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Yi M, Yang H, Yang S, Wang J. Overexpression of SHORT-ROOT2 transcription factor enhances the outgrowth of mature axillary buds in poplar trees. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2469-2486. [PMID: 35107566 DOI: 10.1093/jxb/erac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
SHORT-ROOT (SHR) transcription factors play important roles in asymmetric cell division and radial patterning of Arabidopsis roots. In hybrid poplar (P. tremula × P. alba clone INRA 717-1B4), PtaSHR2 was preferentially expressed in axillary buds (AXBs) and transcriptionally up-regulated during AXB maturation and activation. Overexpression of SHR2 (PtSHR2OE) induced an enhanced outgrowth of AXBs below the bud maturation point, with a simultaneous transition of an active shoot apex into an arrested terminal bud. The larger and more mature AXBs of PtSHR2OE trees revealed altered expression of genes involved in axillary meristem initiation and bud activation, as well as a higher ratio of cytokinin to auxin. To elucidate the underlying mechanism of PtSHR2OE-induced high branching, subsequent molecular and biochemical studies showed that compared with wild-type trees, decapitation induced a quicker bud outburst in PtSHR2OE trees, which could be fully inhibited by exogenous application of auxin or cytokinin biosynthesis inhibitor, but not by N-1-naphthylphthalamic acid. Our results indicated that overexpression of PtSHR2B disturbed the internal hormonal balance in AXBs by interfering with the basipetal transport of auxin, rather than causing auxin biosynthesis deficiency or auxin insensitivity, thereby releasing mature AXBs from apical dominance and promoting their outgrowth.
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Affiliation(s)
- Minglei Yi
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Heyu Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Shaohui Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jiehua Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
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Ohashi M, Ishiyama K, Kojima S, Konishi N, Sasaki K, Miyao M, Hayakawa T, Yamaya T. Outgrowth of Rice Tillers Requires Availability of Glutamine in the Basal Portions of Shoots. RICE (NEW YORK, N.Y.) 2018; 11:31. [PMID: 29744685 PMCID: PMC5943206 DOI: 10.1186/s12284-018-0225-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 04/30/2018] [Indexed: 05/06/2023]
Abstract
BACKGROUND Our previous studies concluded that metabolic disorder in the basal portions of rice shoots caused by a lack of cytosolic glutamine synthetase1;2 (GS1;2) resulted in a severe reduction in the outgrowth of tillers. Rice mutants lacking GS1;2 (gs1;2 mutants) showed a remarkable reduction in the contents of both glutamine and asparagine in the basal portions of shoots. In the current study, we attempted to reveal the mechanisms for this decrease in asparagine content using rice mutants lacking either GS1;2 or asparagine synthetase 1 (AS1). The contributions of the availability of glutamine and asparagine to the outgrowth of rice tillers were investigated. RESULTS Rice has two AS genes, and the enzymes catalyse asparagine synthesis from glutamine. In the basal portions of rice shoots, expression of OsAS1, the major species in this tissue, was reduced in gs1;2 mutants, whereas OsAS2 expression was relatively constant. OsAS1 was expressed in phloem companion cells of the nodal vascular anastomoses connected to the axillary bud vasculatures in the basal portions of wild-type shoots, whereas cell-specific expression was markedly reduced in gs1;2 mutants. OsAS1 was up-regulated significantly by NH4+ supply in the wild type but not in gs1;2 mutants. When GS reactions were inhibited by methionine sulfoximine, OsAS1 was up-regulated by glutamine but not by NH4+. The rice mutants lacking AS1 (as1 mutants) showed a decrease in asparagine content in the basal portions of shoots. However, glutamine content and tiller number were less affected by the lack of AS1. CONCLUSION These results indicate that in phloem companion cells of the nodal vascular anastomoses, asparagine synthesis is largely dependent on glutamine or its related metabolite-responsive AS1. Thus, the decrease in glutamine content caused by a lack of GS1;2 is suggested to result in low expression of OsAS1, decreasing asparagine content. However, the availability of asparagine generated from AS1 reactions is apparently less effective for the outgrowth of tillers. With respect to the tiller number and the contents of glutamine and asparagine in gs1;2 and as1 mutants, the availability of glutamine rather than asparagine in basal portions of rice shoots may be required for the outgrowth of rice tillers.
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Affiliation(s)
- Miwa Ohashi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan.
