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<p>(A) Graphical genotype of chromosome 6 of SHA422-1.1 (<i>APO1</i> near-isogenic line) and SHA422-1.3. The thickest arrow represents the open reading frame of <i>APO1</i>; narrower arrows represent other... more
<p>(A) Graphical genotype of chromosome 6 of SHA422-1.1 (<i>APO1</i> near-isogenic line) and SHA422-1.3. The thickest arrow represents the open reading frame of <i>APO1</i>; narrower arrows represent other predicted genes. 1.1, SHA422-1.1; 1.3, SHA422-1.3. Modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123308#pone.0123308.ref020" target="_blank">20</a>]. (B, C) Effects of the Habataki-type <i>APO1</i> gene on (B) grain yield and (C) the number of primary rachis branches. Values are mean ± SD (<i>n</i> = 36). NF, non-filtered air (converted values); O<sub>3</sub>, elevated ozone. Bars topped by the same letters are not significantly different (Tukey’s HSD test, <i>P</i><0.05).</p
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Research Interests: Plant Biology, Plant cell physiology, Apoptosis, Signal Transduction, Phylogeny, and 14 morePlant diseases, Mutation, Programmed cell death, Arabidopsis, Phenotype, Immune system, Plant cell, Amino Acid Sequence, Base Sequence, Hypersensitive Response, Salicylic Acid, PLANT PROTEINS, Biochemistry and cell biology, and Molecular Sequence Data
Research Interests: Carbon Dioxide, Plant Biology, Plant cell physiology, Membrane Proteins, Arabidopsis thaliana, and 15 morePhylogeny, Mutation, Stomata, Programmed cell death, Arabidopsis, Hydrogen Peroxide, Ozone, Low Temperature, Genome sequence, Salicylic Acid, Sulfur Dioxide, Biochemistry and cell biology, Jasmonic Acid, Stomatal Conductance, and high light
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Dehydroascorbate reductase (DHAR) is a key component of the ascorbate recycling system. Three functional DHAR genes are encoded in the Arabidopsis genome. Ozone exposure increased the expression of the cytosolic DHAR (cytDHAR) gene alone.... more
Dehydroascorbate reductase (DHAR) is a key component of the ascorbate recycling system. Three functional DHAR genes are encoded in the Arabidopsis genome. Ozone exposure increased the expression of the cytosolic DHAR (cytDHAR) gene alone. We characterized an Arabidopsis mutant with a deficient cytDHAR. The mutant completely lacked cytDHAR activity and was highly ozone sensitive. The amounts of total ascorbate and glutathione were similar in both lines, but the amount of apoplastic ascorbate in the mutant was 61.5% lower. These results indicate that the apoplastic ascorbate, which is generated through the reduction of DHA by cytDHAR, is important for ozone tolerance.
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Light-dependent transcriptional activation of the photolyase gene imparts UVB tolerance to a plant. In the present study, the cucumber CPD photolyase gene (CsPHR) was isolated from a genomic DNA library and its genomic structure was... more
Light-dependent transcriptional activation of the photolyase gene imparts UVB tolerance to a plant. In the present study, the cucumber CPD photolyase gene (CsPHR) was isolated from a genomic DNA library and its genomic structure was scrutinized. As a result, putative light-responsive cis-acting elements were found in the CsPHR promoter.
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Research Interests: Genetics, RNA interference, Stress response, Plant Growth Regulators, Plant growth, and 15 morePlant Molecular Genetics and Functional Genomics, Glucuronidase, Arabidopsis, Abscisic Acid, Phenotype, Genotype, Ozone, Onion, Environmental Stress, Amino Acid Sequence, Salicylic Acid, Fusion Protein, Epidermal Stem Cells, Molecular Sequence Data, and reverse transcriptase polymerase chain reaction
Transgenic tobacco plants were generated carrying a rice homeobox gene, OSH1, controlled by the promoter of a gene encoding a tobacco pathogenesis-related protein (PR1a). These lines were morphologically abnormal, with wrinkled and/or... more
Transgenic tobacco plants were generated carrying a rice homeobox gene, OSH1, controlled by the promoter of a gene encoding a tobacco pathogenesis-related protein (PR1a). These lines were morphologically abnormal, with wrinkled and/or lobed leaves. Histological analysis of shoot apex primordia indicates arrest of lateral leaf blade expansion, often resulting in asymmetric and anisotrophic growth of leaf blades. Other notable abnormalities included abnormal or arrested development of leaf lateral veins. Interestingly, OHS1 expression was undetectable in mature leaves with the aberrant morphological features. Thus, OSH1 expression in mature leaves is not necessary for abnormal leaf development. Northern blot and in situ hybridization analyses indicate that PR1a-OSH1 is expressed only in the shoot apical meristem and in very young leaf primordia. Therefore, the aberrant morphological features are an indirect consequence of ectopic OSH1 gene expression. The only abnormality observed in tissues expressing the transgene was periclinal (rather than anticlinal) division in mesophyll cells during leaf blade initiation. This generates thicker leaf blades and disrupts the mesophyll cell layers, from which vascular tissues differentiate. The OSH1 product appears to affect the mechanism controlling the orientation of the plane of cell division, resulting in abnormal periclinal division of mesophyll cell, which in turn results in the gross morphological abnormalities observed in the transgenic lines.
