Yukihiro Sugimoto

Kobe University, Kōbe, Hyōgo, Japan

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Publications (96)209.12 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Bioconversion of GR24, the most widely used synthetic strigolactone (SL), by hydroponically grown sorghum (Sorghum bicolor) and biological activities of hydroxylated GR24 stereoisomers were studied. Analysis of extracts and exudates of sorghum roots previously fed with a racemic and diastereomeric mixture of GR24, using liquid chromatography-tandem mass spectrometry with multiple reaction monitoring (MRM), confirmed uptake of GR24 and suggested its conversion to mono-hydroxylated products. Two major GR24 metabolites, 7-hydroxy-GR24 and 8-hydroxy-GR24, were identified in the root extracts and exudates by direct comparison of chromatographic behavior with a series of synthetic mono-hydroxylated GR24 analogues. Separate feeding experiments with each of the GR24 stereoisomers revealed that the hydroxylated products were derived from 2'-epi-GR24, an evidence of sterical recognition of the GR24 molecule by sorghum. Trans-4-hydroxy-GR24 isomers derived from all GR24 stereoisomers were detected in the exudates as minor metabolites. The synthetic hydroxy-GR24 isomers induced germination of Striga hermonthica in decreasing order of C-8>C-7>C-6>C-5>C-4. In contrast the stereoisomers having the same configuration of orobanchol, irrespective of position of hydroxylation, induced germination of Striga gesnerioides. The results confirm previous reports on structural requirements of SLs and ascribe a critical role to hydroxylation, but not to the position of the hydroxyl group in the AB part of the molecule, in induction of S. gesnerioides seed germination. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Bioorganic & medicinal chemistry 08/2015; 23(18). DOI:10.1016/j.bmc.2015.08.003 · 2.79 Impact Factor
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    ABSTRACT: Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, as indicators of host roots within reach of the parasite's radicles. This unique germination process was focused on to identify metabolic pathways required for germination, and to design a selective control strategy. A metabolomic analysis of germinating seeds of clover broomrape, Orobanche minor, was conducted to identify its distinctive metabolites. Consequently, a galactosyl-sucrose trisaccharide, planteose (α-d-galactopyranosyl-(1→6)-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside), was identified as a metabolite that decreased promptly after reception of the germination stimulant. To investigate the importance of planteose metabolism, the effects of several glycosidase inhibitors were examined, and nojirimycin bisulfite (NJ) was found to alter the sugar metabolism and to selectively inhibit the germination of O. minor. Planteose consumption was similar in NJ-treated seeds and non-treated germinating seeds; however, NJ-treated seeds showed lower consumption of sucrose, a possible intermediate of planteose metabolism, resulting in significantly less glucose and fructose. This inhibitory effect was recovered by adding glucose. These results suggest that planteose is a storage carbohydrate required for early stage of germination of O. minor, and NJ inhibits germination by blocking the supply of essential glucose from planteose and sucrose. Additionally, NJ selectively inhibited radicle elongation of germinated seeds of Orobanchaceae plants (Striga hermonthica and Phtheirospermum japonicum). Thus, NJ will be a promising tool to develop specific herbicides to the parasites, especially broomrapes, and to improve our understanding of the molecular mechanisms of this unique germination. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.
    Journal of Experimental Botany 03/2015; 66(11). DOI:10.1093/jxb/erv116 · 5.53 Impact Factor
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    ABSTRACT: Abiotic stresses cause serious damage to plants; therefore, plants undergo a complicated stress response through signal transduction originating from environmental stimuli. Here we show that a subset of short-chain leaf volatiles with an α, β-unsaturated carbonyl bond in their structure (reactive short-chain leaf volatiles, RSLVs) like (E)-2-hexenal and (E)-2-butenal can act as signal chemicals that strongly induce the gene expression of abiotic-related transcription factors, such as heat stress-related transcription factors (HSFA2, MBF1c) and other abiotic stress-related transcription factors (DREB2A, ZATs). RSLV-induced expression of HSFA2 and MBF1c was eliminated in HSFA1s-, known as heat stress response master regulators, knockout mutant, whereas those of DREB2A and ZATs were not, suggesting that the RSLV signaling pathway is composed of HSFA1-dependent and -independent pathways. RSLV treatment induced production of chaperon proteins, and the RSLV-treated Arabidopsis thus demonstrated enhanced abiotic stress tolerance. Because oxidative stress treatment enhanced RSLV production, we concluded that commonly found RSLVs produced by environmental stresses are powerful inducer of abiotic stress-related gene expression as oxidative stress signals.
