記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) are apocarotenoid plant hormones that regulate shoot branching. The natural SLs can be divided into two groups, canonical and non-canonical SLs according to those chemical structures. In a model plant, Arabidopsis thaliana, it has been thought to produce only non-canonical SLs. Moreover, in rice, it was suggested that canonical-SL such as 4-deoxyorobanchol (4DO) does not have a critical role in shoot branching inhibition. In this report, to understand the potential of canonical-SL in shoot branching inhibition pathway in Arabidopsis, SL biosynthetic genes involved in canonical-SL production in other plant species were individually expressed in Arabidopsis. Our data clearly demonstrate that 5-deoxystrigol, but not 4DO, can inhibit shoot branching in Arabidopsis. Moreover, the results confirmed the important role of CLA methyltransferase (CLAMT) in shoot branching inhibition pathway in Arabidopsis.

DOI： 10.1093/bbb/zbae202

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Phtheirospermum japonicum, a member of the Orobanchaceae family, is a facultative root parasitic plant that can survive without parasitizing the host. In contrast, obligate root parasitic plants such as Striga and Orobanche, which are also members of the Orobanchaceae family, cannot survive in the absence of the host. The germination of obligate root parasitic plants is typically induced by host root-derived strigolactones (SLs) at very low concentrations. The KAI2/HTL family proteins have been found to be involved in the perception of karrikin (KAR), a smoke-derived germination inducer and unidentified endogenous ligand, in non-parasitic plants. Obligate root parasitic plants possess uniquely diverged KAI2 clade genes, which are collectively referred to as KAI2d. Many of those have been shown to function as SL receptors. Intriguingly, the KAI2d clade genes are also conserved in P. japonicum, even though this plant does not require SLs for germination. The biochemical and physiological functions of the KAI2d proteins in P. japonicum remain unclear. Here, we report that some of these proteins can function as SL receptors in P. japonicum. Moreover, we found that one of them, PjKAI2d4, is highly sensitive to SLs when expressed in Arabidopsis, and it is similar to the sensitive SL receptors found in Striga and Orobanche. These results suggest that the KAI2d clade SL receptors play a crucial role not only in obligate parasites but also in facultative parasitic plants.

DOI： 10.1093/pcp/pcae105

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記述言語：英語  

DOI： 10.1021/acs.jafc.4c05797

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Root parasitic plants in the Orobancheceae, such as Striga and Orobanche, cause significant damage to crop production. The germination step of these root parasitic plants is induced by host-root-derived strigolactones (SLs). After germination, the radicles elongate toward the host and invade the host root. We have previously discovered that a simple amino acid, tryptophan (Trp), as well as its metabolite, the plant hormone indole-3-acetic acid (IAA), can inhibit radicle elongation of Orobanche minor. These results suggest that auxin plays a crucial role in the radicle elongation step in root parasitic plants. In this report, we used various auxin chemical probes to dissect the auxin function in the radicle growth of O. minor and Striga hermonthica. We found that synthetic auxins inhibited radicle elongation. In addition, auxin receptor antagonist, auxinole, rescued the inhibition of radicle growth by exogenous IAA. Moreover, a polar transport inhibitor of auxin, N-1-naphthylphthalamic acid (NPA), affected radicle bending. We also proved that exogenously applied Trp is converted into IAA in O. minor seeds, and auxinole partly rescued this radicle elongation. Our data demonstrate a pivotal role of auxin in radicle growth. Thus, manipulation of auxin function in root parasitic plants should offer a useful approach to combat these parasites.

