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21.
Optimal charcoal concentrations were examined for tuff formation of SBIs （single-basidiospore isolates） obtained from Rhizoctonia solani AG-1 IC, AG-2-2 IV and AG-2-3, and SPIs （single-protoplast isolates） from AG-1 IA by using PDCA with different charcoal concentrations. The best charcoal concentration for SBIs from AG-1 IC was 0.5%, from AG-2-3 was 1%, and from AG-2-2 IV was 2%. The optimal concentration was 0% for SPIs from AG-1 IA. The optimal charcoal concentrations used for tuff formation between SBIs and between SPIs are quite varied, depending on the different AGs. The results of AFLP haplotypes suggest that tuff isolates formed between SBIs/SPIs are heterokaryon. 相似文献
22.
Differentiation of Rhizoctonia AG-D Isolates from Turfgrass into Subgroups I and II Based on rDNA and RAPD Analyses 总被引：1，自引：0，他引：1
Takeshi Toda Mitsuro Hyakumachi Haruhisa Suga Koji Kageyama Akemi Tanaka Toshikazu Tani 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(9):835-846
Binucleate Rhizoctonia anastomosis group (AG) D is the cause of rhizoctonia-patch and elephant-footprint diseases of zoysiagrass, and winter-patch disease of bentgrass. Rhizoctonia AG-D is also known as the causal pathogen of other diseases such as sharp-eye-spot of cereals, foot-rot of cereals and winter-stem-rot of mat rush. Isolates of AG-D have been divided into the two subgroups AG-D (I) and AG-D (II), based on the results of cultural characteristics and pathogenicity tests. Isolates obtained from zoysiagrass exhibiting symptoms of rhizoctonia-patch disease, from bentgrass with winter-patch disease, from wheat with foot-rot disease, and from mat rush with winter-stem-rot disease were reported to belong to subgroup AG-D (I). On the other hand, isolates obtained from zoysiagrass with elephant-footprint disease were assigned to subgroup AG-D (II). To confirm the existence of these two subgroups in AG-D, the genetic structure of AG-D isolates from turfgrass and other crops was compared. RFLP analysis of the ITS region from rDNA after digestion with the restriction enzymes EcoRI, HaeIII, HhaI, HinfI, and MboI separated AG-D isolates into two groups corresponding to AG-D (I) and AG-D (II). Furthermore, other AGs except AG-Q (AGs-A, Ba, Bb, C, E, F, G, I, K, L, O, P, and R. solani AG1-IC) did not have the same patterns that were seen for the two AG-D subgroups. AG-Q isolates from bentgrass showed the same patterns as AG-D (I). The results of the RAPD analysis also revealed the existence of two groups that corresponded to AG-D (I) and AG-D (II). These analyses revealed that Rhizoctonia AG-D isolates from turfgrass could be divided into two subgroups consistent with those based on cultural characteristics and pathogenicity. In addition, isolates of foot-rot disease of wheat and isolates of winter-stem-rot disease of mat rush whose cultural characteristics were the same as those of AG-D (I) also showed similar RFLP and RAPD patterns to those of AG-D (I) isolates from turfgrass. 相似文献
23.
ABSTRACT (14)C-labeled chlamydospores of Fusarium solani f. sp. phaseoli were exposed to soil at 5, 15, 25, or 30 degrees C at pH 5 or 8 and water potential of -1 kPa or to soil at 0, -1, or -10 kPa at 25 degrees C at pH 6.9. Total carbon loss was greatest at 25 or 30 degrees C at pH 8 and -1 kPa. (14)CO(2) from respiration of chlamydospores and from soil microbes utilizing chlamydospore exudates accounted for the largest share of total carbon loss under all conditions. (14)(CO)(2) from soil microbial metabolism of (14)CO(2) exudates of chlamydospores was greatest in soil at 15, 25, and 30 degrees C, pH 8, and at either -1 or -10 kPa. Chlamydospore germinability in the absence of a C source (nutrient independence), viability in potato-dextrose broth, and virulence to kidney bean declined rapidly after exposure to soil at high temperatures (25 and 30 degrees C), pH 8, and the higher matric potentials (0 to-1 kPa). By contrast, germinability remained high (>50%), as did virulence, in soil at 5 degrees C and -10 kPa even after 70 days of incubation. Carbon loss was inversely correlated with germinability, viability, and virulence after exposure to soil at different pH levels, temperatures, and matric potentials. 相似文献
24.