    Scientific Reports 01/2015; 5:8030. DOI:10.1038/srep08030 · 5.58 Impact Factor
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    ABSTRACT: Photosystems of higher plants alleviate heat-induced damage in the presence of light under moderate stressed conditions; however, in the absence of light (i.e., in the dark), the same plants are damaged more easily. (Yamauchi and Kimura, 2011) We demonstrate that regulating photochemical energy transfer in heat-treated wheat at 40 °C with light contributed to heat tolerance of the photosystem. Chlorophyll fluorescence analysis using heat-stressed wheat seedlings in light showed increased non-photochemical quenching (NPQ) of chlorophyll fluorescence, which was due to thermal dissipation that was increased by state 1 to state 2 transition. Transmission electron microscopy revealed structural changes in thylakoid membranes, including unstacking of grana regions under heat stress in light. It was accompanied by the phosphorylation of thylakoid proteins such as D1 and D2 proteins and the light harvesting complex II proteins Lhcb1 and Lhcb2. These results suggest that heat stress at 40 °C in light induces state 1 to state 2 transition for the preferential excitation of photosystem I (PSI) by phosphorylating thylakoid proteins more strongly. Structural changes of thylakoid membrane also assist the remodeling of photosystems and regulation of energy distribution by transition toward state 2 probably contributes to plastoquione oxidation; thus, light-driven electrons flowing through PSI play a protective role against PSII damage under heat stress.
    International Journal of Molecular Sciences 12/2014; 15(12):23042-23058. DOI:10.3390/ijms151223042 · 2.86 Impact Factor
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    ABSTRACT: Root exudates of sunflower (Helianthus annuus L.) line 2607A induced germination of seeds of root parasitic weeds Striga hermonthica, Orobanche cumana, Orobanche minor, Orobanche crenata, and Phelipanche aegyptiaca. Bioassay-guided purification led to the isolation of a germination stimulant designated as heliolactone. FT-MS analysis indicated a molecular formula of C20H24O6. Detailed NMR spectroscopic studies established a methylfuranone group, a common structural component of strigolactones connected to a methyl ester of a C14 carboxylic acid via an enol ether bridge. The cyclohexenone ring is identical to that of 3-oxo-α-ionol and the other part of the molecule corresponds to an oxidized carlactone at C-19. It is a carlactone-type molecule and functions as a germination stimulant for seeds of root parasitic weeds. Heliolactone induced seed germination of the above mentioned root parasitic weeds, while dehydrocostus lactone and costunolide, sesquiterpene lactones isolated from sunflower root exudates, were effective only on O. cumana and O. minor. Heliolactone production in aquacultures increased when sunflower seedlings were grown hydroponically in tap water and decreased on supplementation of the culture with either phosphorus or nitrogen. Costunolide, on the other hand, was detected at a higher concentration in well-nourished medium as opposed to nutrient-deficient media, thus suggesting a contrasting contribution of heliolactone and the sesquiterpene lactone to the germination of O. cumana under different soil fertility levels.
    Phytochemistry 12/2014; 108. DOI:10.1016/j.phytochem.2014.09.018 · 2.55 Impact Factor
  • Kotomi Ueno · Yukihiro Sugimoto · Binne Zwanenburg
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    ABSTRACT: Alectrol was first isolated from root exudates of cowpea (Vigna unguiculata), a genuine host of a root parasitic weed Striga gesnerioides, as a germination stimulant for seeds of the parasite. The proposed structure, an isomer of strigol, was disproven by chemical synthesis. Recently, another structure, namely orobanchyl acetate, was proposed. Surprisingly, however, the synthetic compound having this proposed structure for alectrol was not active in inducing germination of S. gesnerioides seeds although it was active toward seeds of other root parasitic weeds such as S. hermonthica and Orobanche minor. Detailed studies on 1H NMR, mass and CD spectra of naturally occurring alectrol, re-isolated from cowpea root exudates, revealed that the genuine structure of the germination stimulant is not orobanchyl acetate but its stereoisomer ent-2′-epi-orobanchyl acetate. Accordingly, the structure of natural orobanchol was revised to ent-2′-epi-orobanchol 12 years after a tentative structure of orobanchol was proposed. Strict stereochemical requirements of strigolactones for germination induction of S. gesnerioides seeds, authentic samples of synthetic strigolactones and advanced analytical instruments made the structural assignment possible, thus ending a 20 years controversy concerning the true structure of alectrol.