DOI： 10.1093/pcp/pcae071

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactone is the collective name for compounds containing a butenolide as a part of their structure, first discovered as compounds that induce seed germination of root parasitic plants. They were later found to be rhizosphere signaling molecules that induce hyphal branching of arbuscular mycorrhizal fungi, and, finally, they emerged as a class of plant hormones. Strigolactones are found in root exudates, where they display a great variability in their chemical structure. Their structure varies among plant species, and multiple strigolactones can exist in one species. Over 30 strigolactones have been identified, yet the chemical structure of the strigolactone that functions as an endogenous hormone and is found in the above-ground parts of plants remains unknown. We discuss our current knowledge of the synthetic pathways of diverse strigolactones and their regulation, as well as recent progress in identifying strigolactones as plant hormones. Strigolactone is perceived by the DWARF14 (D14), receptor, an α/β hydrolase which originated by gene duplication of KARRIKIN INSENSITIVE 2 (KAI2). D14 and KAI2 signaling pathways are partially overlapping paralogous pathways. Progress in understanding the signaling mechanisms mediated by two α/β hydrolase receptors as well as remaining challenges in the field of strigolactone research are reviewed.

DOI： 10.1093/jxb/erad412

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) are a class of terpenoid lactones initially identified as seed germination stimulants for root parasitic plants more than 50 years ago. Long after this initial discovery, SLs were re-characterized as the symbiotic signals for arbuscular mycorrhizal fungi that supply inorganic nutrients, such as phosphate, to their host plants. In 2008, SLs were found to be endogenous plant hormones that regulate shoot branching in plants. The discovery of SLs as a new class of plant hormones has significantly advanced research in this field. Studies over the past 15 years have elucidated almost the entire pathway of SL biosynthesis and the overall mechanism of its signaling. This review summarizes research on the SL biosynthetic pathway, and the current state of knowledge of the SL perception mechanism.

DOI： 10.1093/bbb/zbad150

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) are a class of plant hormones that regulate many aspects of plant growth and development. SLs also improve symbiosis with arbuscular mycorrhizal fungi (AMF) in the rhizosphere. Recent studies have shown that the DWARF14-LIKE (D14L)/KARRIKIN-INSENSITIVE2 (KAI2) family, paralogs of the SL receptor D14, are required for AMF colonization in several flowering plants, including rice. In this study, we found that (-)-GR5, a 2'S-configured enantiomer of a synthetic SL analog (+)-GR5, significantly activated SL biosynthesis in rice roots via D14L. This result is consistent with a recent report, showing that the D14L pathway positively regulates SL biosynthesis in rice. In fact, the SL levels tended to be lower in the roots of the d14l mutant under both inorganic nutrient-deficient and -sufficient conditions. We also show that the increase in SL levels by (-)-GR5 was observed in other mycorrhizal plant species. In contrast, the KAI2 pathway did not upregulate the SL level and the expression of SL biosynthetic genes in Arabidopsis, a non-mycorrhizal plant. We also examined whether the KAI2 pathway enhances SL biosynthesis in the liverwort Marchantia paleacea, where SL functions as a rhizosphere signaling molecule for AMF. However, the SL level and SL biosynthetic genes were not positively regulated by the KAI2 pathway. These results imply that the activation of SL biosynthesis by the D14L/KAI2 pathway has been evolutionarily acquired after the divergence of bryophytes to efficiently promote symbiosis with AMF, although we cannot exclude the possibility that liverworts have specifically lost this regulatory system.

DOI： 10.1093/pcp/pcad079

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/pcp/pcad095

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs), phytohormones that inhibit shoot branching in plants, promote the germination of root-parasitic plants, such as Striga spp. and Orobanche spp., which drastically reduces the crop yield. Therefore, reducing SL production via chemical treatment may increase the crop yield. To design specific inhibitors, it is valid to utilize the substrate structure of the target proteins as lead compounds. In this study, we focused on Os900, a rice enzyme that oxidizes the SL precursor carlactone (CL) to 4-deoxyorobanchol (4DO), and synthesized 10 CL derivatives. The effects of the synthesized CL derivatives on SL biosynthesis were evaluated by the Os900 enzyme assay in vitro and by measuring 4DO levels in rice root exudates. We identified some CL derivatives that inhibited SL biosynthesis in vitro and in vivo.

DOI： 10.1021/acsomega.3c00098

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) were initially discovered as germination inducers for root parasitic plants. In 2015, three groups independently reported the characterization of the SL receptor in the root parasitic plant Striga hermonthica, which causes significant damage to crop production, particularly in sub-Saharan Africa. The characterized receptors belong to HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE2 (HTL/KAI2), which is a member of the α/β-hydrolase protein superfamily. In non-parasitic plants, HTL/KAI2 perceives the smoke-derived germination inducer karrikin and a yet-unidentified endogenous ligand. However, root parasitic plants evolved a specific clade of HTL/KAI2 that has diverged from the KAI2 clade of non-parasitic plants. The S. hermonthica SL receptors are included in this specific clade, which is called KAI2 divergent (KAI2d). Orobanche minor is an obligate root holoparasitic plant that grows completely dependent on the host for water and nutrients because of a lack of photosynthetic ability. Previous phylogenetic analysis of KAI2 proteins in O. minor has demonstrated the presence of at least five KAI2d clade genes. Here, we report that KAI2d3 and KAI2d4 in O. minor have the ability to act as the SL receptors. They directly interact with SLs in vitro, and when expressed in Arabidopsis, they rescue thermo-inhibited germination in response to the synthetic SL analog GR24. In particular, KAI2d3 showed high sensitivity to GR24 when expressed in Arabidopsis, suggesting that this receptor enables highly sensitive SL recognition in O. minor. Furthermore, we provide evidence that these KAI2d receptors are involved in the perception of sesquiterpene lactones, non-strigolactone-type germination inducers.

DOI： 10.1093/pcp/pcad026

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.bbrc.2023.01.086

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

SignificanceStrigolactones (SLs) are a group of apocarotenoid hormones, which regulates shoot branching and other diverse developmental processes in plants. The major bioactive form(s) of SLs as endogenous hormones has not yet been clarified. Here, we identify an Arabidopsis methyltransferase, CLAMT, responsible for the conversion of an inactive precursor to a biologically active SL that can interact with the SL receptor in vitro. Reverse genetic analysis showed that this enzyme plays an essential role in inhibiting shoot branching. This mutant also contributed to specifying the SL-related metabolites that could move from root to shoot in grafting experiments. Our work has identified a key enzyme necessary for the production of the bioactive form(s) of SLs.

DOI： 10.1073/pnas.2111565119

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Root parasitic plants such as Striga and Orobanche cause significant damage on crop production, particularly in sub-Saharan Africa. Their seeds germinate by sensing host root-derived signaling molecules called strigolactones (SLs). SL mimics can be used as suicidal germination inducers for root parasitic plants. Previous attempts to develop such chemicals have revealed that the methylbutenolide ring (D-ring), a common substructure in all the naturally occurring SLs, is critical for SL agonistic activity, suggesting that it should be possible to generate new SL mimics simply by coupling a D-ring with another molecule. Because structural information regarding SLs and their receptor interaction is still limited, such an approach might be an effective strategy to develop new potent SL agonists. Here, we report development of a series of new SL analogs derived from cinnamic acid (CA), the basis of a class of phenylpropanoid natural products that occur widely in plants. CA has an aromatic ring and a double-bond side-chain structure, which are advantageous for preparing structurally diverse derivatives. We prepared SL analogs from cis and trans configuration CA, and found that all the cis-CA-derived SL analogs had stronger activities as seed germination inducers for the root parasitic plants, Orobanche minor and Striga hermonthica, compared with the corresponding trans-CA-derived analogs. Moreover, introduction of a substitution at the C-4 position increased the germination-stimulating activity. We also found that the SL analogs derived from cis-CA were able to interact directly with SL receptor proteins more effectively than the analogs derived from trans-CA. The cis isomer of CA was previously reported to have a growth promoting effect on non-parasitic plants such as Arabidopsis. We found that SL analogs derived from cis-CA also showed growth promoting activity toward Arabidopsis, suggesting that these new SL agonists might be useful not only as suicidal germination inducers for root parasitic weeds, but also as plant growth promoters for the host plants.

