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Mizumoto H.,Kochi University | Nakamura I.,Kochi University | Shimomoto Y.,Kochi Prefectural Agriculture Research Center | Sawada H.,Kochi Agricultural College | And 6 more authors.
Molecular Plant Pathology

In pepper plants (genus Capsicum), the resistance against Tobamovirus spp. is conferred by L gene alleles. The recently identified L variant L1a can recognize coat proteins (CPs) of Tobacco mild green mosaic virus Japanese strain (TMGMV-J) and Paprika mild mottle virus Japanese strain (PaMMV-J), but not of Pepper mild mottle virus (PMMoV), as the elicitor to induce resistance at 24°C. Interestingly, L1a gene-mediated resistance against TMGMV-J, but not PaMMV-J, is retained at 30°C. This observation led us to speculate that L1a can discriminate between CPs of TMGMV-J and PaMMV-J. In this study, we aimed to determine the region(s) in CP by which L1a distinguishes TMGMV-J from PaMMV-J. By using chimeric CPs consisting of TMGMV-J and PaMMV-J, we found that the chimeric TMGMV-J CP, whose residues in the β-sheet domain were replaced by those of PaMMV-J, lost its ability to induce L1a gene-mediated resistance at 30°C. In contrast, the chimeric PaMMV-J CP with the β-sheet domain replaced by TMGMV-J CP was able to induce L1a gene-mediated resistance at 30°C. Furthermore, viral particles were not detected in the leaves inoculated with either chimeric virus. These observations indicated that the amino acids within the β-sheet domain were involved in both the induction of L1a gene-mediated resistance and virion formation. Further analyses using chimeric CPs of TMGMV-J and PMMoV indicated that amino acids within the β-sheet domain alone were not sufficient for the induction of L1a gene-mediated resistance by TMGMV-J CP. These results suggest that multiple regions in Tobamovirus CP are implicated in the induction of L1a gene-mediated resistance. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD. Source

Sugita T.,Miyazaki Agricultural Research Institute | Semi Y.,Miyazaki Agricultural Research Institute | Sawada H.,Kochi Prefectural Agriculture Research Center | Sawada H.,Kochi Agricultural College | And 7 more authors.
Molecular Breeding

To facilitate marker-assisted breeding and genetic analyses of pepper (Capsicum annuum), we developed non-redundant 2- or 3-base simple sequence repeat (SSR) markers from enriched C. annuum genomic libraries and from C. annuum cDNA sequences in public databases. The SSR-enriched libraries were constructed using combinations of three restriction enzymes (AluI, HaeIII, and RsaI) and two biotinylated oligonucleotides [b(GA)15 and b(CA)15]. Ultimately, we obtained 1,736 genomic SSR markers and 1,344 cDNA-derived SSR markers from 6,528 clones and 13,003 sequences, respectively. We mapped 597 markers, including 265 of the newly developed SSR markers, onto a linkage map by using doubled-haploid (DH) lines derived from an intraspecific cross of two pure lines of C. annuum (K9-11 × MZC-180). The map, designated as the KL-DH map, consisted of 12 linkage groups. The map covered a genetic distance of 2,028 cM, and the average distance between markers was less than 4 cM. The frame structure of the KL-DH map was compared with the published standard conserved ortholog set II (COSII) map, which was derived from an interspecific F2 population (C. frutescens × C. annuum), by using tomato (Solanum lycopersicum) chromosomal sequences to bridge the two maps. The intraspecific KL-DH map constructed in this study and the interspecific COSII map were similar in map length and marker distribution, suggesting that the KL-DH map covers nearly the whole genome of C. annuum. © 2013 Springer Science+Business Media Dordrecht. Source

Toda S.,Japan National Agriculture and Food Research Organization | Hirose T.,Kochi Prefectural Agriculture Research Center | Kakiuchi K.,Kochi Prefectural Agriculture Research Center | Kodama H.,Okinawa Prefectural Plant Protection Center | And 2 more authors.
Applied Entomology and Zoology