- Present Address: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Keiki Ishiyama
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
| | - Soichi Kojima
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
| | - Noriyuki Konishi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
- Present Address: Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, 710-0046, Japan
| | - Kazuhiro Sasaki
- The University of Tokyo, Graduate School of Agricultural and Life Sciences, Institute of Sustainable Agro-ecosystem Services (ISAS), 1-1-1 Midori-cho, Nishitokyo, Tokyo, 188-0002, Japan
| | - Mitsue Miyao
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
| | - Toshihiko Hayakawa
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
| | - Tomoyuki Yamaya
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-8572, Japan
- Present Address: Division for Interdisciplinary Advanced Research and Education, Tohoku University, 6-3 Aoba, Aramaki-Aza, Aoba-ku, Sendai, 980-0845, Japan
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Vega-Mas I, Pérez-Delgado CM, Marino D, Fuertes-Mendizábal T, González-Murua C, Márquez AJ, Betti M, Estavillo JM, González-Moro MB. Elevated CO2 Induces Root Defensive Mechanisms in Tomato Plants When Dealing with Ammonium Toxicity. PLANT & CELL PHYSIOLOGY 2017; 58:2112-2125. [PMID: 29059445 DOI: 10.1093/pcp/pcx146] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/20/2017] [Indexed: 05/23/2023]
Abstract
An adequate carbon supply is fundamental for plants to thrive under ammonium stress. In this work, we studied the mechanisms involved in tomato (Solanum lycopersicum L.) response to ammonium toxicity when grown under ambient or elevated CO2 conditions (400 or 800 p.p.m. CO2). Tomato roots were observed to be the primary organ dealing with ammonium nutrition. We therefore analyzed nitrogen (N) and carbon (C) metabolism in the roots, integrating the physiological response with transcriptomic regulation. Elevated levels of CO2 preferentially stimulated root growth despite the high ammonium content. The induction of anaplerotic enzymes from the tricarboxylic acid (TCA) cycle led to enhanced amino acid synthesis under ammonium nutrition. Furthermore, the root transcriptional response to ammonium toxicity was improved by CO2-enriched conditions, leading to higher expression of stress-related genes, as well as enhanced modulation of genes related to signaling, transcription, transport and hormone metabolism. Tomato roots exposed to ammonium stress also showed a defense-like transcriptional response according to the modulation of genes related to detoxification and secondary metabolism, involving principally terpenoid and phenolic compounds. These results indicate that increasing C supply allowed the co-ordinated regulation of root defense mechanisms when dealing with ammonium toxicity.
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Affiliation(s)
- Izargi Vega-Mas
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Carmen M Pérez-Delgado
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, Spain
| | - Daniel Marino
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Teresa Fuertes-Mendizábal
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Carmen González-Murua
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Antonio J Márquez
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, Spain
| | - Marco Betti
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, Spain
| | - José María Estavillo
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - María Begoña González-Moro
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
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Yabuki Y, Ohashi M, Imagawa F, Ishiyama K, Beier MP, Konishi N, Umetsu-Ohashi T, Hayakawa T, Yamaya T, Kojima S. A temporal and spatial contribution of asparaginase to asparagine catabolism during development of rice grains. RICE (NEW YORK, N.Y.) 2017; 10:3. [PMID: 28124210 PMCID: PMC5267587 DOI: 10.1186/s12284-017-0143-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/19/2017] [Indexed: 05/08/2023]
Abstract
BACKGROUND Asparagine is one of the most dominant organic nitrogen compounds in phloem and xylem sap in a wide range of plant species. Asparaginase (ASNase; EC, 3.5.1.1) catabolizes asparagine into aspartate and ammonium; therefore, it is suggested to play a key role in asparagine metabolism within legume sink organs. However, the metabolic fate of asparagine in source and sink organs during rice seed production remains to be elucidated. Therefore, the main objective of this study is to investigate the asparagine metabolism in a temporal and spatial manner during rice seed production. RESULTS For this purpose, the expression of genes involved in asparagine catabolism, such as asparaginase1 (OsASNase1) and 2 (OsASNase2), were quantitatively measured, and contents of asparagine, aspartate and ammonium ions were determined in sink and source organs during spikelet ripening. Quantitative real-time PCR and in situ localization studies determined that OsASNase2 is expressed in the dorsal vascular bundles and nucellar projection of developing grains, as well as in mesophyll and phloem companion cells of senescent flag leaves. Amino acid measurements revealed that the aspartate concentration is higher than asparagine in both source and sink organs. CONCLUSION This work suggests that asparaginase dependent asparagine catabolism occurred not only in sink but also in source organs.