DOI： 10.3389/fpls.2022.843362

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Root parasitic plant germination is induced by the host-derived chemical, strigolactone (SL). We found that a major microbial culture broth component, tryptone, inhibits the SL-inducible germination of a root parasitic plant, Orobanche minor. l-tryptophan (l-Trp) was isolated as the active compound from tryptone. We further found that l-Trp related compounds (1b-11), such as a major plant hormone auxin (8, indole-3-acetic acid; IAA), also inhibit the germination and post-radicle growth of O. minor. We designed a hybrid chemical (13), in which IAA is attached to a part of SL, and found that this synthetic analog induced the germination of O. minor, and also inhibited post-radicle growth. Moreover, contrary to our expectations, we found that N-acetyl Trp (9) showed germination stimulating activity, and introduction of a substitution at C-5 position increased its activity (12a-12f). Our data, in particular, the discovery of a structurally hybrid compound that has two activities that induce spontaneous germination and inhibit subsequent radical growth, would provide new types of germination regulators for root parasitic plants.

DOI： 10.1016/j.bmcl.2021.128085

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Small-molecule plant hormones principally control plant growth, development, differentiation, and environmental responses. Nine types of plant hormones are ubiquitous in angiosperms, and the molecular mechanisms of their hormone actions have been elucidated during the last two decades by genomic decoding of model plants with genetic mutants. In particular, the discovery of hormone receptors has greatly contributed to the understanding of signal transduction systems. The three-dimensional structure of the ligand-receptor complex has been determined for eight of the nine hormones by X-ray crystal structure analysis, and ligand perception mechanisms have been revealed at the atomic level. Collective research has revealed the molecular function of plant hormones that act as either molecular glue or an allosteric regulator for activation of receptors. In this review, we present an overview of the respective hormone signal transduction and describe the structural bases of ligand-receptor interactions.

DOI： 10.1111/tpj.15115

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) are plant hormones that regulate diverse developmental processes and environmental responses. They are also known to be root-derived chemical signals that regulate symbiotic and parasitic interactions with arbuscular mycorrhizal fungi and root parasitic plants, respectively. Since the discovery of the hormonal function of SLs in 2008, there has been much progress in the SL research field. In particular, a number of breakthroughs have been achieved in our understanding of SL biosynthesis, transport and perception. The discovery of the hormonal function of SL was quite valuable not only as the identification of a new class of plant hormones, but also as the discovery of the long-sought-after SL biosynthetic and response mutants. These mutants in several plant species provided us the genetic resources to address fundamental questions regarding SL biosynthesis and perception. Such mutants were further characterized later, and biochemical analyses of these genetically identified factors have uncovered the outline of SL biosynthesis and perception so far. Moreover, new genes involved in SL transport have been discovered through reverse genetic analyses. In this review, we summarize recent advances in SL research with a focus on biosynthesis, transport and perception.

DOI： 10.1111/tpj.15059

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記述言語：日本語  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Strigolactones (SLs) are a group of plant apocarotenoids that act as rhizosphere signaling molecules for both arbuscular mycorrhizal fungi and root parasitic plants. They also regulate plant architecture as phytohormones. The model legume Lotus japonicus (synonym of Lotus corniculatus) produces canonical 5-deoxystrigol (5DS) and non-canonical lotuslactone (LL). The biosynthesis pathways of the two SLs remain elusive. In this study, we characterized the L. japonicus MAX1 homolog, LjMAX1, found in the Lotus japonicus genome assembly build 2.5. The L. japonicus max1 LORE1 insertion mutant was deficient in 5DS and LL production. A recombinant LjMAX1 protein expressed in yeast microsomes converted carlactone (CL) to 18-hydroxycarlactonoic acid (18-OH-CLA) via carlactonoic acid (CLA). Identity of 18-OH-CLA was confirmed by comparison of the methyl ester derivative of the MAX1 product with chemically synthesized methyl 18-hydroycarlactonoate (18-OH-MeCLA) using LC-MS/MS. (11R)-CL was detected as an endogenous compound in the root of L. japonicus.13C-labeled CL, CLA, and 18-OH-MeCLA were converted to [13C]-5DS and LL in plant feeding experiments using L. japonicus WT. These results showed that LjMAX1 is the crucial enzyme in the biosynthesis of Lotus SLs and that 18-hydroxylated carlactonoates are possible precursors for SL biosynthesis in L. japonicus.

DOI： 10.1016/j.phytochem.2020.112349

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41467-018-08124-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Parasitic plants in the genus Striga, commonly known as witchweeds, cause major crop losses in sub-Saharan Africa and pose a threat to agriculture worldwide. An understanding of Striga parasite biology, which could lead to agricultural solutions, has been hampered by the lack of genome information. Here, we report the draft genome sequence of Striga asiatica with 34,577 predicted protein-coding genes, which reflects gene family contractions and expansions that are consistent with a three-phase model of parasitic plant genome evolution. Striga seeds germinate in response to host-derived strigolactones (SLs) and then develop a specialized penetration structure, the haustorium, to invade the host root. A family of SL receptors has undergone a striking expansion, suggesting a molecular basis for the evolution of broad host range among Striga spp. We found that genes involved in lateral root development in non-parasitic model species are coordinately induced during haustorium development in Striga, suggesting a pathway that was partly co-opted during the evolution of the haustorium. In addition, we found evidence for horizontal transfer of host genes as well as retrotransposons, indicating gene flow to S. asiatica from hosts. Our results provide valuable insights into the evolution of parasitism and a key resource for the future development of Striga control strategies.

DOI： 10.1016/j.cub.2019.07.086

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.bmcl.2019.01.010

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DOI： 10.1016/j.celrep.2019.01.003

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DOI： 10.1111/tpj.14017

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掲載種別：研究論文（学術雑誌）   出版者・発行元：American Association for the Advancement of Science (AAAS)  

DOI： 10.1126/science.aat1577

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記述言語：日本語   出版者・発行元：一般社団法人 植物化学調節学会  

<p>Strigolactones （SLs）are plant hormones that regulate shoot branching as well as being known as rhizosphere signals for parasitic and symbiotic interactions. In 2012, an SL-like molecule called carlactone （CL） was identified through the biochemical functional analysis of three enzymes, CAROTENOID CLEAVAGE DIOXYGENASE7 （CCD7）, CCD8, and DWARF27 （D27）, yet its natural occurrence in plant tissue was not proved. Using a chemically synthesized stable isotope labeled CL as an internal standard we successfully identified CL as an endogenous metabolite both in rice and Arabidopsis by LC-MS/MS analysis. Moreover, we proved bioconversion of CL into some SL molecules in rice, conclusively demonstrating that CL is an endogenous biosynthetic precursor for SLs. In addition, we found that CL is converted into its carboxylated analog, carlactonic acid （CLA）, in a manner dependent on a cytochrome P450, <i>MAX1</i>. We also identified a methyl esterified derivative of CLA, methyl carlactonoate （MeCLA）, as an endogenous SL-like molecule in Arabidopsis. Intriguingly, among three CL-related molecules （CL, CLA, MeCLA）, only MeCLA could physically interact with the SL receptor protein, AtD14, suggesting that the methyl esterification step of CLA has a critical role to produce bioactive hormone compounds in the shoot branching inhibition pathway.</p>

DOI： 10.18978/jscrp.53.1_27

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記述言語：日本語   出版者・発行元：一般社団法人植物化学調節学会  

<p>Strigolactones （SLs）, which were initially characterized as seed germination stimulants for root parasitic plants about 50 years ago, are now known as symbiotic signals for arbuscular mycorrhizal fungi as well as plant hormones that regulate shoot branching and so on. The discovery of SLs as a new class of plant hormones in 2008 was also significant as an initial characterization of SL biosynthetic mutants, which greatly facilitated its biosynthetic studies. In 2012, an SL-like compound called carlactone （CL） was identified from <i>in vitro</i> biochemical studies using three recombinant proteins of biosynthetic enzymes. The discovery of CL further moved ahead with this research field, and so far the nearly entire picture of the SL biosynthetic pathway has been unveiled. In this review, we will introduce the latest knowledge on the SL biosynthetic pathway as well as current efforts toward the characterization of the bioactive forms of SLs as plant hormones.</p>

