Time filter

Source Type

Itou M.,Kochi Agricultural Research Center | Watanabe M.,Hiroshima University | Watanabe E.,Hiroshima University | Miura K.,Hiroshima University | Miura K.,Japan National Agriculture and Food Research Organization
Entomological Science | Year: 2013

Nesidiocoris tenuis is considered to make significant contributions to the control of greenhouse pests such as whiteflies, thrips, leafminers, lepidopterans, and spider mites, although there is little information based on direct observation of the predation of N. tenuis on these target pests. We developed a method to perform gut content analysis of N. tenuis based on DNA in which specific PCR primers were designed to detect the DNA of target pests. By means of gut-content analysis, we found that the percentage of N. tenuis preying on Bemisia tabaci and Thrips palmi was approximately 40% in the field. © 2012 The Entomological Society of Japan.

Horita M.,Japan National Institute for Agro - Environmental Sciences | Tsuchiya K.,Kyushu University | Suga Y.,Nagasaki Pest Control Station | Yano K.,Kochi Agricultural Research Center | And 3 more authors.
Journal of General Plant Pathology | Year: 2014

Ralstonia solanacearum is the causal organism of bacterial wilt of more than 200 species representing 50 families of plants in tropical, subtropical, and warm temperate regions in the world. Traditionally classified into five races based on differences in host range, R. solanacearum has also been grouped into six biovars on the basis of biochemical properties. With recent developments in molecular biology, various DNA-based analyses have been introduced and used to confirm that this binary system does not completely represent the diversity within R. solanacearum strains. Therefore, a new hierarchical classification scheme has been suggested, which defines R. solanacearum as a species complex and reorganized the concept of the species as a monophyletic cluster according to a phylogenetic analysis based on genomic sequence data. Here we discuss the current bacterial wilt situation and genetic relationships based on the recent classification system of Japanese R. solanacearum strains as well as worldwide strains. We also review the genetic, biochemical, and pathological characteristics of R. solanacearum strains, in particular, those affecting potato and Zingiberaceae plants as distinctly important pathogens in relation to continuously problematic and recent emergent diseases in Japan. © 2014, The Phytopathological Society of Japan and Springer Japan.

Shimomoto Y.,Kochi Agricultural Research Center | Kobayashi K.,Ehime University | Okuda M.,Japan National Agriculture and Food Research Organization
Journal of General Plant Pathology | Year: 2014

In 2007, lisianthus (Eustoma grandiflorum) plants with necrotic ringspots on the leaves were found in Kochi Prefecture, Japan. Tospovirus-like spherical enveloped particles with ca. 160 nm in diameter were observed with electron microscopy. The complete nucleotide sequence of the S RNA segment of the virus was determined, and phylogenetic analysis using deduced amino acid sequences of the nucleocapsid protein and the nonstructural S protein indicated that the virus is phylogenetically distinct from any known tospovirus species. The results suggest that the virus is a new member of the genus Tospovirus, in the family Bunyaviridae. The virus is the fifth distinct tospovirus occurring naturally in lisianthus in Japan. The necrotic symptoms were reproduced on lisianthus seedlings after mechanical inoculation. The host range of the virus isolate on several test plants was also examined. © 2014 The Phytopathological Society of Japan and Springer Japan.

Sekine K.-T.,Iwate Biotechnology Research Center | Tomita R.,Iwate Biotechnology Research Center | Takeuchi S.,Kochi Agricultural Research Center | Atsumi G.,Iwate Biotechnology Research Center | And 7 more authors.
Molecular Plant-Microbe Interactions | Year: 2012

The N' gene of Nicotiana sylvestris and L genes of Capsicum plants confer the resistance response accompanying the hypersensitive response (HR) elicited by tobamovirus coat proteins (CP) but with different viral specificities. Here, we report the identification of the N' gene. We amplified and cloned an N' candidate using polymerase chain reaction primers designed from L gene sequences. The N' candidate gene was a single 4143 base pairs fragment encoding a coiled-coil nucleotide-binding leucine-rich repeat (LRR)-type resistance protein of 1,380 amino acids. The candidate gene induced the HR in response to the coexpression of tobamovirus CP with the identical specificity as reported for N'. Analysis of N'-containing and tobamovirus-susceptible N. tabacum accessions supported the hypothesis that the candidate is the N' gene itself. Chimera analysis between N' and L3 revealed that their LRR domains determine the spectrum of their tobamovirus CP recognition. Deletion and mutation analyses of N' and L3 revealed that the conserved sequences in their C-terminal regions have important roles but contribute differentially to the recognition of common avirulence proteins. The results collectively suggest that Nicotiana N' and Capsicum L genes, which most likely evolved from a common ancestor, differentiated in their recognition specificity through changes in the structural requirements for LRR function. © 2012 The American Phytopathological Society.

Gappa-Adachi R.,Kochi Agricultural Research Center | Gappa-Adachi R.,Kochi Prefecture Crop Pest Control Center | Morita Y.,Kochi Agricultural Research Center
Journal of General Plant Pathology | Year: 2013

In 2010, a bacterial soft rot was found on myoga [Zingiber mioga (Thunb.) Rosc.] in Japan. Initial small spots on flower buds rapidly enlarged while changing from light brown to brown. Diseased flower buds became completely rotten. Several bacteria isolated from the diseased tissues caused the same symptoms as those observed in the fields and were reisolated from the tissue. These bacteria were identified as Erwinia chrysanthemi and were classified into subdivision IV and biovar 3. This is the first report of bacterial soft rot of myoga in the world. © 2013 The Phytopathological Society of Japan and Springer Japan.

Inami K.,Tokyo University of Agriculture and Technology | Yoshioka-Akiyama C.,Tokyo University of Agriculture and Technology | Morita Y.,Kochi Agricultural Research Center | Yamasaki M.,Tokyo University of Agriculture and Technology | And 3 more authors.
PLoS ONE | Year: 2012

Compatible/incompatible interactions between the tomato wilt fungus Fusarium oxysporum f. sp. lycopersici (FOL) and tomato Solanum lycopersicum are controlled by three avirulence genes (AVR1-3) in FOL and the corresponding resistance genes (I-I3) in tomato. The three known races (1, 2 and 3) of FOL carry AVR genes in different combinations. The current model to explain the proposed order of mutations in AVR genes is: i) FOL race 2 emerged from race 1 by losing the AVR1 and thus avoiding host resistance mediated by I (the resistance gene corresponding to AVR1), and ii) race 3 emerged when race 2 sustained a point mutation in AVR2, allowing it to evade I2-mediated resistance of the host. Here, an alternative mechanism of mutation of AVR genes was determined by analyses of a race 3 isolate, KoChi-1, that we recovered from a Japanese tomato field in 2008. Although KoChi-1 is race 3, it has an AVR1 gene that is truncated by the transposon Hormin, which belongs to the hAT family. This provides evidence that mobile genetic elements may be one of the driving forces underlying race evolution. KoChi-1 transformants carrying a wild type AVR1 gene from race 1 lost pathogenicity to cultivars carrying I, showing that the truncated KoChi-1 avr1 is not functional. These results imply that KoChi-1 is a new race 3 biotype and propose an additional path for emergence of FOL races: Race 2 emerged from race 1 by transposon-insertion into AVR1, not by deletion of the AVR1 locus; then a point mutation in race 2 AVR2 resulted in emergence of race 3. © 2012 Inami et al.

Okazaki S.,Forestry and Fisheries Research Center | Okuda M.,Japan National Agricultural Research Center | Komi K.,Kochi Agricultural Research Center | Yamasaki S.,Forestry and Fisheries Research Center | And 3 more authors.
Australasian Plant Pathology | Year: 2011

The acquisition efficiency of Tomato spotted wilt virus (TSWV) by Frankliniella occidentalis was examined using TSWV-infected Datura stramonium with various virus titres. TSWV quantities in leaves were measured using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The percentages of viruliferous F. occidentalis significantly correlated with DAS-ELISA and qRT-PCR values in the fed leaf piece. The detectable period of TSWV in viruliferous F. occidentalis adults trapped on sticky traps was also examined at various temperatures. At 25°C or less, TSWV could still be detected by DAS-ELISA in the bodies for at least 20 days after the capture of viruliferous F. occidentalis, although ELISA values had decreased gradually over time more rapidly at higher temperatures. The quantities of TSWV RNA detected by qRT-PCR rapidly decreased. The mean value decreased to half in a day, and reduced to 7.3% of the initial mean value after 14 days. © 2010 Australasian Plant Pathology Society Inc.

Shimomoto Y.,Kochi Agricultural Research Center | Kiba A.,Kochi University | Hikichi Y.,Kochi University
Journal of General Plant Pathology | Year: 2015

Some isolates of Corynespora cassiicola from eggplant leaves with black blight can also cause Corynespora blight on sweet pepper. To differentiate eggplant isolates differing in virulence to sweet pepper, we first created two sets of primers based on nucleotide sequences of DNA fragments specific to virulent and to avirulent isolates, respectively, in a random amplified polymorphic DNA analysis using two random primers. A multiplex polymerase chain reaction using the two primer sets allowed us to discriminate isolates virulent to sweet pepper from among eggplant isolates. © 2015, The Phytopathological Society of Japan and Springer Japan.

Gappa-Adachi R.,Kochi Agricultural Research Center | Gappa-Adachi R.,Kochi Prefecture Crop Pest Control Center | Yano K.,Kochi Agricultural Research Center | Takeuchi S.,Kochi Agricultural Research Center | And 2 more authors.
Journal of General Plant Pathology | Year: 2012

In 2004, a damping-off symptom was found on southern star, Oxypetalum caeruleum, in Kochi Prefecture, Japan. Two Phytophthora strains with different colony patterns on potato dextrose agar were isolated, and their pathogenicity was confirmed by inoculation of southern star plants and their reisolation from symptomatic plants. Both fungi were identified as Phytophthora palmivora based on morphology, physiology, and sequence analysis of the internal transcribed spacers of nuclear ribosomal DNA. This is the first report of Phytophthora blight of southern star in the world. © 2011 The Phytopathological Society of Japan and Springer.

Nagasaka K.,Japan National Agricultural Research Center | Takahasi N.,Kochi Agricultural Research Center | Okabayashi T.,Kochi Prefectural Government
Applied Entomology and Zoology | Year: 2010

In order to elucidate the impact of secondary parasitism on a banker plant system, aphid parasitoids on banker plants were surveyed for four years in commercial greenhouses producing eggplant and sweet pepper in Kochi Prefecture, Japan. A banker plant system using Aphidius colemani was introduced into the greenhouses in November or December for the control of pest aphids from February through May. The mean rate of secondary parasitoids to total parasitoids on the alternative host aphid (Rhopalosiphum padi) on banker plants was less than 35% in the early season. In March or April, the mean rate exceeded 40%, and was more than 70% by May or June. Three main species of secondary parasitoids, Alloxysta sp. nr victrix, Dendrocerus laticeps and Syrphophagus sp., occurred throughout the season. In addition, Asaphes suspensus and Pachynouron aphidis occurred later in the season. In greenhouses where the banker plant system of aphid control failed, the increase of secondary parasitism on banker plants was sharper than in greenhouses with successful aphid control. In March and April, the higher rates of secondary parasitism on banker plants had a significant influence on the failure of aphid control.

Loading Kochi Agricultural Research Center collaborators
Loading Kochi Agricultural Research Center collaborators