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Affiliation(s)
- Yui Yabuki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Miwa Ohashi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Fumi Imagawa
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Keiki Ishiyama
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Marcel Pascal Beier
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Noriyuki Konishi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Toshiko Umetsu-Ohashi
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Toshihiko Hayakawa
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Tomoyuki Yamaya
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
| | - Soichi Kojima
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Sendai, 9800845 Japan
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Ohashi M, Ishiyama K, Kojima S, Kojima M, Sakakibara H, Yamaya T, Hayakawa T. Lack of Cytosolic Glutamine Synthetase1;2 Activity Reduces Nitrogen-Dependent Biosynthesis of Cytokinin Required for Axillary Bud Outgrowth in Rice Seedlings. PLANT & CELL PHYSIOLOGY 2017; 58:679-690. [PMID: 28186255 DOI: 10.1093/pcp/pcx022] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 02/01/2017] [Indexed: 05/05/2023]
Abstract
A mutation abolishing cytosolic glutamine synthetase1;2 (GS1;2) activity impairs assimilation of ammonium into glutamine in both roots and basal portions of shoots, and severely decreases axillary bud outgrowth (tillering) in mutant rice seedlings. Although the gs1;2 mutant phenotype is independent of strigolactone, which inhibits tillering, it also demonstrates glutamine- or related metabolite-responsive biosynthesis of cytokinin (CK), which promotes tillering. Here, we examined the connection between GS1;2 and CK biosynthesis during tillering, focusing on basal portions of the shoots as well as apical and axillary bud meristems in the gs1;2 mutant. Despite a sufficient ammonium supply, decreases in precursor CK contents and a decrease in ammonium assimilation into glutamine were observed in basal portions of mutant shoots. Reintroducing expression of OsGS1;2 cDNA driven by its own promoter restored precursor CK contents and ammonium assimilation to wild-type levels. In basal portions of the shoots, glutamine-responsive adenosine phosphate-isopentenyltransferase4 (OsIPT4), which is also predominant in rice roots, was the predominant isogene for IPT, which synthesizes CK. Cell-specific expression of OsIPT4 in phloem companion cells in nodal vascular anastomoses connected to the axillary bud vasculature also decreased in the gs1;2 mutant. Expression of CK-responsive type-A response regulator genes as local indicators of active CKs was also abolished in the axillary bud meristem of the mutant. These results suggest that the lack of GS1;2 activity decreased levels of glutamine or a related metabolite required for CK biosynthesis, causing a deficiency in active CK in the axillary bud meristem necessary for tillering.
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Affiliation(s)
- Miwa Ohashi
- Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Japan
| | - Keiki Ishiyama
- Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Japan
| | - Soichi Kojima
- Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Japan
| | - Mikiko Kojima
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
| | - Tomoyuki Yamaya
- Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Japan
- University Research Administration Center, Tohoku University, Aoba, Sendai, Japan
- Division for Interdisciplinary Advanced Research and Education, Tohoku University, Aoba, Sendai, Japan
| | - Toshihiko Hayakawa
- Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Japan
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Proteome changes induced by Pyrenophora tritici-repentis ToxA in both insensitive and sensitive wheat indicate senescence-like signaling. Proteome Sci 2015; 13:3. [PMID: 25663824 PMCID: PMC4320625 DOI: 10.1186/s12953-014-0060-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 12/23/2014] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Pyrenophora tritici-repentis is a phytopathogenic fungus which causes tan spot on wheat. Some races of P. tritici-repentis produce host-specific toxins which present symptoms of chlorosis or necrosis on susceptible wheat cultivars. One such toxin is Ptr ToxA, which enters mesophyll cells through a putative toxin-receptor and localizes with chloroplasts, ultimately causing damage and necrosis on leaves. These symptoms can occur even in the absence of the pathogen. Insensitive cultivars lack the receptor and Ptr ToxA cannot enter cells. The molecular mechanisms surrounding this plant-pathogen interaction are still largely unknown, although some details have begun to emerge. RESULTS Using 2-D electrophoresis, fifteen protein changes were identified reproducibly in the leaf proteomes of a sensitive and an insensitive cultivar over three days after inoculation of purified Ptr ToxA. Functional analysis of the proteins indicated that senescence signals may be induced in the sensitive cultivar. In the insensitive cultivar proteins involved in some features of senescence inhibition were seen. Complementary responses at the biochemical level may be actively promoting a localized senescence-like response in sensitive wheat cultivars whilst actively inhibiting this response in insensitive cultivars. CONCLUSION This is the first report of a biochemical response in an insensitive cultivar in this plant-pathogen interaction. Findings support the involvement of ethylene, and the activation of complementary pathways in sensitive versus insensitive wheat cultivars responding to Ptr ToxA. The nature of the system permits using purified toxin to mimic disease, which eliminates the pathogen proteome and ensures a synchronous response in inoculated leaves.