    Phytochemistry Reviews 09/2014; 14(5). DOI:10.1007/s11101-014-9380-2 · 2.41 Impact Factor
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    ABSTRACT: The gas exchange of the upper fully expanded leaf of the root parasite Striga hermonthica and of its host Sorghum bicolor was measured under wet and dry conditions to identify the mechanisms of the devastating effects of the parasite on its hosts under drought. The short-term water stress severely reduced photosynthetic rate in infected sorghum, but less in S. hermonthica. Soil water stress did not affect leaf respiration rate in either S. hermonthica or infected sorghum. This suggests that under dry conditions both infected sorghum and S. hermonthica decreased autotrophic carbon gain. The transpiration rate of S. hermonthica, a major driving force for assimilate uptake from the host, was higher and less affected by water stress than that of infected sorghum. Stomatal density on the abaxial surfaces of the leaves was higher in S. hermonthica than in sorghum. Both S. hermonthica infection and water stress decreased stomatal conductance of the sorghum leaves. S. hermonthica, irrespective of soil water status, had greater stomatal aperture on the adaxial and abaxial surfaces of its leaves than infected sorghum. These results indicate that the higher transpiration rate of S. hermonthica even under water stress, achieved through higher stomatal density on the abaxial surfaces of the leaves and greater stomatal aperture on both surfaces of the leaves, may induce the maintenance of water and solutes transfer from the host to the parasite leading to severe damage to the host under drought.
    Biologia Plantarum 12/2013; 57(4). DOI:10.1007/s10535-013-0348-7 · 1.85 Impact Factor
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    ABSTRACT: Strigolactones, important rhizosphere signalling molecules and a class of phytohormones that control shoot architecture, are apocarotenoids of plant origin. They have a structural core consisting of a tricyclic lactone connected to a butyrolactone group via an enol ether bridge. Deuterium-labelled 5-deoxystrigol stereoisomers were administered to aquacultures of a high sorgomol-producing sorghum cultivar, Sorghum bicolor (L.) Moench, and conversion of these substrates to sorgomol stereoisomers was investigated. Liquid chromatography-mass spectrometry analyses established that 5-deoxystrigol (5-DS) and ent-2'-epi-5-deoxystrigol were absorbed by sorghum roots, converted to sorgomol and ent-2'-epi-sorgomol, respectively, and exuded out of the roots. The conversion was inhibited by uniconazole-P, implying the involvement of cytochrome P450 in the hydroxylation. These results provide experimental evidence for the postulated biogenetic scheme for formation of strigolactones, in which hydroxylation at C-9 of 5-DS can generate sorgomol.
    Phytochemistry 04/2013; 93. DOI:10.1016/j.phytochem.2013.02.017 · 2.55 Impact Factor
  • Masashi Tanaka · Yukihiro Sugimoto · Masaki Kuse · Hirosato Takikawa
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    ABSTRACT: A straightforward synthesis of 7-oxo-5-deoxystrigol, a 7-oxygenated strigolactone analog, was achieved by starting from 2,2-dimethylcyclohexane-1,3-dione.
    Bioscience Biotechnology and Biochemistry 04/2013; 77(4). DOI:10.1271/bbb.130020 · 1.06 Impact Factor
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    ABSTRACT: Key message: Structure-activity relationship studies of strigolactones and Striga gesnerioides seed germination revealed strict structural requirements for germination induction and a new function of the plant hormones as germination inhibitors. Stereoisomers of the naturally occurring strigolactones, strigol, sorgolactone, orobanchol, sorgomol and 5-deoxystrigol, 36 in total, were prepared and screened for the ability to induce and/or inhibit the germination of Striga hermonthica and Striga gesnerioides seeds collected from mature plants that parasitized on sorghum and cowpea, respectively. All of the compounds induced S. hermonthica seed germination, albeit displayed differential activities. On the other hand, only a limited number of the compounds induced significant germination in S. gesnerioides, thus indicating strict structural requirements. Strigolactones inducing high germination in S. gesnerioides induced low germination in S. hermonthica. Strigolactones with the same configuration at C3a, C8b and C2' as that in 5-deoxystrigol (9a) induced high germination of S. hermonthica seeds, but most of them inhibited the germination of S. gesnerioides. The differential response of S. gesnerioides to strigolactones may play an important role in the survival of the species. However, the compounds could be used as means of control if mixed cropping of cowpea and sorghum is adopted.