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Research Interests: Plant Biology, Abiotic Stress, Stress response, Plant, Cell Death, and 15 moreBiotic Stress, Arabidopsis, Freezing Tolerance, PLANT DEFENSE, Molecular cloning, Low Temperature, Physiological Stress Markers, Amino Acid Sequence, Protein Binding, Freezing, Salicylic Acid, Gene expression profiling, Molecular Sequence Data, Signaling pathway, and Stress Physiological
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Plants in the field are subjected to numerous environmental stresses. Lengthy continuation of such environmental stresses or a rapid increase in their intensity is harmful to vegetation. Assessments of the phytotoxicity of various... more
Plants in the field are subjected to numerous environmental stresses. Lengthy continuation of such environmental stresses or a rapid increase in their intensity is harmful to vegetation. Assessments of the phytotoxicity of various stresses have been performed in many countries, although they have largely been based on estimates of leaf injury. We developed a novel method of detecting plant stresses that is more sensitive and specific than those previously available. This method is based on the detection of mRNA expression changes in 205 ozone-responsive Arabidopsis expressed sequence tags (ESTs) by cDNA macroarray analysis. By using this method, we illustrated shifts in gene expression in response to stressors such as drought, salinity, UV-B, low temperature, high temperature, and acid rain, as distinct from those in response to ozone. We also made a mini-scale macroarray with 12 ESTs for diagnosis of the above environmental stresses in plants. These results illustrate the potential of our cDNA macroarray for diagnosis of various stresses in plants.
Research Interests: Air pollution, Environmental Pollution, Acid Rain, Gene expression, Multidisciplinary, and 12 moreArabidopsis thaliana, Expressed Sequence Tags, High Temperature, Arabidopsis, mRna expression levels, Ozone, Environmental Stress, Toxicogenetics, Low Temperature, Sensitivity and Specificity, Gene expression profiling, and Ultraviolet Rays
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We reported isolation and characterization of a homeobox gene from tobacco, NTH23. The homeodomain structure of NTH23 was highly homologous to the same regions of class 2 genes of the KN1-type homeobox (sharing more than 85% amino acid... more
We reported isolation and characterization of a homeobox gene from tobacco, NTH23. The homeodomain structure of NTH23 was highly homologous to the same regions of class 2 genes of the KN1-type homeobox (sharing more than 85% amino acid identity), but was less similar to class 1 genes of KN1-type. RNA gel blot analysis revealed that NTH23 was expressed in all organs we tested although the gene is primarily expressed in young leaves. To determine more precisely the spatial expression pattern of NTH23 in tobacco, a chimeric NTH23::GUS fusion gene was introduced into tobacco. The signal of GUS activity was observed at the basal part of leaf blade primordia in the NTH23::GUS transgenic tobacco plants. This observation suggests the possibility that NTH23 may be important for the lateral growth of leaf blades.
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A rice homeobox gene, OSH1, contains two functionally independent promoters which generate a larger transcript and a smaller transcript. In Arabidopsis, each promoter can drive the expression of a reporter gene in a different manner,... more
A rice homeobox gene, OSH1, contains two functionally independent promoters which generate a larger transcript and a smaller transcript. In Arabidopsis, each promoter can drive the expression of a reporter gene in a different manner, indicating that the expression of different sized transcripts is independently regulated by each promoter. Over-expression of the larger transcript in transformed plants caused altered morphologies (Matsuoka et al., Plant Cell, 1993, 5, 1039-1048); in contrast, over-expression of the smaller transcript did not cause any morphological changes. The results suggest that the product of the smaller transcript fails to alter the expression of its target gene(s) in the transformants, while that of the larger transcript is capable of altering the expression of its target gene(s).
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Monitoring of transgenic plants in the field is important, but risk assessment has entailed laborious use of invisible marker genes. Here, we assessed three easily visible marker transgenes--green fluorescent protein (GFP), R, and... more
Monitoring of transgenic plants in the field is important, but risk assessment has entailed laborious use of invisible marker genes. Here, we assessed three easily visible marker transgenes--green fluorescent protein (GFP), R, and Nicotiana tabacum homeobox (NTH) 15 genes--for their potential use as marker genes for monitoring genetically modified plants. Transgenic Arabidopsis thaliana plants for each of these genes were visibly distinguished from wild-type plants. We determined the germination rate, 3-week fresh weight, time to first flowering, and seed weight of the transgenic plants to evaluate whether the expression of these marker genes affected the growth of the host. Introduction of GFP gene had no effect on the evaluated parameters, and we then used the GFP gene as a marker to assess the outcrossing frequency between transgenic and two Arabidopsis species. Our results showed that the hybridization frequency between transgenic plants and Arabidopsis thaliana was 0.24%, and b...
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To understand better the plant response to ozone, we isolated and characterized an ozone-sensitive (ozs1) mutant strain from a set of T-DNA-tagged Arabidopsis thaliana ecotype Columbia. The mutant plants show enhanced sensitivity to... more
To understand better the plant response to ozone, we isolated and characterized an ozone-sensitive (ozs1) mutant strain from a set of T-DNA-tagged Arabidopsis thaliana ecotype Columbia. The mutant plants show enhanced sensitivity to ozone, desiccation and sulfur dioxide, but have normal sensitivity to hydrogen peroxide, low temperature and high light levels. The T-DNA was inserted at a single locus which is linked to ozone sensitivity. Identification of the genomic sequences flanking the T-DNA insertion revealed disruption of a gene encoding a transporter-like protein of the tellurite resistance/C4-dicarboxylate transporter family. Plants with either of two different T-DNA insertions in this gene were also sensitive to ozone, and these plants failed to complement ozs1. Transpiration levels, stomatal conductance levels and the size of stomatal apertures were greater in ozs1
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Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investi-gated the responses to ozone of two rice (Oryza Sativa... more
Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investi-gated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Haba-taki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substi-tution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and de...
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Phyton (Horn, Austria) 45 (4): (109)-(1/5). Ozone, a major photochemical oxidant, induces leaf injury. Salicylic acid (SA) is a kind of plant hormone and an important regulator of plant resistance to pathogens. In ozone-exposed plants, SA... more
Phyton (Horn, Austria) 45 (4): (109)-(1/5). Ozone, a major photochemical oxidant, induces leaf injury. Salicylic acid (SA) is a kind of plant hormone and an important regulator of plant resistance to pathogens. In ozone-exposed plants, SA participates in both the formation of leaf injury and the defense response. In pathogen-infected plants, SA is synthesized via two pathways involving phenylalanine or isochorismate. Biosynthesis of SA in ozone-fumigated plants had not been well defined, so we examined it in tobacco and Arabidopsis. Salicylic acid accumulated in tobacco exposed to 0.2 ppm ozone for 6 h. At the same time, phenylalanine ammonia-lyase (PAL) activity, its mRNA level, and the level of chorismate mutase (CM) transcripts increased remarkably, whereas isochorismate synthase (ICS) activity did not increase. These results may suggest that ozone-exposed tobacco synthesized SA via the phenylalanine pathway. Salicylic acid levels also increased in ozone-exposed Arabidopsis, but ...
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Nymphonella tapetis (Pycnogonida, Ascorhynchidae) is an endoparasitic sea spider affecting bivalves. Recently, sea spiders have been found on a massive scale in the commercially important Manila clams (Veneridae, Ruditapes philippinarum)... more
Nymphonella tapetis (Pycnogonida, Ascorhynchidae) is an endoparasitic sea spider affecting bivalves. Recently, sea spiders have been found on a massive scale in the commercially important Manila clams (Veneridae, Ruditapes philippinarum) in Japan (Tokyo Bay). Simultaneously, mass mortality has occurred in this area. Local fishers assumed that this mass mortality was caused by the parasitic sea spider, despite the effect of the parasite and parasite intensity on the host being unknown. To evaluate the susceptibility of the Manila clam to sea spider infestation and the impact on mortality levels, we established six treatments at different infection intensities (density of newly hatched larvae of sea spiders) over a 6-month long laboratory experiment. We monitored mortality and three susceptibility indices (clearance rate, sand-burrowing speed and adductor muscle strength) under sufficient food conditions. Parasitization by sea spider affected clearance rate and sand-burrowing speed. T...
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It is becoming clear that ozone affects not only grain yield but also grain quality in rice. However, the biochemical mechanisms responsible for ozone-induced changes in appearance quality or components are poorly understood. We analyzed... more
It is becoming clear that ozone affects not only grain yield but also grain quality in rice. However, the biochemical mechanisms responsible for ozone-induced changes in appearance quality or components are poorly understood. We analyzed appearance quality and starch composition in the rice cultivars "Koshihikari" (japonica) and "Kasalath" (indica) grown under elevated ozone conditions. Elevated ozone significantly increased the proportion of immature (mainly chalky) kernels in "Koshihikari" but not in "Kasalath". Scanning electron microscopy of transverse sections of kernels showed that endosperm starch granules of "Koshihikari" ripened under elevated ozone were loosely packed with large spaces and contained irregular rounded granules. Amylose content was increased in "Koshihikari" kernels with ozone exposure, but was unchanged in "Kasalath" kernels. Distribution analysis of amylopectin chain length showed that o...
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A sudden outbreak of the parasitic sea spider Nymphonella tapetis accompanied by mass mortality of the Manila (asari) clam Ruditapes philippinarum was observed in Japan in 2007. It was unknown why dead and dying clams were found on the... more
A sudden outbreak of the parasitic sea spider Nymphonella tapetis accompanied by mass mortality of the Manila (asari) clam Ruditapes philippinarum was observed in Japan in 2007. It was unknown why dead and dying clams were found on the sand surface. In our laboratory experiment, in which sea spiders were artificially parasitised to host clams, unburied clams were significantly increased, suggesting that sea spider parasitism can change the burial mode of clams. We compared parasite loads, somatic condition and reburial activity of Manila clams among three burial groups (fully buried, partly buried and unburied) collected from the field. Unburied and partly buried clams had 30% lower soft body weight and 60% lower adductor strength as compared to the fully buried clams. Parasite prevalence and the mean infection intensity were greater in unburied and partly buried clams than in fully buried clams. Reburial depth was smaller in unburied and partly buried clams than in fully buried clams under laboratory conditions. Approximately 30% of the unburied and partly buried clams died during 30 days, whereas fully buried clams suffered no mortality. These results indicate that sea spider parasitism can reduce the burial depth and somatic condition of host clams, and eventually cause clam mortality on the sand.
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Research Interests: Biology, Medicine, Molecular Mechanics, Biological Sciences, Antioxidants, and 15 morePlant Physiology, Reactive Oxygen Species, Chlorophyll, Selenium, Brassicaceae, Plant, Organoselenium Compounds, Sulfur, Phenols, Ascorbic Acid, Gas Chromatography/mass Spectrometry, Salicylic Acid, Gene expression profiling, Plant Leaves, and Lawrence Berkeley Laboratory
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Research Interests: Genetics, Gene Flow, Plant Biology, Biology, Population Dynamics, and 15 moreEnvironmental Monitoring, Japan, PCR, Environmental Risk, Maize, Herbicide Resistance, Population Density, multiplex PCR, Genetically Modified, Natural Environment, Brassica Napus, Food Sciences, Environmental, Food control, and Oilseed rape
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We aimed to reveal the dispersal and gene flow of the local wild boar (Sus scrofa) population and find their genetic boundary in Fukushima Prefecture. After the nuclear incident in 2011, the land was considered a difficult-to-return zone,... more
We aimed to reveal the dispersal and gene flow of the local wild boar (Sus scrofa) population and find their genetic boundary in Fukushima Prefecture. After the nuclear incident in 2011, the land was considered a difficult-to-return zone, and the increase in the number of wild boars was pronounced. To provide an effective management strategy for the wild boar population, we used multiplexed inter-simple sequence repeat genotyping by sequencing (MIG-seq) and clarified the genetic structure of wild boars. We obtained 328 single-nucleotide polymorphisms from 179 samples. STRUCTURE analysis showed that the most likely number of population cluster was K = 2. Molecular analysis of variance showed significant genetic differences between groups of wild boars inhabiting in the east and west across the Abukuma River. The migration rate from the eastern population to the western population is higher than in the reverse case based on BayesAss analysis. Our study indicates that both the Abukuma ...