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Ohashi M, Ishiyama K, Kusano M, Fukushima A, Kojima S, Hanada A, Kanno K, Hayakawa T, Seto Y, Kyozuka J, Yamaguchi S, Yamaya T. Lack of cytosolic glutamine synthetase1;2 in vascular tissues of axillary buds causes severe reduction in their outgrowth and disorder of metabolic balance in rice seedlings. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:347-56. [PMID: 25429996 DOI: 10.1111/tpj.12731] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 11/03/2014] [Accepted: 11/19/2014] [Indexed: 05/20/2023]
Abstract
The development and elongation of active tillers in rice was severely reduced by a lack of cytosolic glutamine synthetase1;2 (GS1;2), and, to a lesser extent, lack of NADH-glutamate synthase1 in knockout mutants. In situ hybridization using the basal part of wild-type seedlings clearly showed that expression of OsGS1;2 was detected in the phloem companion cells of the nodal vascular anastomoses and large vascular bundles of axillary buds. Accumulation of lignin, visualized using phloroglucin HCl, was also observed in these tissues. The lack of GS1;2 resulted in reduced accumulation of lignin. Re-introduction into the mutants of OsGS1;2 cDNA under the control of its own promoter successfully restored the outgrowth of tillers and lignin deposition to wild-type levels. Transcriptomic analysis using a 5 mm basal region of rice shoots showed that the GS1;2 mutants accumulated reduced amounts of mRNAs for carbon and nitrogen metabolism, including C1 unit transfer in lignin synthesis. Although a high content of strigolactone in rice roots is known to reduce active tiller number, the reduction of outgrowth of axillary buds observed in the GS1;2 mutants was independent of the level of strigolactone. Thus metabolic disorder caused by the lack of GS1;2 resulted in a severe reduction in the outgrowth of axillary buds and lignin deposition.
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Affiliation(s)
- Miwa Ohashi
- Graduate School of Agriculture Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan
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Seifi HS, Curvers K, De Vleesschauwer D, Delaere I, Aziz A, Höfte M. Concurrent overactivation of the cytosolic glutamine synthetase and the GABA shunt in the ABA-deficient sitiens mutant of tomato leads to resistance against Botrytis cinerea. THE NEW PHYTOLOGIST 2013; 199:490-504. [PMID: 23627463 DOI: 10.1111/nph.12283] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 03/14/2013] [Indexed: 05/22/2023]
Abstract
Deficiency of abscisic acid (ABA) in the sitiens mutant of tomato (Solanum lycopersicum) culminates in increased resistance to Botrytis cinerea through a rapid epidermal hypersensitive response (HR) and associated phenylpropanoid pathway-derived cell wall fortifications. This study focused on understanding the role of primary carbon : nitrogen (C : N) metabolism in the resistance response of sitiens to B. cinerea. How alterations in C : N metabolism are linked with the HR-mediated epidermal arrest of the pathogen has been also investigated. Temporal alterations in the γ-aminobutyric acid (GABA) shunt, glutamine synthetase/glutamate synthase (GS/GOGAT) cycle and phenylpropanoid pathway were transcriptionally, enzymatically and metabolically monitored in both wild-type and sitiens plants. Virus-induced gene silencing, microscopic analyses and pharmacological assays were used to further confirm the data. Our results on the sitiens-B. cinerea interaction favor a model in which cell viability in the cells surrounding the invaded tissue is maintained by a constant replenishment of the tricarboxylic acid (TCA) cycle through overactivation of the GS/GOGAT cycle and the GABA shunt, resulting in resistance through both tightly controlling the defense-associated HR and slowing down the pathogen-induced senescence. Collectively, this study shows that maintaining cell viability via alterations in host C : N metabolism plays a vital role in the resistance response against necrotrophic pathogens.
