa. The probe developed has specificity and sensitivity sufficient enough to detect minute levels of GFB infection and, therefore, can be used in quarantine of the Asian greening disease.
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  • Hideki NAKADA, Aiko TAHARA, Masaharu HAYASHI, Rena SHIMIZU, Rui TANAKA ...
    1999 Volume 65 Issue 2 Pages 147-152
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The hrp gene locus of Pseudomonas syringae pv. pisi (P. s. pisi) race 1 was cloned in SuperCosl vector. The nucleotide sequences of hrpA, hrpB and hrpZ were determined, and the deduced amino acid sequences were compared with different races of P. s. pisi and corresponding genes in other bacteria. In particular, over 99% of the similarity in HrpZ (harpin) amino acid sequences was observed among the different races of P. s. pisi. Among P. syringae pathovars, very high similarity was observed, but the level of similarity was considerably lower than that of Erwinia. The HrpZ protein is rich in glycine but lacks cysteine. It is also heat tolerant as has been reported with other bacterial harpins. The carboxyl terminus of harpin also contains two directly repeated sequences of GGGLGTP and QTGT commonly found in P. syringae pv. syringae. It is very interesting to note that a tetrapeptide sequence, GDET, homologous to the hexapeptide Mycosphaerella pinodes-supprescin B (SSGDET) was found in HrpZ of P. s. pisi.
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  • Naohiro HONDA, Mitsuyo HIRAI, Takashi ANO, Makoto SHODA
    1999 Volume 65 Issue 2 Pages 153-162
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Alcaligenes faecalis No.4 (No.4), which showed a significant suppressive effect on the growth of 13 kinds of plant pathogens in vitro, produced hydroxylamine, nitrite and nitrate in liquid cultivation. This indicates that No.4 is a heterotrophic nitrifier. As hydroxylamine solution formed a clear growth inhibitory zone on a plate inoculated with Rhizoctonia solani K-1 in vitro, the aforementioned suppressive effect was considered to be due to the hydroxylamine produced by No.4 during heterotrophic nitrification. When culture broth, cell suspension and supernatant of No.4 were applied to sterilized soil containing R. solani, the damping-off of tomato seedlings caused by R. solani was suppressed significantly. However, in non-sterilized soil, damping-off was suppressed only by the culture broth and the cell suspension treatments, presumably because hydroxylamine in the supernatant was decomposed in soil. Transposon mutagenesis was applied to No.4 to produce a non-hydroxylamine-producing mutant, No.4-1, which showed no suppressive effect on the growth of R. solani either in vitro or in vivo. These data indicate that the hydroxylamine produced by No.4 is involved in the suppression of damping-off caused by R. solani.
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  • Ryo NISHIMURA, Kaori SATO, Wang Hyu LEE, U.P. SINGH, Tun-tschu CHANG, ...
    1999 Volume 65 Issue 2 Pages 163-170
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The mating type, allozyme genotypes of malic enzyme, glucose-6-phosphate isomerase and peptidase loci, and metalaxyl sensitivity of 336 Phytophthora infestans isolates collected in Korea, India, Taiwan, Indonesia, Thailand, Nepal, and China between 1992 and 1997 were determined. Only A1 mating type isolates were detected in India and Taiwan, and only A2 isolates in Korea and Indonesia, while both mating type isolates were detected in Thailand, Nepal, and China. The isolates from Korea, India, Taiwan, and Indonesia had a single allozyme genotype respectively, while the isolates from Thailand, Nepal, and China had two or three allozyme genotypes. Isolates that were highly resistant to metalaxyl were found in Korea, Indonesia, and China. All of the isolates from Taiwan and India, and some of the isolates from Thailand, Nepal, and northern and southern areas of China, belonged to the old population of P. infestans, which was predominant worldwide until the appearance of A2 isolates outside central Mexico. Some of the isolates from Thailand and Nepal were from new populations that have been discovered since the appearance of A2 isolates outside central Mexico. All of the isolates from Korea and Indonesia and most of the isolates from China belonged to two specific populations, which have been rarely detected elsewhere. The occurrence of these separate populations in Asia suggests that they followed a different migration pathway, or that they are better adapted to Asian conditions than to those elsewhere in the world.
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  • Ampaabeng Gyedu KYEREMEH, Toshio KIKUMOTO, Duen-yau CHUANG, Yuichi GUN ...
    1999 Volume 65 Issue 2 Pages 171-176
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A modified Bacto potato-dextrose agar (PDA) was prepared by incorporating bromothymolblue (BTB), crystal violet and lactose into PDA. This medium was used as a selective and diagnostic medium for isolating copper- and bactericide-resistant mutants of putative biocontrol agents of the soft-rot bacterium, Erwinia carotovora subsp. carotovora. Putative mutants resistant to between 3.75-6.26mM (600-1000μg/ml) copper sulfate were isolated through three sequential isolations on this medium. The copper resistance of this bacterium increased gradually following each isolation. However, these mutants were found to be susceptible to copper-based bactericides like copper (II) hydroxide, dithianon-copper chloride basic and organic copper. Moreover, a decrease in the copper resistance of the mutants, especially those of strain 2T-2 was observed after a period of storage but no change in their bacteriocin activity was observed. Using these mutants as parents, spontaneous mutants resistant to 250- and 500-times dilution of organic copper and copper sulfate basic on PDA, respectively, were isolated. One of these mutants designated as 2TQ-rif-4 survived in 600- and 1200-times diluted solutions of organic copper for at least 3 and 6hr, respectively. As much as 106cfu/ml of this mutant survived in the solution of organic copper for 24hr at a dilution rate of 1800-times.
