Toru Matoh

Publications (15)47.29 Total impact

• Article: Distribution and Partitioning of Newly Taken-up Boron in Sunflower

  Toru Matoh, Kumiko Ochiai
  [show abstract] [hide abstract]
  ABSTRACT: Distribution and partitioning of newly acquired boron (B) in a mature sunflower (Helianthus annuus L., cv. 3101) plant was investigated. In leaf blades of sunflower plants grown under 0.93, 2.8, and 9.3mmol Bm−3, the level of cell-wall-bound B was rather uniform, irrespective of leaf position and B concentration. Boron concentration gradients among leaf positions were produced mainly by different levels of water-soluble B. To determine the distribution of newly taken-up B in plant parts, 10B-labeled boric acid at a concentration of 2.8mmol Bm−3 was applied. The majority of newly acquired B was delivered to the younger leaves, however, approximately one-fourth of the B in the top and second leaves was the older B which was taken up before the 6d treatment period. In the root tissues, two-fifth of the water-soluble B was new B taken up in the last 6d, however, within 6h of the application new B contributed to approximately 80% of the xylem sap B, suggesting that newly taken-up B is preferentially transported to the shoots. When B was withdrawn from the culture solution, the B concentration per leaf area of the lower leaves decreased slightly over 9d. However, there was an abrupt decrease in the younger leaves, even when taking into account the rapid expansion of the leaf blade, suggesting that B moves more rapidly from the younger leaves than from the older leaves
  Plant and Soil 04/2012; 278(1):351-360. · 2.73 Impact Factor
• Article: Characterization of Arabidopsis CTP:3-deoxy-D-manno-2-octulosonate cytidylyltransferase (CMP-KDO synthetase), the enzyme that activates KDO during rhamnogalacturonan II biosynthesis.

  Masaru Kobayashi, Nagisa Kouzu, Akina Inami, Kiminori Toyooka, Yuki Konishi, Ken Matsuoka, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: In plant cells, boron (B) occurs predominantly as a borate ester associated with rhamnogalacturonan II (RG-II), but the function of this B-RG-II complex has yet to be investigated. 3-Deoxy-D-manno-2-octulosonic acid (KDO) is a specific component monosaccharide of RG-II. Mutant plants defective in KDO biosynthesis are expected to have altered RG-II structure, and would be useful for studying the physiological function of the B-RG-II complex. Here, we characterized Arabidopsis CTP:KDO cytidylyltransferase (CMP-KDO synthetase; CKS), the enzyme activating KDO as a nucleotide sugar prior to its incorporation into RG-II. Our analyses localized the Arabidopsis CKS protein to mitochondria. The Arabidopsis CKS gene occurs as a single-copy gene in the genome, and we could not obtain cks null mutants from T-DNA insertion lines. Analysis using +/cks heterozygotes in the quartet1 background demonstrated that the cks mutation rendered pollen infertile through the inhibition of pollen tube elongation. These results suggest that KDO is an indispensable component of RG-II, and that the complete B-RG-II complex is essential for the cell wall integrity of rapidly growing tissues.
  Plant and Cell Physiology 09/2011; 52(10):1832-43. · 4.70 Impact Factor
• Article: Suppression of a NAC-like transcription factor gene improves boron-toxicity tolerance in rice.

  Kumiko Ochiai, Akifumi Shimizu, Yutaka Okumoto, Toru Fujiwara, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: We identified a gene responsible for tolerance to boron (B) toxicity in rice (Oryza sativa), named BORON EXCESS TOLERANT1. Using recombinant inbred lines derived from the B-toxicity-sensitive indica-ecotype cultivar IR36 and the tolerant japonica-ecotype cultivar Nekken 1, the region responsible for tolerance to B toxicity was narrowed to 49 kb on chromosome 4. Eight genes are annotated in this region. The DNA sequence in this region was compared between the B-toxicity-sensitive japonica cultivar Wataribune and the B-toxicity-tolerant japonica cultivar Nipponbare by eco-TILLING analysis and revealed a one-base insertion mutation in the open reading frame sequence of the gene Os04g0477300. The gene encodes a NAC (NAM, ATAF, and CUC)-like transcription factor and the function of the transcript is abolished in B-toxicity-tolerant cultivars. Transgenic plants in which the expression of Os04g0477300 is abolished by RNA interference gain tolerance to B toxicity.
  Plant physiology 05/2011; 156(3):1457-63. · 6.53 Impact Factor
• Article: Boron nutrition of cultured tobacco BY-2 cells. VI. Calcium is involved in early responses to boron deprivation.

  Taichi Koshiba, Masaru Kobayashi, Atsushi Ishihara, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: Boron (B) deprivation induces various responses in plant cells, some of which can be observed very early. However, it has been unknown what kind of signal is generated by the stress. We found that B deprivation induced the expression of stress-responsive genes within 1 h in suspension-cultured tobacco BY-2 cells. The induction was largely suppressed by withholding medium Ca(2+) or by adding a Ca(2+) channel blocker. Analysis using aequorin-expressing cells showed that B-deprived cells took up more Ca(2+) than control cells. These results suggest that Ca(2+) influx plays a role in B deprivation stress signaling.
  Plant and Cell Physiology 12/2009; 51(2):323-7. · 4.70 Impact Factor
• Article: Boron deficiency: how does the defect in cell wall damage the cells?

  Taichi Koshiba, Masaru Kobayashi, Toru Matoh
  Plant signaling & behavior 06/2009; 4(6):557-8.
• Article: Plant nutrition--roots of life for fundamental biology and better crop production.

  Toru Fujiwara, Toru Matoh
  Plant and Cell Physiology 02/2009; 50(1):2-4. · 4.70 Impact Factor
• Source

  Available from: PubMed Central

  Article: Boron nutrition of tobacco BY-2 cells. V. oxidative damage is the major cause of cell death induced by boron deprivation.

  Taichi Koshiba, Masaru Kobayashi, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: Boron (B) is an essential micronutrient for vascular plants. However, it remains unclear how B deficiency leads to various metabolic disorders and cell death. To understand this mechanism, we analyzed the physiological changes in suspension-cultured tobacco (Nicotiana tabacum) BY-2 cells upon B deprivation. When 3-day-old cells were transferred to B-free medium, cell death was detectable as early as 12 h after treatment. The B-deprived cells accumulated more reactive oxygen species and lipid peroxides than control cells, and showed a slight but significant decrease in the cellular ascorbate pool. Supplementing the media with lipophilic antioxidants effectively suppressed the death of B-deprived cells, suggesting that the oxidative damage is the immediate and major cause of cell death under B deficiency. Dead cells in B-free culture exhibited a characteristic morphology with a shrunken cytoplasm, which is often seen in cells undergoing programmed cell death (PCD). However, they did not display other hallmarks of PCD such as internucleosomal DNA fragmentation, decreased ascorbate peroxidase expression and protection from death by cycloheximide. These results suggest that the death of tobacco cells induced by B deprivation is not likely to be a typical PCD.
  Plant and Cell Physiology 01/2009; 50(1):26-36. · 4.70 Impact Factor
• Article: Boron nutrition of cultured tobacco BY-2 cells. IV. Genes induced under low boron supply.

  Masaru Kobayashi, Takashi Mutoh, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: Genes whose expression was up-regulated in low boron (B)-acclimated tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yellow 2) cells, which had been selected under a low supply of B, were screened by the cDNA differential subtraction method. Thirteen genes were identified, including early salicylate-inducible glucosyltransferase, glutamine synthetase, glutathione S-transferase, and a pathogenesis-related protein, which might constitute a rescue system for oxidative damage. This indicates that B deficiency might impose cellular redox imbalance on the cells. Two of the 13 genes were induced within 30 min of B removal in the parent cells, indicating fast signal transfer from the cell walls to the cytoplasm.
  Journal of Experimental Botany 07/2004; 55(401):1441-3. · 5.36 Impact Factor
• Article: Alleviation of salinity damage to rice plants by the use of polyethylene glycols (PEGs) through reduction of Na+ trasport to shoots

  Kumiko Ochiai, Toru Matoh
  Soil Science and Plant Nutrition 02/2004; 50(1):129-133. · 1.02 Impact Factor
• Article: Arabidopsis 3-deoxy-D-manno-oct-2-ulosonate-8-phosphate synthase: cDNA cloning and expression analyses.

  Keiichi Matsuura, Isao Miyagawa, Masaru Kobayashi, Daisaku Ohta, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: The molecular characterization of two isoforms of 3-deoxy-d-manno-oct-2-ulosonate (KDO) -8-phosphate synthase (AtkdsA1 and AtkdsA2) from Arabidopsis is reported here. First, by isolating a full-length cDNA for AtkdsA1, it was confirmed that the deduced primary structures of AtkdsA1 and AtkdsA2 proteins were 93% identical. Functional expression and purification studies demonstrated the efficient catalytic activity of the AtkdsA1 enzyme to produce KDO-8-phosphate from phosphoenolpyruvate and d-arabinose-5-phosphate. RT-PCR and RNA-gel blot analysis revealed different expression profiles for both genes; the AtkdsA1 gene was predominantly expressed in the shoots, while the AtkdsA2 transcript accumulated to a higher level in the roots, implicating differential roles of these isoforms in planta.
  Journal of Experimental Botany 08/2003; 54(388):1785-7. · 5.36 Impact Factor
• Article: Purification and cDNA cloning of UDP-D-glucuronate carboxy-lyase (UDP-D-xylose synthase) from pea seedlings.