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Affiliation(s)
- Hamed Soren Seifi
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Katrien Curvers
- Laboratory of Applied Molecular Genetics, Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - David De Vleesschauwer
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Ilse Delaere
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Aziz Aziz
- Laboratory of SDRP - URVVC EA 4707, University of Reims, Campus Moulin de la Housse, 51687, Reims Cedex 2, France
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
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Sabater B, Martín M. Hypothesis: increase of the ratio singlet oxygen plus superoxide radical to hydrogen peroxide changes stress defense response to programmed leaf death. FRONTIERS IN PLANT SCIENCE 2013; 4:479. [PMID: 24324479 PMCID: PMC3839260 DOI: 10.3389/fpls.2013.00479] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/05/2013] [Indexed: 05/07/2023]
Abstract
The level of reactive oxygen species (ROS) increases under different stresses and, by destroying cellular components, may cause cell death. In addition, ROS are part of the complex network of transduction signals that induce defense reactions against stress or, alternatively, trigger programmed cell death, and key questions are the levels of each ROS that, respectively determine defense and death responses of the cell. The answer to those questions is difficult because there are several patterns of cell death that frequently appear mixed and are hardly distinguishable. Moreover, although considerable progresses have been achieved in the determination of the levels of specific ROS, critical questions remain on the ROS level in specific cell compartments. By considering chloroplasts as the main source of ROS in photosynthetic tissues at light, a comparison of the levels in stress and senescence of the chloroplastic activities involved in the generation and scavenging of ROS suggests plausible differences in the levels of specific ROS between stress defense and death. In effect, the three activities of the chlororespiratory chain increase similarly in stress defense response. However, in senescence, superoxide dismutase (SOD), that converts superoxide anion radical ([Formula: see text]) to hydrogen peroxide (H2O2,) decreases, while the thylakoid Ndh complex, that favors the generation of singlet oxygen ((1)O2) and [Formula: see text], and peroxidase (PX), that consumes H2O2, increase. The obvious inference is that, in respect to defense response, the ratio ((1)O2 plus [Formula: see text])/H2O2 is increased in the senescence previous to cell death. We hypothesize that the different ROS ratios, probably through changes in the jasmonic acid/H2O2 ratio, could determine the activation of the defense network or the death network response of the cell.
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Affiliation(s)
- Bartolomé Sabater
- *Correspondence: Bartolomé Sabater, Departamento de Ciencias de la Vida (Fisiología Vegetal), Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain e-mail:
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Castro-Rodríguez V, García-Gutiérrez A, Canales J, Avila C, Kirby EG, Cánovas FM. The glutamine synthetase gene family in Populus. BMC PLANT BIOLOGY 2011; 11:119. [PMID: 21867507 PMCID: PMC3224142 DOI: 10.1186/1471-2229-11-119] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 08/25/2011] [Indexed: 05/20/2023]
Abstract
BACKGROUND Glutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming) is a key enzyme in ammonium assimilation and metabolism of higher plants. The current work was undertaken to develop a more comprehensive understanding of molecular and biochemical features of GS gene family in poplar, and to characterize the developmental regulation of GS expression in various tissues and at various times during the poplar perennial growth. RESULTS The GS gene family consists of 8 different genes exhibiting all structural and regulatory elements consistent with their roles as functional genes. Our results indicate that the family members are organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1) and 1 which codes for the choroplastic GS isoform (GS2). Our analysis shows that Populus trichocarpa is the first plant species in which it was observed the complete GS family duplicated. Detailed expression analyses have revealed specific spatial and seasonal patterns of GS expression in poplar. These data provide insights into the metabolic function of GS isoforms in poplar and pave the way for future functional studies. CONCLUSIONS Our data suggest that GS duplicates could have been retained in order to increase the amount of enzyme in a particular cell type. This possibility could contribute to the homeostasis of nitrogen metabolism in functions associated to changes in glutamine-derived metabolic products. The presence of duplicated GS genes in poplar could also contribute to diversification of the enzymatic properties for a particular GS isoform through the assembly of GS polypeptides into homo oligomeric and/or hetero oligomeric holoenzymes in specific cell types.
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Affiliation(s)
- Vanessa Castro-Rodríguez
- Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Universidad de Málaga, 29071-Málaga, Spain
| | - