Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 62 , Issue 2
Showing 1-23 articles out of 23 articles from the selected issue
  • Shigehisa KIYOSAWA, Donna PURBA, Md. Shamsher ALI, Yasushi OKINAKA, Ts ...
    1996 Volume 62 Issue 2 Pages 95-100
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Using the simulation model for a four gene system on host-pathogen relationship, we studied the principles included in determination of types (cross- and noncross-types) of nonrandom associations between avirulence loci in a pathogen population. Analyses were carried out by giving some changes in host genotype frequencies which bring equilibrium conditions in frequencies of pathogen genotypes. Determination of types [cross-type (C) and noncross-type (N)] of nonrandom association was conducted by complicated but definite principles. When four avirulence genes (a, b, c and d) and four corresponding virulence ones (+a, +b, +c and +d) and 16 genotypes consisting of four avirulence loci were considered, definite characteristics on determination of types of nonrandom associations appeared depending on the number of susceptibility genes [S0, S1, S2, S3 and S4 (subscript is the number of susceptibility genes)]. When, for example, a part of a host genotype S0 (ABCD) was replaced by another host genotype S2 (for example, AB++), that is, (S0→S2), nonrandom association patterns, NCCCCC, CNCCCC, CCCNCC, CCNCCC, CCCCNC and CCCCCN, were observed for host genotypes AB++, A+C+, +BC+, A++D, +B+D and ++CD belonging to S2, respectively. NCCCCC is a nonrandom association type for interactions between avirulence loci, a-b, a-c, a-d, b-c, b-d, and c-d, respectively. For determination of the patterns, there were two cases; in some cases a new host genotype (genotype after the replacement; called receptor, for convenience, in the simulations) gave influence, and in other cases, it was the old host genotype (genotype before replacement; donor in the simulations). In the former cases, combinations of a resistance gene and a susceptibility gene induced a cross-type nonrandom association, and combinations between a resistance gene and another resistance gene and between a susceptibility gene and another susceptibility gene induced noncross-type nonrandom association. In contrast, when a host genotype (S2) was changed to S0, the pattern became to be reversed, that is, CNNNNN, NCNNNN, NNNCNN, NNCNNN, NNNNCN and NNNNNC, respectively, in the above example.
    Download PDF (1026K)
  • Shigehisa KIYOSAWA, Donna PURBA, Md. Shamsher ALI, Yasushi OKINAKA, Ts ...
    1996 Volume 62 Issue 2 Pages 101-107
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The influence of replacement between host genotypes with different S groups (groups with a different number of resistance or susceptibility genes) on the types and patterns of nonrandom associations between avirulence loci in the pathogen was examined by a method of simulation. Through all combinations of S groups, nonrandom association patterns are largely influenced by various factors, and degrees of influence are in the following order. 1) Direction of transfer of values from donor to receptor (replacement of varieties with different genotypes from old to new), 2) combinations of S groups (groups having the different number of susceptibility genes), 3) fitness values given to virulence genes when various values with the same average are given, 4) generations of vegetative reproduction, and 5) the number of resistance loci with complementary resistance and susceptibility genes. When a large area was replaced by a new host genotype with one or three different genes, half of the possible six nonrandom associations were cross (C)-type and the remainder were noncross (N)-type. In these cases, combinations of an avirulence gene corresponding to a resistance gene in the new host genotype with other avirulence loci in the pathogen show N-type nonrandom associations. If a receptor has two resistance genes, combinations including one of avirulence loci corresponding to resistance genes in the receptor induce C-type nonrandom associations and combinations including the two loci show N type. Accordingly, the ratio of N:C was 2:4. When a receptor has three resistance genes, the ratio is 3:3. This can explain why two types were found in fields where two or more statistically significant nonrandom associations were found.
    Download PDF (1131K)
  • Seiya TSUSHIMA, Hideki NAITO, Motoo KOITABASHI
    1996 Volume 62 Issue 2 Pages 108-113
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Rice plants were inoculated by spraying with Pseudomonas glumae, the causal agent of bacterial grain of rice, at different times before heading time to study population dynamics of the pathogen on rice sheaths in the field and the relationship between the population size and the disease incidence. The bacterial population on the uppermost leaf sheaths and flag leaf sheaths were detected periodically using the selective S-PG medium. The results indicate that the rate of leaf sheaths with pathogen population of more than 103cfu/g fresh weight, which was the detection limit of the selective medium, decreased greatly with the growth of internode. Bacterial populations on individual leaf sheaths varied from leaf sheath to leaf sheath showing approximately lognormal distribution by plotting data sets on the cumulative probability scale. The fact suggests that the bacterial populations on uppermost leaf sheaths in the field may be estimated from lognormal value of population size on individual leaf sheaths more accurately than from bulked leaf sheath samples. Correlation coefficient between detection frequency of the pathogen on flag leaf sheaths and disease incidence on panicles a week after heading time was high (r=0.78, p=0.01), but not significant 2 and 3 weeks after heading time, suggesting that the pathogen on flag leaf sheaths is important in primary infection of the disease. The value of frequency is applicable for estimation of disease incidence of bacterial grain rot of rice in the field.
    Download PDF (827K)
  • Tsuneo NAMAI, Manabu NUKINA, Jiro TOGASHI
    1996 Volume 62 Issue 2 Pages 114-118
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    This study was undertaken to investigate the effects of two toxins and a derivative of one toxin produced by rice blast fungus, Pyricularia oryzae (Magnaporthe grisea), on infection to rice plants. The inner epidermal tissue of a detached rice leaf sheath was pre-treated with three compounds and an incompatible race of this fungus was challenge-inoculated. All compounds used in this study, tenuazonic acid, pyriculol and dihydro derivative of pyriculol (dihydropyriculol) induced susceptibility to pre-treated tissues on the infection of this fungus at concentrations greater than 20μg/ml. The most effective toxin was pyriculol, and tenuazonic acid was followed. Only dihydropyriculol was detected in the germination fluid of the conidia of this fungus with HPLC.
    Download PDF (797K)
  • Nobuyuki YOSHIKAWA, Kazutoshi SASAMOTO, Manabu SAKURADA, Tsuyoshi TAKA ...
    1996 Volume 62 Issue 2 Pages 119-124
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    By means of polymerase chain reactions, nucleotide sequence analyses of the 3'-terminal regions, and amino acid sequence analyses, two capillovirus isolates, apple stem grooving (ASGV) and citrus tatter leaf virus (CTLV) were found from virus culture V3 obtained from a single shoot of Japanese pear (Pyrus serotina). V3 was originally presumed to be a pure culture of ASGV. The two isolates that were eventually determined to be different capilloviruses were designated V3-1 and V3-2, respectively. V3-1 differed from ASGV reference isolate P-209 from apple by only 3 base substitutions in the 3'-terminal 2611 nucleotides. V3-2 was closer to CTLV reference isolates Li-23 (95.9% homology) and L (95.6% homology) from lilies in the sequence of its 3'-terminal 1669 nucleotides than it was to that of ASGV isolate P-209 (89.1% homology). In the comparison of ORF2 proteins (313 amino acids, aa) the similarity between as sequences of V3-2 and P-209 was 94.8%, while that between V3-2 and CTLV isolates (Li-23 and L) was 97.4%. In the case of the as sequence homology of the putative coat protein regions (237 aa), equivalent to the C-terminal region of ORF1 protein, the similarity between V3-2 and P-209 was 97.5% and was 99.2% between V3-2 and CTLV isolates (Li-23 and L). The most striking difference in aa sequence homologies was found in the ORF1 protein (277 aa) encoding ORF2 in the other frame. The similarity between V3-1 and P-209 was 99.3%, while that between V3-2 and P-209 was 61.0%. Isolate V3-2 shared 85.6% and 93.8% aa sequence homologies with Li-23 and L, respectively. Solely on the basis of comparison of nucleotide and amino acid sequences of Japanese pear isolates V3-1 and V3-2 with reference isolates, we conclude that V3-1 is almost identical to an ASGV reference isolate from apple, while V3-2 is similar to CTLV reference isolates from lilies. We recommend that CTLV be considered as a strain of ASGV.