  Masaru Kobayashi, Hironobu Nakagawa, Izumi Suda, Isao Miyagawa, Toru Matoh
  [show abstract] [hide abstract]
  ABSTRACT: Uridine diphospho-D-glucuronate carboxy-lyase (UDP-D-xylose synthase; EC 4.1.1.35), which catalyzes the conversion of UDP-D-glucuronate to UDP-D-xylose, was purified to apparent homogenity from pea (Pisum sativum L.) seedlings. The pH optimum for enzyme activity was around 5-6, and the activity was not affected by exogeneously supplied NAD+ and NADH. The purified enzyme had a molecular weight of 250 kDa and consisted of 42 kDa polypeptides. Based on the amino acid sequence, a probe (400 bp) was prepared with degenerate primers by a reverse transcriptase-PCR. Using this probe, a clone encoding 346 amino acid residues was screened from a pea cDNA library. The recombinant protein expressed in Escherichia coli catalyzed conversion of UDP-D-glucuronate to UDP-D-xylose, confirming that the isolated clone encoded UDP-D-glucuronate carboxy-lyase.
  Plant and Cell Physiology 12/2002; 43(11):1259-65. · 4.70 Impact Factor
• Article: Characterization of the Na+ delivery from roots to shoots in rice under saline stress: Excessive salt enhances apoplastic transport in rice plants

  Kumiko Ochiai, Toru Matoh
  Soil Science and Plant Nutrition 06/2002; 48(3):371-378. · 1.02 Impact Factor
• Article: Boron and calcium, essential inorganic constituents of pectic polysaccharides in higher plant cell walls

  Toru Matoh, Masaru Kobayashi
  [show abstract] [hide abstract]
  ABSTRACT: Among 16 essential elements of higher plants, Ca2+ and B have been termed as apoplastic elements. This is mainly because of their localization in cell walls, however, it has turned to be highly likely that these two elements significantly contribute to maintain the integrity of cell walls through binding to pectic polysaccharides. Boron in cell walls exclusively forms a complex with rhamnogalacturonan II (RG-II), and the B-RG-II complex is ubiquitous in higher plants. Analysis of the structure of the B-RG-II complex revealed that the complex contains two molecules boric acid, two molecules Ca2+ and two chains of monomeric RG-II. This result indicates that pectic chains are cross-linked covalently with boric acid at their RG-II regions. The complex was reconstitutedin vitro only by mixing monomeric RG-II and boric acid, however, the complex decomposed spontaneously unless Ca2+ was supplemented. Furthermore, the native complex decomposed when it was incubated withtrans-1,2-diaminocyclohexane-N, N, N′, N′-tetraacetic acid (CDTA) which chelates Ca2+. When radish root cell walls were washed with a buffered 1.5% (w/v) sodium dodesyl sulfate (SDS) solution (pH 6.5), 96%, 13% and 6% of Ca2+, B and pectic polysaccharides of the cell walls, respectively, were released and the cell wall swelled twice. Subsequent extraction with 50 mM CDTA (pH 6.5) of the SDS-washed cell walls further released 4%, 80% and 61% of Ca2+, B and pectic polysaccharides, respectively. Pectinase hydrolysis of the SDS-treated cell walls yielded a B-RG-II complex and almost all the remaining Ca2+ was recovered in the complex. This result suggests that cell-wall bound Ca2+ is divided into at least two fractions, one anchors the CDTA-soluble pectic polysaccharides into cell walls together with B, and the other may control the properties of the pectic gel. These studies demonstrate that B functions to retain CDTA-soluble pectic polysaccharides in cell walls through its binding to the RG-II regions in collaboration with Ca2+.
  Journal of Plant Research 02/1998; 111(1):179-190. · 1.75 Impact Factor
• Source

  Available from: oxfordjournals.org

  Article: Ubiquity of a Borate-Rhamnogalacturonan II Complex in the Cell Walls of Higher Plants

  Toru Matoh, Sayaka Kawaguchi, Masaru Kobayashi
  [show abstract] [hide abstract]
  ABSTRACT: The presence of a borate-rhamnogalacturonan II (RGII) complex [Kobayashi et al. (1996) Plant Physiol . 110: 1017] was examined in cell walls of 24 species from higher plants. We studied two species in Brassicaceae, three in Cucurbitaceae, four in Leguminosae, two in Apiaceae, two in Chenopodiaceae, two in Solanaceae, two in Asteraceae, one in Liliaceae, one in Araeae, two in Amaryllidaceae and three in Gramineae. In all the species examined, cell-wall boron was judged to be associated with RG-II. Moreover, in 15 species it seemed likely that RG-II might be the exclusive carrier of boron in the cell wall.
• Article: Immunocytochemistry of Rhamnogalacturonan II in Cell Walls of Higher Plants

  Toru Matoh, Miki Takasaki, Keiji Takabe, Masaru Kobayashi
  [show abstract] [hide abstract]
  ABSTRACT: A polyclonal antibody against a borate-RG-II complex is raised in rabbits. The antibody recognized RG-II exclusively in cell wall polysaccharides. Immunocytochemical studies demonstrated that the epitope is ubiquitous in cell walls of all the cells in radish and rice roots, cultured tobacco cells, red clover root nodules, and lily growing pollen tubes. The label was denser in proximal to plasma membrane, and not detected in middle lamella, suggesting that borate may cross-link newly secreted pectic polysaccharides at the membrane-cell wall interface.