Miyazawa M Kawazoe H Sumi Y Hyakumachi M 《Journal of agricultural and food chemistry》2003,51(7):1880-1883
Lytic activity of l-menthol (1) derivatives [(-)-(1S,3R,4S,6S)-6-hydroxymenthol (2), (-)-(1S,3R,4S)-1-hydroxymenthol (3), and (+)-(1S,3R,4R,6S)-6,8-dihydroxymenthol (4)] against the snow blight disease fungus, Micronectriella nivalis was investigated. Compounds 2, 3, and 4 had 85.0, 63.9, and 81.9% lytic activity, respectively, at a concentration of 0.2 mg/mL. The activity of each of the three compounds increased in a dose-response manner. To study the structure-activity relationship, acetyl esters of 1-4 [(-)-menthyl acetate (1Ac), (-)-6-hydroxymenthyl diacetate (2Ac), (-)-1-hydroxymenthyl 3-monoacetate (3Ac), and (-)-6,8-dihydroxymenthyl 3,6-diacetate (4Ac)] were synthesized with yields of 80.2-99.8% and were also assayed. The acetyl esters of 1Ac, 2Ac, 3Ac, and 4Ac had 51.2, 91.5, 66.0, and 95.2% lytic activity, respectively, at a concentration of 0.2 mg/mL, and these compounds showed further high lytic activity compared with the alcohols of 1-4. These acetyl esters also showed higher lytic activity as their concentration was increased. Of particular interest is the fact that 2Ac and 4Ac both had higher lytic activity at 0.05-0.2 mg/mL compared with copper 8-hydroxyquinolate, a standard chemical widely used to control snow blight. This is the first report on lytic activity of l-menthol derivatives. 相似文献
25.
Yasuo Yamagiwa Yoshishige Inagaki Yuki Ichinose Kazuhiro Toyoda Mitsuro Hyakumachi Tomonori Shiraishi 《Journal of General Plant Pathology》2011,77(6):336-341
A plant-growth-promoting fungus (PGPF), Talaromyces sp. was isolated from an agricultural field in southwestern Japan. We found that this fungus emitted several terpenoid-like
volatiles including β-caryophyllene. Then we investigated the effect of β-caryophyllene on promoting the growth and inducing resistance of Brassica campestris L. var. perviridis. The compound significantly enhanced the growth of seedlings and their resistance to Colletotrichum higginsianum. On the basis of these results, we discuss the role of β-caryophyllene in the activities of PGPF. 相似文献
26.
Suga H Karugia GW Ward T Gale LR Tomimura K Nakajima T Miyasaka A Koizumi S Kageyama K Hyakumachi M 《Phytopathology》2008,98(2):159-166
Members of the Fusarium graminearum species complex are important cereal pathogens worldwide and belong to one of at least nine phylogenetically distinct species. We examined 298 strains of the F. graminearum species complex collected from wheat or barley in Japan to determine the species and trichothecene chemotype. Phylogenetic analyses and species-diagnostic polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLPs) revealed the presence and differential distribution of F. graminearum sensu stricto (s. str.) and F. asiaticum in Japan. F. graminearum s. str. is predominant in the north, especially in the Hokkaido area, while F. asiaticum is predominant in southern regions. In the Tohoku area, these species co-occurred. Trichothecene chemotyping of all strains by multiplex PCR revealed significantly different chemotype compositions of these species. All 50 strains of F. graminearum s. str. were of a 15- or 3-acetyl deoxynivalenol type, while 173 (70%) out of 246 strains of F. asiaticum were of a nivalenol type. The possibility of gene flow between the two species was investigated by use of 15 PCR-RFLP markers developed in this study. However, no obvious hybrids were detected from 98 strains examined, including strains collected from regions where both species co-occur. 相似文献
27.
Md. Motaher Hossain Farjana Sultana Mayumi Kubota Hiroyuki Koyama Mitsuro Hyakumachi 《Journal of General Plant Pathology》2008,74(3):213-221
The culture filtrate (CF) from the plant growth-promoting fungus Phoma sp. GS8-1 was found to induce systemic resistance in Arabidopsis thaliana against the bacterial leaf speck pathogen Pseudomonas syringae pv. tomato DC3000 (Pst), and the underlying mechanism was studied. Roots of A. thaliana were treated with CF from GS8-1, and plants expressed a clear resistance to subsequent Pst infection; disease severity was reduced, and proliferation of pathogen was suppressed. Various mutants of A. thaliana were used to test whether the CF induced resistance through one of the known signaling pathways: salicylic acid (SA), jasmonic
acid (JA), and ethylene (ET). The CF was fully protective against Pst in Arabidopsis mutants jar1 and ein2 similar to wild-type plants. However, its efficacy was reduced in plants containing transgene NahG. Examination of systemic gene expression revealed that CF modulates the expression of SA-inducible PR-1, PR-2 and PR-5 genes, the JA/ET-inducible ChitB gene, and the ET-inducible Hel gene. Moreover, the expression of these genes was further enhanced upon subsequent stimulation after attack by Pst. Our data suggest that in addition to a partial requirement for SA, the signals JA and ET may also play a role in defense
signaling in Arabidopsis. 相似文献
28.
Characterization of a New Subgroup of Rhizoctonia solani Anastomosis Group 1 (AG-1-ID), Causal Agent of a Necrotic Leaf Spot on Coffee 总被引：1，自引：0，他引：1
Priyatmojo A Escopalao VE Tangonan NG Pascual CB Suga H Kageyama K Hyakumachi M 《Phytopathology》2001,91(11):1054-1061
ABSTRACT A new foliar disease on coffee leaves was observed in Mindanao, Philippines, in 1996. The symptoms appeared as large circular or irregularly shaped necrotic areas with small circular necrotic spots (1 mm or less in diameter) usually found around the periphery of the large necrotic areas. Rhizoctonia solani was consistently isolated from these diseased coffee leaves. Isolates obtained were multinucleate (3 to 12 nuclei per hyphal cell), had an optimum temperature for hyphal growth at 25 degrees C, prototrophic for thiamine, and anastomosed with tester isolates belonging to R. solani anastomosis group 1 (AG-1). Mature cultures on potato dextrose agar (PDA) were light to dark brown. Sclerotia, light brown to brown, were formed on the surface of PDA and covered the whole mature colony culture. Individual sclerotia often aggregated into large clumps (3 to 8 mm in diameter) and their color was brown to dark brown. In pathogenicity tests, isolates from coffee caused necrotic symptoms on coffee leaves, whereas isolates of AG-1-IA (not isolated from coffee), 1-IB, and 1-IC did not. The results of analyses of restriction fragment length polymorphism of ribosomal DNA internal transcribed spacer, random amplified polymorphism DNA, and fatty acid profiles showed that R. solani isolates from coffee are a population of AG-1 different from AG-1-IA, 1-IB, and 1-IC. These results suggest that R. solani isolates from coffee represent a new subgroup distinct from AG-1-IA, 1-IB, and 1-IC. A new subgroup ID (AG-1-ID) is proposed. 相似文献
29.
A. Muslim Hayato Horinouchi Mitsuro Hyakumachi 《Journal of General Plant Pathology》2003,69(2):143-150
Four isolates of hypovirulent binucleate Rhizoctonia (HBNR) were evaluated for their ability to control Fusarium wilt of spinach (FWS) caused by Fusarium oxysporum f. sp. spinaciae (FOS). Fourteen-day-old spinach seedlings grown in paper pots with HBNR-amended soil (1% w/w ground barley grain inoculum)
were transferred to artificially pathogen-infested soil. Treatments with HBNR isolates significantly (P = 0.05) reduced disease and discoloration severity by 56%–100% and 52%–100%, respectively. The numbers of colony-forming
units of FOS per gram fresh weight in petioles or roots were reduced significantly (P = 0.01) in the plants treated with HBNR. HBNR isolates were well reisolated from the roots inside paper pots where they were
inoculated, whereas inconsistent colonization of HBNR was recorded from the roots outside paper pots where only pathogen was
inoculated. Root extracts from HBNR-treated and pathogen-challenged plants significantly inhibited germination and germling
length of FOS. The fresh weight of spinach leaves in the HBNR-treated plants increased significantly (P = 0.01), as much as 53%–63%, over the untreated and pathogen-challenged plants. This is the first report of biocontrol of
FWS by HBNR.
Received: July 18, 2002 / Accepted: October 22, 2002
Acknowledgments We are grateful to Dr. Komada for providing nonpathogenic Fusarium F13. The senior author (A.M.) thanks the Ministry of Education, Culture, Sports, Science, and Technology (Monbukagakusho)
Japan, for financial assistance. 相似文献
30.
Gladys Wairimu Karugia Haruhisa Suga Liane Rosewich Gale Takashi Nakajima Akihisa Ueda Mitsuro Hyakumachi 《Journal of General Plant Pathology》2009,75(2):110-118
Genetic subdivision of Fusarium asiaticum was investigated using a collection of 478 isolates originating from the Kyushu area and Aichi Prefecture, Japan and Zhejiang
Province in China. Trichothecene-type determination by a multiplex PCR-test indicated that all isolates were either of a nivalenol
(NIV) or a 3-acetyl deoxynivalenol (3ADON) type. The 15-acetyl deoxynivalenol (15ADON) type was not detected in this collection.
Based on a Bayesian model-based clustering method using allele data obtained with 11 variable number of tandem repeats (VNTR)
markers, we detected three genetic clusters. The majority of isolates in the clusters were NIV isolates from both Japan and
China, Japanese 3ADON and Chinese 3ADON isolates, respectively. High levels of fixation indices and low levels of effective
number of migrants were observed between the genetic clusters. Data was re-analyzed by classifying the isolates into six groups
according to trichothecene type and geographic location. Population analyses of these re-classified groups indicated that
the genetic subdivisions of F. asiaticum were correlated with both trichothecene type and geographic differences.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献