    Download PDF (1879K)
  • Yasufumi HIKICHI, Akira SAITO, Kazumi SUZUKI
    1996 Volume 62 Issue 2 Pages 125-129
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Sections of middle head leaf of lettuce were stained with fluorescein isothiocyanate-conjugated antibody against Pseudomonas cichorii, a causal agent of bacterial rot of lettuce, and were observed under a fluorescent microscope. Fluorescent antibody-labeled P. cichorii cells were observed in stomata of the sections, which did not contain browing symptom of the disease. Special fluorescent specks derived from P. cichorii were most frequently observed in guard cells and intercellular spaces of substomatal cavities. Browing, which was the initial symptom of disease, progressed from epidermis to mesophyll. In advance of progress of browing symptom, specific fluorescent specks were observed in intercellular spaces of epidermis and then were observed in intercellular spaces of mesophyll. These results suggested that P. cichorii first invaded head leaf of lettuce through stomata, later multiplied in intercellular spaces of epidermis and colonized intercellular spaces of mesophyll. Specific fluorescent specks were also observed in leaf hairs.
    Download PDF (4077K)
  • Koji KAGEYAMA, Misako TACHI, Masakazu UMETSU, Mitsuro HYAKUMACHI
    1996 Volume 62 Issue 2 Pages 130-133
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pythium sulcatum was a predominant species isolated from carrot lesions showing brown-blotted root rot, and induced the similar symptoms to those naturally occurring in carrot fields with artificial inoculation. The fungus was also isolated from asymptomatic storage and absorbing roots from seedling to harvest stage, especially during spring cropping season. The infection sites of P. sulcatum was the upper part of asymptomatic storage roots in which the blotted lesion might appear. P. ultimum, P. sylvaticum, P. coloratum and P. spinosum were also obtained from asymptomatic roots and residues of root or leaf, but these species showed slight pathogenicity. The absorbing root residue was found to be the primary infection source of P. sulcatum. P. sulcatum was widespread in the intensive carrot-cultivated area.
    Download PDF (732K)
  • Karden MULYA, Minoru WATANABE, Masao GOTO, Yuichi TAKIKAWA, Shinji TSU ...
    1996 Volume 62 Issue 2 Pages 134-140
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pseudomonas fluorescens strain PfG32 isolated from the rhizosphere of the onion actively suppressed the occurrence of bacterial wilt disease of tomato (BWT) in vermiculite amended natural soil and produced antibiotic substance(s) and siderophore. To investigate the role of the substances in the biocontrol, several mutants defective in antibiotic substances or Siderophore production were isolated from spontaneous Rifr mutant, PfG32R, by Tn5 insertion. Based on pot experiment, the suppression of BWT by Ant-Sid+ (antibiotics non-producing but siderophore producing) mutants was lower compared to its parental strain and to Ant+Sid- (siderophore non producing but antibiotics producing) mutants. However, Ant-Sid+ mutants still express a significant effect. The suppression of BWT by PfG32R was correlated to the suppression of the population of the pathogen observed on the surface of root and to the delay of appearance of detectable population of the pathogen in root tissues. We consider that the ability of PfG32 to produce antibiotics and siderophore is the important factor on determining its biological control and other factor may act as secondary factor.
    Download PDF (1962K)
  • Yasufumi HIKICHI, Akira SAITO, Kazumi SUZUKI
    1996 Volume 62 Issue 2 Pages 141-146
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Leaves of lettuce (Lactuca sativa L. cultivar Success) were dipped in a solution of Pseudomonas cichorii. Population of P. cichorii on leaves incubated at 30°C was 1.3×108cfu/g fresh weight 7 days after inoculation and disease incidence of bacterial rot of lettuce was severe. The bacterial population on leaves, which were incubated at 20°C, was less than 105cfu/g fresh weight, and disease incidence was slight. Lettuce plants were cultivated in a field, in which many lettuce plants had been severely infected with P. cichorii at any year, in Ichinohe-machi, Iwate Prefecture. P. cichorii had been isolated at the low density from soil since 37 days before transplanting. P. cichorii was isolated at the low density from entire plants before head formation. The bacterial population on leaves during head formation is lognormally distributed, and bacterial rot was detected on the bulked leaves, from which P. cichorii was isolated at the density of above 105cfu/g fresh weight. The bacterial populations increased on outerleaves and head-leaves in the early stage and the middle stage of head formation, respectively. The bacterial population on head-leaves positively correlated with that on outer-leaves. The percentage of lettuce plants with diseased head-leaves positively correlated with that with diseased outer-leaves. Therefore. P. cichorii exists on leaves of lettuce during head formation as the epiphytic bacterium and disease symptom is detected on the leaf in which population of P. cichorii is above 105cfu/g fresh weight. P. cichorii, with which outer-leaves are infected, is an important infection source of the disease on head-leaves.
    Download PDF (1736K)
  • Kimiko KURADATE, Kiyoshi NAMAI, Atsushi MIYASAKA, Koji KATSURA, Kumiko ...
    1996 Volume 62 Issue 2 Pages 147-152
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Total RNAs obtained from 26 isolates of 6 anastomosis groups (AGs) of Rhizoctonia solani were analyzed by Northern hybridization using the cloned fragment of the plasmid DNAs as the probes. Plasmid-encoded transcripts were found in all the plasmid containing isolates of R. solani. The sizes of the transcripts were distributed among 6 AGs of R. solani as follows: 6.8kb in AG1 IB, 2.8kb and 1.2kb in AG2-2 IIIB, 7.6kb and 2.7kb in AG2-2 IV, 5.8kb in AG3, 0.5kb in AG4, 3.6kb in AG5, and 8.0kb in AG6. Considerable sequence homology was observed among plasmid-encoded transcripts obtained from isolates of the same AG, but no sequence homology was found among transcripts obtained from isolates of different AGs and from isolates within the same AG which contain no plasmid.
    Download PDF (1892K)
  • Mitsue DOHGO, Hideyoshi TOYODA, Yoshinori MATSUDA, Kazuhiko MATSUDA, Y ...
    1996 Volume 62 Issue 2 Pages 153-155
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Shigeo NAKAMURA, Takayoshi IWAI, Ryoso HONKURA, Masashi UGAKI, Yuko OH ...
    1996 Volume 62 Issue 2 Pages 156-160
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Koji AZEGAMI
    1996 Volume 62 Issue 2 Pages 161-166
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Jun ISOTA, Yoshiyuki KADOWAKI, Sakae ARASE
    1996 Volume 62 Issue 2 Pages 167-169
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Toyozo SATO, Susumu UEDA, Akihiko IIJIMA, Nobuo TEZUKA
    1996 Volume 62 Issue 2 Pages 170-174
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Mitsuro KAMEYA-IWAKI, Yoichi SUZUKI, Kaoru HANADA, Shinichi ITO, Shuhe ...
    1996 Volume 62 Issue 2 Pages 175-176
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Mamoru SATO, Shigetou NAMBA, Maki KATSUHARA, Hiromu KAWAKITA, Wataru M ...
    1996 Volume 62 Issue 2 Pages 177-180
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Yuichiro MURAI, Masao GOTO
    1996 Volume 62 Issue 2 Pages 181-183
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Akira SHIRATA
    1996 Volume 62 Issue 2 Pages 185-193
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    It has been reported that P. tolaasii S8501 isolated in Japan caused bacterial rot of oyster mushroom (Pleurotus ostreatus, Japanese name: ‘Hiratake’) and produced 8 kinds of toxin as pathogenic factor. Tolaasin I, the main toxin, plays an important role in the development of the symptom on the fruit bodies of ‘Hiratake’ and Flammulina velutipes (‘Enokitake’). P. tolaasii S8501 was found to produce volatile components on ‘Hiratake’ after inoculation. These components were different from the above toxins, and induced rot to the fruit body of ‘Hiratake’. As it is considered that they are one of the pathogenic factors of P. tolaasii, the volatile components were named tentatively as “tovsin” in this report. Tovsin caused browning and rotting to mushrooms, and inhibited germination of plants' seeds and growth of phytopathogenic fungi such as Rosellinia necatrix, but showed little growth inhibition to bacteria. The intensity of tovsin activity was determined based on its degree of inhibition to the germination of lettuce seeds within one or two days. Quantity of tovsin produced by P. tolaasii depends on the mushroom species and media: a large quantity is produced on ‘Hiratake’ but a little on ‘Enokitake’, and also more can be produced on King's medium B but little on PDA medium. Production of tovsin was inhibited by addition of glucose. Tovsin could be trapped at 0 and -20°C, was basic, with stimulating smell, stable at 100°C, and induced or produced many crystals in King's medium B. These results suggest that tovsin promote the disease of ‘Hiratake’ in cultivating rooms and in packs after harvest.
    Download PDF (3185K)
  • Hiromitsu FURUYA, Tsutomu MATSUMOTO
    1996 Volume 62 Issue 2 Pages 194-198
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The development of eyespot disease of winter wheat by Pseudocercosporella herpotrichoides (Fron) Deighton in a field in Akita, Japan was studied in 1983/84 with snow cover having a depth exceeding 10cm for 12 weeks. Wheat had been continuously grown for 6 years and eyespot disease occurred intensively in the previous growing season in the field. Plants with eyespot lesions in leaf sheaths increased up to 70% by the middle of December, shortly before the start of prolonged snow cover. Conidial dispersal of the pathogen was observed from October to December. The development of the lesion appeared to originate from direct infection of dispersed conidia, and infection of coleoptiles scarcely caused the infection of leaf sheaths. During the period of this cover, eyespot lesions seemed to have increased in size and number per plant and penetrated several inner leaf sheaths. Infection of culms started at 5 weeks following the end of the cover and reached almost all culms infected within the next 6 weeks. It is suggested that most of the infection of culms resulted from the development of the disease originally dispersed to the outermost leaf sheaths before the snow cover.
    Download PDF (1659K)
  • Yukio HARADA, Toshitaka IWAMA, Tatsuo FUKUDA
    1996 Volume 62 Issue 2 Pages 199-201
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Puccinia chrysanthemi on Chrysanthemum morifolium has been described as a hemi-form rust with uredinial and telial states. However, spermogonial state was found on leaves of C. morifolium inoculated with teliospores and also on infected leaves of C. morifolium collected from fields in early summer. P. chrysanthemi, therefore, has a brachy-form life cycle and is an autoecious species. In teliospore germination, two kinds of basidia were observed; the one with a binucleate cell and two uninucleate cells, the other with four uninucleate cells. Both binucleate and uninucleate basidiospores were formed.
    Download PDF (1168K)
  • Kazuyuki CHATANI, Hideyoshi TOYODA, Yoko OGATA, Kazuharu KOREEDA, Kenj ...
    1996 Volume 62 Issue 2 Pages 202-206
    Published: April 25, 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In an attempt to produce the powdery mildew and black spot disease resistant rose plants (Rosa hybrida), we established an efficient inoculation system for precise evaluation of the resistance or susceptibility of rose cultivars to those diseases. In this system, the top leaflets of fourth trifoliate leaves generated from lateral buds of rose cuttings were used for inoculation with conidiospores of Sphaerotheca pannosa or Diplocarpon rosae. Two cultivars, “Paul's Pink” and “Magic”, were found to be strongly resistant to the powdery mildew pathogen and the “C line” of wild rose (R. multiflora) was highly resistant to both powdery mildew and black spot pathogens. These results suggest that the wild rose would be a useful gene source for providing a true disease resistance to commercially valuable cultivars of rose.
    Download PDF (792K)
  • 1996 Volume 62 Issue 2 Pages e1
    Published: 1996
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Download PDF (27K)
feedback
Top