DOI： 10.18978/jscrp.51.2_97

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.sbi.2016.08.005

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記述言語：英語  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1601729113

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記述言語：英語  

DOI： 10.3389/fpls.2015.00617

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/pcp/pcv028

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記述言語：日本語   出版者・発行元：一般社団法人植物化学調節学会  

<p>The apoplast is the space outside the plasma membrane, consisting of the cell wall and its outer space. The apoplastic solution contains a wide variety of small molecules, some of which are taken up from soil with water. In addition, some chemicals biosynthesized in the cell are secreted into the apoplastic region through the plasma membrane. Xylem sap contains many of these small chemicals including signaling molecules, thus the apoplastic region has an important role in the translocation of these small signaling molecules. In this review, we describe recent topics on the movement and functions of selected hormonal molecules that are transported over a long distance through the xylem. In a broad sense, the long distance translocation of signaling molecules through the apoplast can be considered as a part of "the information processing system of the plant cell wall".</p>

DOI： 10.18978/jscrp.50.1_70

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/tpj.12731

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記述言語：日本語   出版者・発行元：天然有機化合物討論会実行委員会  

<p>【目 的】</p><p> 植物は大地に根を張り移動が困難である事から、自己の被る様々な環境要因，ストレスに適応して生活環を終結させなくてはならない。よって、植物は独自の環境応答機構を有している。この応答機構を司る生理活性物質として植物ホルモンと呼称される一群の化合物が知られ、多くの研究がなされてきた。我々の研究室では長年、植物ホルモンの一種であるジャスモン酸(JA)について、鋭意研究を行っている。JA類は植物の傷害応答シグナル物質として必須であり、他の興味ある生理活性としてバレイショ塊茎の誘導活性、植物の就眠運動における就眠誘導、花粉管伸長促進などが知られている。近年、JA類の生理活性の制御の観点から、配糖化、チトクロームP450による酸化などに注目した報告がある。</p><p> 我々はJA類の配糖体化に関して研究を進め、イネに含まれるOsSGTを12-hydroxyJA(12-OHJA)配糖化酵素として報告した[1]。OsSGT は糖供与体としてUDP-Glcを用いるが、12-OHJAよりサリチル酸(SA)に対してより高い糖転位活性を示した。しかしながら、本酵素の探索過程において、SAに対してほとんど配糖化活性を示さず、12-OHJAに特異性の高いUDP-Glc非依存性の配糖化酵素の存在も明らかとした。現在のところ、UDP-Glc非依存性の植物2次代謝産物を標的とした配糖化酵素に関しては松葉らの報告[2]があるのみであり、植物ホルモンの配糖体化に関してUDP-Glc非依存性の糖転位酵素が関与しているとの報告は一切無い。</p><p> 上記の興味ある発見の詳細を明らかとすべく我々は、1）イネカルスに含まれるUDP-Glc非依存性の配糖化酵素の精製、2）イネカルスに含まれる本配糖化酵素の糖供与体の単離精製、構造決定,3）本配糖化酵素の諸性質の究明を進めたところ、本配糖化酵素はb−glucosydase, OsBGlu1 （accession number: AK100165）であると突き止め、イネにおいてサリチル酸グルコシド(SAG)が糖供与体として働くことを明らかとした(図1)。本酵素の生理学的意義は水酸化JA類を配糖化しJAの活性調節に寄与していると示唆できた事から、本成果について報告する。</p><p> </p><p>【研究方法および結果】</p><p>1. UDP-Glc非依存性配糖化酵素の発見</p><p> イネカルス粗酵素溶液にUDP-Glcを糖供与体としない12-OHJA 選択的な配糖化酵素が存在する事を、市販の糖供与体を用い、以下の実験より発見した。糖転位反応液としてイネカルスより抽出した粗酵素溶液、糖受容体としてJA水酸化体の一種である12-OHJA、糖供与体として市販のGlc 1-phosphate, TDP-Glc, octyl-Glc, UDP-Glcを用いて実験を行った。その結果、octyl-Glc はUDP-Glcよりも12-OHJAにより選択的に糖を供与し、SAはほとんど配糖化されなかった。</p><p>2. イネ由来のUDP-Glc非依存性配糖化酵素の同定</p><p> 12-OHJA選択的糖転位活性を指標に、イネカルス粗酵素溶液に含まれる糖転位酵素の同定を試みた。糖供与体としてoctyl-Glc、糖受容体として12-OHJAを用い、種々の精製操作の後、得られた精製タンパク質はペプチドマスフィンガープ</p><p>(View PDFfor the rest of the abstract.)</p>

