Usami T.,Chiba University |
Kanto T.,Hyogo Prefectural Technology Center for Agriculture |
Inderbitzin P.,University of California at Davis |
Itoh M.,Chiba University |
And 5 more authors.
Journal of General Plant Pathology | Year: 2011
In January 2002, Verticillium wilt of lettuce (Lactuca sativa L.) caused by Verticillium tricorpus occurred in upland paddy fields in Hyogo Prefecture for the first time in Japan. This fungal species was first isolated from lettuce in California, USA. In the present study, the genetic relationships between the American and Japanese isolates of V. tricorpus from lettuce were analyzed to determine whether the pathogen could have migrated to Japan from the USA, the major lettuce-seed supplier for Japan. Nucleotide sequences of the rDNA internal transcribed spacer regions, as well as the genes coding for translation elongation factor 1-alpha and RNA polymerase II were compared among American and Japanese V. tricorpus isolates from lettuce. The Japanese isolates of V. tricorpus were distinct from the American. Random amplified polymorphic DNA analyses also supported this conclusion. These results demonstrated that Verticillium wilt on lettuce caused by V. tricorpus in Japan was not related to the isolates causing the disease in California. © 2010 The Author(s).
Sogo K.,Kagawa Prefectural Agricultural Experiment Station |
Miura K.,Japan National Agriculture and Food Research Organization |
Aizawa M.,Kagawa Prefectural Agricultural Experiment Station |
Watanabe T.,Kagawa Prefectural Agricultural Experiment Station |
Stouthamer R.,University of California at Riverside
Applied Entomology and Zoology | Year: 2014
In agriculture, although it is important to identify species of pest insects, their morphological identification is often difficult. DNA genotyping is useful for identifying morphologically indiscriminable species. Thrips tabaci Lindeman has two reproductive modes (arrhenotoky and thelytoky), which differ in their pesticide resistance, but morphological discrimination is not possible. Studies have established a simple method of discriminating the strains by using their mitochondrial DNA sequences. Previous studies have placed so-called arrhenotokous individuals into a “polyphagous thelytokous clade.” We made the discovery of new arrhenotokous strains that place them in the thelytokous monophyletic group. We show that this polyphagous thelytokous clade is not a monophyletic group. Therefore, the methods currently used to distinguish thelytokous and arrhenotokous individuals need to be updated, and we need to detect another region of DNA that will enable us to discriminate between the two types. © 2014, The Japanese Society of Applied Entomology and Zoology.
Rahman M.Z.,Gifu University |
Uematsu S.,Southern Research Institute |
Kimishima E.,Yokohama Plant Protection Station |
Kanto T.,Hyogo Prefectural Technology Center for Agriculture |
And 5 more authors.
Mycoscience | Year: 2015
New diseases of Easter lily and lettuce were noticed in Japan and the pathogens were identified initially as Phytophthora megasperma and Phytophthora sp., respectively, based on morphological characteristics. We re-examined these isolates using phylogenetical and morphological analysis. In a detailed phylogenetic analysis of all clade members that was based on the sequences of eight genomic regions, Easter lily isolates formed a monophyletic group with high bootstrap support. The unique colony pattern supported this result. In separate analyses of Phytophthora clade 8 based on rRNA gene ITS and the cox1 gene sequences, the lettuce isolates grouped with P. lactucae (described from lettuce in Greece) in the rRNA gene ITS tree but formed a distinct group in the cox1 tree. The sporangia of Japanese lettuce isolates germinated directly, an uncommon feature in clade 8b. These results suggested that the Easter lily and lettuce isolates are novel species that we formally describe as Phytophthora lilii sp. nov. and P. pseudolactucae sp. nov., respectively. Moreover, P. lilii appears to represent a new Phytophthora clade. © 2015 The Mycological Society of Japan. Published by Elsevier B.V. All rights reserved.
Chandra D.,Kagawa University |
Matsui T.,Kagawa University |
Suzuki H.,Kagawa University |
Kosugi Y.,Kagawa University |
And 2 more authors.
International Journal of Vegetable Science | Year: 2010
The quality and storability of iceberg lettuce (Lactuca sativa L.) is dependent on growing and storage conditions, which are not completely known. Lettuce was planted at approximately monthly intervals from Sept. 2006 to Feb. 2007. Crops were harvested at approximately monthly intervals from Nov. 2006 to May 2007 and held in storage at 3 and 137°C. Effects of harvest month and storage condition on storage quality-i.e., changes in textural quality, sugar and organic acid contents-as well as shelf-life in iceberg lettuce were examined. Higher values for puncture force and breaking energy and increased sugar content were found in the cooler than in the warmer months. Lower leaf crispness was recorded after one week of storage with a greater degree at 13°C. Total soluble sugar content declined by about 56% and 32% after one week of storage at 13°C in the outer and inner leaves, respectively. Organic acid content did not show any consistent trend. At the end of the harvest season, shelf-life declined by 40% and 30% during storage at 3 and 13°C, respectively. Results indicate that low temperature during growth and storage could ensure a longer shelf-life along with a higher quality of iceberg lettuce. © Taylor & Francis Group, LLC.