    Plant Cell Reports 04/2013; 32(6). DOI:10.1007/s00299-013-1429-y · 3.07 Impact Factor
  • Kotomi Ueno · Hirosato Takikawa · Yukihiro Sugimoto
    01/2013; 51(1):36-42. DOI:10.1271/kagakutoseibutsu.51.36
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    ABSTRACT: Under a moderately heat-stressed condition, the photosystems of higher plants are damaged in the dark more easily than they are in the presence of light. To obtain a better understanding of this heat-derived damage mechanism that occurs in the dark, we focused on the involvement of the light-independent electron flow that occurs at 40 °C during the damage. In various plant species, the maximal photochemical quantum yield of photosystem (PS) II (Fv/Fm) decreased as a result of heat treatment in the dark. In the case of wheat, the most sensitive plant species tested, both Fv/Fm and oxygen evolution rapidly decreased by heat treatment at 40 °C for 30 min in the dark. In the damage, specific degradation of D1 protein was involved, as shown by immunochemical analysis of major proteins in the photosystem. Because light canceled the damage to PSII, the light-driven electron flow may play a protective role against PSII damage without light. Light-independent incorporation of reducing power from stroma was enhanced at 40 °C but not below 35 °C. Arabidopsis mutants that have a deficit of enzymes which mediate the incorporation of stromal reducing power into thylakoid membranes were tolerant against heat treatment at 40 °C in the dark, suggesting that the reduction of the plastoquinone pool may be involved in the damage. In conclusion, the enhanced introduction of reducing power from stroma into thylakoid membranes that occurs around 40 °C causes over-reduction of plastoquinone, resulting in the damage to D1 protein under heat stress without linear electron flow.
    Planta 04/2012; 236(2):753-61. DOI:10.1007/s00425-012-1647-5 · 3.26 Impact Factor
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    Yasuo Yamauchi · Ayaka Hasegawa · Masaharu Mizutani · Yukihiro Sugimoto
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    ABSTRACT: Lipid peroxide-derived reactive carbonyls (RCs) can cause serious damage to plant functions. A chloroplastic NADPH-dependent alkenal/one oxidoreductase (AOR) detoxifies RCs, but its physiological significance remains unknown. In this study, we investigated the biological impacts of AOR using an AOR-knock out Arabidopsis line (aor). Methyl viologen treatment, mainly to enhance photosystem (PS) I-originated reactive oxygen species (ROS) production, caused more severe damage to aor than wild type (Col-0). In contrast, the high light treatment used to enhance PSII-originated ROS production resulted in no difference in PSII damage between Col-0 and aor. In conclusion, AOR can contribute to detoxify stromal RCs produced under oxidative stress.
    FEBS letters 04/2012; 586(8):1208-13. DOI:10.1016/j.febslet.2012.03.013 · 3.17 Impact Factor
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    ABSTRACT: Coumarins are important compounds that contribute to the adaptation of plants to biotic or abiotic stresses. Among coumarins, umbelliferone occupies a pivotal position in the plant phenylpropanoid network. Previous studies indicated that umbelliferone is derived from the ortho-hydroxylation of p-coumaric acid by an unknown biochemical step to yield 2,4-dihydroxycinnamic acid, which then undergoes spontaneous lactonization. Based on a recent report of a gene encoding a 2-oxoglutarate-dependent dioxygenase from Arabidopsis thaliana that exhibited feruloyl CoA 6'-hydroxylase activity (Bourgaud et al., 2006), we combined a bioinformatic approach and a cDNA library screen to identify an orthologous ORF (Genbank accession number JF799117) from Ruta graveolens L. This ORF shares 59% amino acid identity with feruloyl CoA 6'-hydroxylase, was functionally expressed in Escherichia coli, and converted feruloyl CoA into scopoletin and p-coumaroyl CoA into umbelliferone with equal activity. Its bi-functionality was further confirmed in planta: transient expression of JF799117 in Nicotiana benthamiana yielded plants with leaves containing high levels of umbelliferone and scopoletin when compared to control plants, which contained barely detectable traces of these compounds. The expression of JF799117 was also tightly correlated to the amount of umbelliferone that was found in UV-elicited R. graveolens leaves. Therefore, JF799117 encodes a p-coumaroyl CoA 2'-hydroxylase in R. graveolens, which represents a previously uncharacterized step in the synthesis of umbelliferone in plants. Psoralen, which is an important furanocoumarin in R. graveolens, was found to be a competitive inhibitor of the enzyme, and it may exert this effect through negative feedback on the enzyme at an upstream position in the pathway.
    The Plant Journal 12/2011; 70(3):460-70. DOI:10.1111/j.1365-313X.2011.04879.x · 5.97 Impact Factor
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    ABSTRACT: Striga gesnerioides is a root parasitic weed of economic significance to cowpea (Vigna unguiculata) crops in Western Africa. Seeds of the parasite germinate in response to cowpea root exudates. Germination stimulants for the seeds were isolated from the hydroponic culture filtrate of cowpea, and their structures were unambiguously determined as (-)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchol and (+)-(3aR,4R,8bR,2'R)-ent-2'-epi-orobanchyl acetate, on the basis of mass, CD, and (1)H NMR spectra; optical rotatory power; and chromatographic behavior on HPLC. The alcohol was first isolated and identified from the cowpea root exudates, and the acetate may be the same compound that had been previously isolated from the exudates and designated as alectrol. Identity of the stimulants produced by cowpea to those produced by red clover (Trifolium pratense) was confirmed.
    Journal of Agricultural and Food Chemistry 09/2011; 59(19):10485-90. DOI:10.1021/jf2024193 · 2.91 Impact Factor
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    ABSTRACT: Strigolactones are highly potent germination stimulants for seeds of the parasitic weeds Striga and Orobanche spp. 4-Hydroxy-GR24 and 4-acetoxy-GR24 were prepared and their abilities to induce seed germination of Striga gesnerioides evaluated. Optically active (8bR,2'R)-isomers induced germination, although the racemic diastereomers were inactive. In contrast, the stereoisomer of GR24 with the same configuration induced negligible germination. Some stereoisomers of GR24 and its analogues acted as effective antagonists for induction of seed germination by cowpea root exudates. These results suggest that both an oxygenated substituent at C-4 and the configuration of the tricyclic lactone and the D-ring are essential structural requirements for induction of germination in S. gesnerioides seeds.
    Journal of Agricultural and Food Chemistry 08/2011; 59(17):9226-31. DOI:10.1021/jf202418a · 2.91 Impact Factor
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    ABSTRACT: Sorgomol, isolated from Sorghum bicolor, is the germination stimulant for seeds of root parasitic weeds. The first synthesis of (±)-sorgomol has been achieved by starting from ethyl 2-oxocyclohexanecarboxylate.
    Tetrahedron Letters 02/2011; 52(6):724-726. DOI:10.1016/j.tetlet.2010.12.010 · 2.38 Impact Factor
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    ABSTRACT: Reactive carbonyls, especially α,β-unsaturated carbonyls produced through lipid peroxidation, damage biomolecules such as proteins and nucleotides; elimination of these carbonyls is therefore essential for maintaining cellular homeostasis. In this study, we focused on an NADPH-dependent detoxification of reactive carbonyls in plants and explored the enzyme system involved in this detoxification process. Using acrolein (CH(2) = CHCHO) as a model α,β-unsaturated carbonyl, we purified a predominant NADPH-dependent acrolein-reducing enzyme from cucumber leaves, and we identified the enzyme as an alkenal/one oxidoreductase (AOR) catalyzing reduction of an α,β-unsaturated bond. Cloning of cDNA encoding AORs revealed that cucumber contains two distinct AORs, chloroplastic AOR and cytosolic AOR. Homologs of cucumber AORs were found among various plant species, including Arabidopsis, and we confirmed that a homolog of Arabidopsis (At1g23740) also had AOR activity. Phylogenetic analysis showed that these AORs belong to a novel class of AORs. They preferentially reduced α,β-unsaturated ketones rather than α,β-unsaturated aldehydes. Furthermore, we selected candidates of other classes of enzymes involved in NADPH-dependent reduction of carbonyls based on the bioinformatic information, and we found that an aldo-keto reductase (At2g37770) and aldehyde reductases (At1g54870 and At3g04000) were implicated in the reduction of an aldehyde group of saturated aldehydes and methylglyoxal as well as α,β-unsaturated aldehydes in chloroplasts. These results suggest that different classes of NADPH-dependent reductases cooperatively contribute to the detoxification of reactive carbonyls.
    Journal of Biological Chemistry 12/2010; 286(9):6999-7009. DOI:10.1074/jbc.M110.202226 · 4.57 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 09/2010; 32(37). DOI:10.1002/chin.200137207

Publication Stats

1k Citations
209.12 Total Impact Points


  • 2004–2015
    • Kobe University
      • • Graduate School of Agricultural Science
      • • Department of Agrobioscience
      • • Department of Biofunctional Chemistry
      Kōbe, Hyōgo, Japan
  • 1993–2010
    • Tottori University
      • Arid Land Research Center
      TTJ, Tottori, Japan
    • Hitachi, Ltd.
      Edo, Tōkyō, Japan
  • 2008
    • Utsunomiya University
      • Weed Science Center
      Totigi, Tochigi, Japan
  • 1988–2004
    • Kyoto University
      Kioto, Kyōto, Japan
  • 2002
    • Chinese Academy of Sciences
      Peping, Beijing, China
  • 2001
    • Nara Women's University
      • Graduate School of Human Culture
      Nara, Nara, Japan