DOI： 10.24496/tennenyuki.57.0_Oral14

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1410801111

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記述言語：英語  

DOI： 10.1016/j.pbi.2014.06.001

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記述言語：日本語  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1073/pnas.1314805111

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記述言語：日本語   出版者・発行元：一般社団法人 植物化学調節学会  

DOI： 10.18978/jscrpanb.49.Supplement_33

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記述言語：日本語   出版者・発行元：一般社団法人植物化学調節学会  

<p>Strigolactones (SLs) were initially characterized as root-derived signals for parasitic and symbiotic interactions with root parasitic plants and arbuscular mycorrhizal fungi. In 2008, SLs or the downstream metabolites were shown to act as endogenous phytohormones that regulate shoot branching. After the discovery, many researchers demonstrated that SLs play important biological roles in plant development. Moreover, biochemical functions of SL-biosynthetic enzymes have been uncovered. In this review, we summarize recent advances in SL researches regarding diverse biological roles and biosynthesis.</p>

DOI： 10.18978/jscrp.48.2_148

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/gtc.12025

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記述言語：英語  

DOI： 10.1093/pcp/pcs142

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1271/bbb.110454

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1271/bbb.90119

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.phytochem.2009.01.004

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1271/bbb.60700

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.phytochem.2005.08.020

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1271/bbb.69.1515

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/S0168-9452(03)00280-2

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：公益社団法人 日本生物工学会  

DOI： 10.34565/seibutsukogaku.100.2_85

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

DOI： 10.18978/jscrpanb.50.Supplement_57

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

Jasmonate is plant hormone that plays crucial roles in development and defense response. It has been shown that 7-iso-jasmonyl-L-isoleucine (JA-Ile) is the bioactive form involved in the jasmonate-mediated signaling pathway. The hormonal action of jasmonate in plants is controlled by the precise balance between its biosynthesis and catabolism. Recently, CYP94B3, JA-Ile 12-hydroxylase was considered one of important enzymes that played fine tuning system of active form. Here, we studied the metabolic pathway of JA-Ile started with 12-hydroxylation. Firstly, we synthesized 12-carboxy1JA-Ile and 12-O-D-β-glucopyranosy1JA-Ile, which were expected metabolites of 12-hydroxyJA-Ile. Secondly, the endogenous levels of the compounds in wounded leaves of wild type or cyp94b3 mutant were analyzed by UPLC-MS/MS. Both compounds accumulated and the amount of 12-O-D-β-glucopyranosy1JA-Ile in cyp94b3 mutant was lower than that in wild type. In other hands, the 12-carboxy1JA-Ile level was same in wildtype and cyp94b3 mutant. This result suggests 12-carboxy1JA-Ile is synthesized by enzyme different from CYP94B3. Finally, we investigated 12-hydroxyJA-Ile glucosyltransferase. The enzyme which converted 12-hydroxyJA to 12-O-D-P-glucopyranosy1JA also had activity when 12-hydroxyJA-Ile was used as substrate. Currently, we survey the biological activity of 12-carboxy1JA-Ile and 12-O-D-13-glucopyranosy1JA-Ile.