Scirtothrips dorsalis Hood is a cosmopolitan and polyphagous thrips species. Recently, a novel strain of S. dorsalis attacking capsicum crops was found in Japan. A molecular phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I sequences revealed that the capsicum-associated populations were genetically different from Japanese native strains and were closely related to Southeast Asian populations. We named the capsicum-associated populations "strain C" and the Japanese native ones "strain YT". A total of 10 haplotypes were found in strain C and 26 in strain YT. To differentiate the two strains, we developed a multiplex-PCR method using the ribosomal ITS2 region. © 2013 The Japanese Society of Applied Entomology and Zoology. Source

Shimomoto Y.,Kochi University | Shimomoto Y.,Kochi Prefectural Agriculture Research Center | Sato T.,Japan National Institute of Agrobiological Science | Hojo H.,Kochi Experimental Station | And 5 more authors.
Plant Pathology

In order to develop a method for discrimination of Corynespora cassiicola isolates pathogenic to sweet pepper among Japanese isolates, this study analysed pathogenic variations of 64 Japanese isolates of C. cassiicola on perilla, cucumber, tomato, aubergine and sweet pepper, and their multigene phylogeny. Japanese isolates were divided into seven pathogenicity groups (PG1-PG7). The virulence of isolates in PG1-PG5 was restricted to perilla, cucumber, tomato, aubergine and sweet pepper, respectively. Isolates in PG6 were virulent to sweet pepper, tomato and aubergine. Isolates in PG7 were avirulent to all tested plants. Multigene phylogenetic analysis of the isolates based on β-tubulin, translation elongation factor 1-α, calmodulin and actin genes showed three divergent clusters, MP-A, MP-B and MP-C. These clusters included all isolates in PG1, PG2, PG8 and PG9 (MP-A), PG3 and PG5 (MP-B) and PG4 and PG6 (MP-C). Isolates in PG7 were distributed amongst all clusters. Furthermore, random amplified polymorphic DNA (RAPD) analysis using universal primers, Q17 (5'-GAAGCCCTTG-3') and Q13 (5'-GGAGTGGACA-3'), facilitated discrimination of isolates virulent on sweet pepper amongst isolates in MP-B and MP-C, respectively. Together, a combination of the multigene analysis and the RAPD technique allowed the discrimination of the isolates virulent to sweet pepper. © 2010 The Authors. Plant Pathology © 2010 BSPP. Source

Yasutake D.,Kochi University | Okada E.,Kochi University | Ino A.,Kochi Prefectural Agriculture Research Center | Hosokawa T.,7 52 Marunouchi | And 6 more authors.
Environmental Control in Biology

An open-flow chamber equipped with a multiple CO2-gas analyzing system (MGA) was developed for the continuous measurement of the soil respiration rate in a greenhouse. Two fans attached to the chamber facilitate airflow through it. The air from the inlet and outlet of the chamber is sampled, and then, its CO2-gas concentration is analyzed by the MGA, which consists of an infrared gas analyzer, an air pump, a flow meter, and a programmable data logger. The rate of soil respiration is evaluated based on the difference in CO2 concentration between the inlet and outlet air, and on the air flow rate. The chambers were installed into the ridge and the furrow, and the characteristics of soil respiration were then analyzed. The hourly change in the soil respiration rate was almost constant, and it was higher in the ridge (3.2μmol m-2 s-1) than in the furrow (0.5μmol m-2 s-1), which can be attributed to the small amount of surface soil in the furrow. On the other hand, the soil respiration rate on a greenhouse scale was roughly estimated and compared with the rate of CO2 loss from the greenhouse to the ambient air. The rates were nearly equal when the CO2 concentration in the greenhouse was constant. These results suggest that the soil chamber with the MGA is a useful tool for the dynamic analysis of soil respiration in greenhouses. Source

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