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  • Masao ARAKAWA, Hitoshi KUNOH
    1999 Volume 65 Issue 2 Pages 177-183
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    It was examined whether successful infection by Blumeria (syn. Erysiphe) graminis f. sp. hordei (a pathogen) induced production of some chemical factors which could explain the accessible state of coleoptile cells of barley. Water-soluble extracts were prepared from coleoptiles 0, 6, 12, 18hr after inoculation with B. graminis and uninoculated coleoptiles. Coleoptiles whose lower surfaces were treated with these extracts, were inoculated with Erysiphe pisi (a nonpathogen), and its penetration efficiency (PE) was examined. This nonpathogenic fungus formed haustoria at a significantly high PE level only in the coleoptiles treated with extracts of the B. graminis-inoculated coleoptiles prepared at 18hr after inoculation but not with those extracted earlier than 12hr. These results suggested that some chemical factors might be produced in coleoptiles by 18hr after inoculation of B. graminis, at the time of incipient development of its haustoria. In thin layer chromatography of the extracts, a bluish fluorescence under UV light and a ninhydrin-positive spot was detected at position Rf=0.61. The fraction containing this spot and two other fractions which were not detected by UV or the ninhydrin reaction had accessibility-inducing activity, suggesting that some of these factors may associate mutually to induce accessibility in coleoptile cells.
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  • Rena SHIMIZU, Korehiro AKAISHI, Hideaki NEGISHI, Hiroshi TANAKA, Yuki ...
    1999 Volume 65 Issue 2 Pages 184-188
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Shigeharu TAKEUCHI, Yasufumi HIKICHI, Yoichi KAWADA, Tetsuro OKUNO
    1999 Volume 65 Issue 2 Pages 189-191
    Published: April 25, 1999
    Released: February 19, 2009
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  • Ahmad YUNUS, Shinji KAWAMATA, Tadayuki SHIMANUKI, Yasuhiro MURAKAMI, Y ...
    1999 Volume 65 Issue 2 Pages 192-196
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Nobuya TASHIRO, Kiyotaka MIYASHITA, Yoshimitsu MATSUO
    1999 Volume 65 Issue 2 Pages 197-203
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The existence of the causal agent of potato scab in high acid soils having a pH as low as 4.4 was confirmed in Japan. A five years survey of potato fields in the Uwaba area in Saga Prefecture revealed the occurrence of potato scab disease in high acid soils with pH values of less than 5.2. A pathogenic Streptomyces sp. forming rectiflexibile spore chains (RF type) was isolated in high density from scab lesions of potato tubers grown in high acid soil. On the other hand, a pathogenic Streptomyces sp. forming spiral spore chains (S type) was isolated in low density from the same tubers. The S type pathogens could not grow on acidic media with pH values of less than 4.5, however, that of the RF type could grow on acidic media with a pH value of 4.0. The optimum pH values for ATP production of S type and RF type pathogens were 6.0 and 5.0, respectively. Severe pathogenicity of RF type pathogen was observed in soil with a pH value of 4.4 in the field inoculation test.
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  • Kazuo ABIKO, Hiroshi HAGIWARA
    1999 Volume 65 Issue 2 Pages 204-206
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In the autumn of 1997, a powdery mildew of Jew's marrow was found in Mie prefecture, Japan. White, powdery mycelia appeared on leaves, pods and shoots. Conidia with fibrosin bodies were ellipsoid to elongate-ellipsoid, 31.2-41.6×16.5-20.8μm and formed in chains. Conidiophores were erect on superficial mycelium, 67-125μm in length. Germ tubes from conidia were simple, not branched. No cleistothecium was observed. Based on the conidial stage, the fungus was identified as Oidium sp. of the Sphaerotheca fuliginea type.
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  • Shin-ichi FUJI, Hitoshi NAKAMAE
    1999 Volume 65 Issue 2 Pages 207-210
    Published: April 25, 1999
    Released: February 19, 2009
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    Japanese yam mosaic virus was detected using ELISA and RT-PCR assays. In ELISA, Japanese (Dioscorea japonica) and Chinese yams (D. opposita) infected with JYMV reacted positively, but white yam (D. alata) infected with JYMV, Chinese yam infected with CYNMV and virus-free yam did not react. ELISA values differed among JYMV isolates. In RT-PCR, the PCR product was detected from all yams infected with JYMV, but not from yam infected with CYNMV and virus-free yam. These results suggest serological diversity among JYMV isolates.
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  • Nobuya TASHIRO
    1999 Volume 65 Issue 2 Pages 211-215
    Published: April 25, 1999
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Using etiolated potato sproutings, the pathogenicity of potato scab-causing Streptomyces spp. was simply assessed. The cut sproutings (6-8cm long) were wrapped individually with a piece of tissue paper containing a concentrated spore suspension of the isolates with different pathogenicity. After keeping for 7 days at 25°C and high humidity under dark conditions, the sproutings were examined for necrotic and raised lesion formations. The pathogenicity of the isolates examined by this simple method was completely coincided with that assessed by the conventional soil inoculation method.
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