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記述言語：日本語  

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記述言語：日本語   出版者・発行元：植物化学調節学会  

Plant hormone, jasmonic acid (JA), has been recognized as a signal molecule involved in the wounding response. But two metabolites of JA, tuberonic acid (TA; 12-hydroxyjasmonic acid) and its β-glucoside (TAG) have not been reported to show any clear physiological function on the wounding response. In order to establish functions of these compounds, we previously purified and characterized a glucosyltransferase in rice, that catalyzes the glucosylation from TA to TAG using UDPG as a glucose donor [1]. Moreover, we found out the existence of UDPG-independent one in the crude enzyme, that is more specific to TA than that one. In order to understand this glucosylation, we investigated a glucose donor except UDPG in this study. To test an activity of glucosyltranslation, we carried out TA glucosyltransferase assay using a crude enzyme in the rice cell culture. We used TA as a substrate and analyzed resulting TAG by UPLC-MS/MS. Using this assay system, an 80% ethanol extract derived from rice cell cultures (376.3 g) was purified by several series of column chromatography, and finally, compound 1 (1.5 mg) was obtained. The chemical structure of compound 1 is determined by NMR analysis that is to be 3-(4-hydroxyphenyl)prop-2-enyl β-D-glucopyranoside. This was synthesized from p-coumaric acid as starting compound, and the synthesized compound also transferred glucose to TA. Therefore, we concluded that compound 1 is a natural glucose donor in the rice cell culture.

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記述言語：日本語   出版者・発行元：植物化学調節学会  

Strigolactone (SL) was firstly identified as seed germination stimulants of parasitic plants such as Striga and Orobanche. Recently, SLs were identified as symbiotic signals of arbascular mycorhizal (AM) fungi that supply inorganic nutrients to the host plant. More recently SL or its metabolite has been identified as a novel plant hormone which inhibits shoot branching. Among tillering dwarf (d) mutants of rice, d10, d17, and d27 are biosynthetic mutants of SL. On the other hand d3 mutant is an F-box mutant, and this protein is thought to be involved in the signaling pathway of SL. Recently, we have discovered that d14 is an SL insensitive mutant and accumulates a higher amount of SL as does the d3 F-box mutant. The D14 gene encodes an α/β-fold-hydrolase family protein, and a soluble receptor of gibberellins, GID1, belongs to the same family. On the basis of these backgrounds, we can make two hypotheses for the biochemical function of D14 protein in the SL pathway; (1) D14 acts as a biosynthetic enzyme that converts SL to an active form of the hormone (2) D14 acts as a receptor of SL. To clarify the physiological role of D14 protein, we have been studying the biochemical function of D14 using recombinant D14 protein and synthetic radio-labeled SL.

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記述言語：日本語   出版者・発行元：植物化学調節学会  

Tuberonic acid (12-hydroxy epi-jasmonic acid, TA) and its glucoside (TAG) were isolated from potato leaflets (Solanum tuberosum L.) and shown to have tuber-inducing properties. These compounds are known to be biosynthesized by an octadecanoid pathway. The metabolism of jasmonic acid (JA) to TAG in plant leaflets and translocation of the resulting TAG to the distal parts was demonstrated. It is thought that TAG generated from JA transmits a wounded signal from damaged parts to undamaged parts by this mechanism. The metabolism of TA in higher plants was demonstrated using [12-^3H] TA, and TA ...

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記述言語：日本語   出版者・発行元：植物化学調節学会  

Plants respond to wounding and herbivore attack with a series of defense responses, which are put in motions locally and systemically. When the plants are suffered from wounding stress, a mobile signal is translocated from wounded sites to undamaged distal sites. This phenomenon is classified as wound-induced systemic acquired resistance (WSR). The key compound involved in this systemic signal transduction is supposed to be JA or its derivatives. Based on the kinetic study of the accumulation of JA and its derivatives responding to wounding stress, it was uncovered that JA was accumulated in undamaged systemic tissues within 0.5h after wounding and then, metabolized to JA-Ile, tuberonic acid (12-OH JA), and tuberonic acid glucoside. Attempts to recover deuterium and radio isotope labeled JA, which were fed to wounding leaves, were successfully accomplished. Therefore, it was demonstrated that JA could be transported from the damaged site to the systemic leaves.

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

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