Fujita Y.,Japan National Agriculture and Food Research Organization |
Murakami K.,Kagawa Prefectural Agricultural Experiment Station |
Haraguchi H.,FASMAC Co.
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2012
We compared the performance of three DNA extraction methods using 12 processed wheat foods, e.g. noodles, bread, and confectionery items. Three commercial kits, DNeasy Plant Mini Kit, Genomic-tip 20/G, and GM quicker 3, were each tested in three laboratories. Of the three methods, Genomic-tip 20/G produced the best results for DNA purity testing when applied to castella, and it was generally well-suited to all of the food types tested. However, all of the methods successfully extracted DNA from all the analyzed foods, and the DNA was suitable for PCR amplification using a wheat-specific marker. However, PCR amplification was not reproducible in some of the processed food samples when we applied a DNA marker for cultivar identification, regardless of the method used. The results show that, depending on the type of food being tested, PCR conditions need to be optimized slightly in ordertoidentifyacultivar accurately.
Uragami A.,Japan National Agriculture and Food Research Organization |
Ueno R.,Energy and Environmental Research Center |
Ueno R.,Hokkaido Research Organization |
Yamasaki A.,Japan National Agriculture and Food Research Organization |
And 12 more authors.
Horticulture Journal | Year: 2016
This study analyzes the first large-scale asparagus experiment in Japan to examine the productive differences between male and female plants using the rootstock-planting forcing culture technique. This technique has recently been developed in Japan and uses dug-up rootstocks for one-season harvests during the off-crop season. As larger spears and early sprouting are especially favored in this culture for higher yield, it is important to clarify and evaluate the productive traits of the male and female plants. We conducted collaborative research among eight institutes from Hokkaido to Kyushu to examine plants grown at different cultivation sites. There were two digging-up months and different low-temperature backgrounds. Plant rootstocks sourced from the eight different sites used in the experiment were cultured in an abandoned tunnel in Nagano Prefecture, Japan, in a large area with uniform temperature and high humidity throughout the year, and their white spears were harvested. The results of this study show that the female plants had a significantly higher rootstock weight, weight per spear per plant, and weight per early spear per plant, whereas the male plants had a significantly higher total spear number per plant, early spear number per plant, and significantly fewer days to first harvest. No significant differences were observed in soluble solid contents of roots, total spear weight per plant, or early spear weight per plant. It seems that male plants have a tendency to sprout earlier than female plants in response to reduced accumulated low temperature hours, and also to produce a higher total spear number per rootstock weight and total spear weight per rootstock weight. The ranges of most of the productive traits analyzed in this study completely overlapped between the sexes. However, female plants showed higher variation in weight per spear per plant and weight per early spear per plant. © 2016 The Japanese Society for Horticultural Science (JSHS), All rights reserved.
Kurose D.,Japan National Institute for Agro - Environmental Sciences |
Misawa T.,Hokkaido Research Organization |
Suzui T.,Japan National Institute of Agrobiological Science |
Ichikawa K.,Yamanashi Prefectural Agritechnology Center |
And 6 more authors.
Journal of General Plant Pathology | Year: 2015
Most of the many Stemphylium species on record as plant pathogens in Japan have been identified by morphology. Using molecular phylogenetic analysis of four loci (rDNA-ITS, EF-1α, GPD, and vmaA-vpsA) combined, we re-examined the taxonomy of 31 Stemphylium strains that had been identified morphologically before or after their deposit in the NIAS Genebank, Japan. In the present study, these Japanese strains were separated into three groups (Groups A, C, and E). Sixteen Japanese strains formed a new subgroup (designated Subgroup C2) that contained no type or ex-type strains of existing species. Four of the strains had been identified correctly, whereas the other 27 strains appear to have been misidentified based on our phylogenetic analysis. We examined the conidial morphology of four representative misidentified strains selected from each clade. While the morphological characteristics of a strain isolated from Welsh onion resembles those of the S. vesicarium type, this strain belongs to Subgroup C2 rather than Subgroup C1 and, therefore, could not be identified at the species level. Conversely, three pathogenic strains isolated from aster, asparagus, and Chinese chive were re-identified based on our combined morphological and phylogenetic data. We propose the scientific names of the aster leaf spot pathogen as S. lycopersici, and the asparagus Stemphylium leaf spot and Chinese chive brown leaf blight pathogens as S. herbarum. © 2015, The Phytopathological Society of Japan and Springer Japan.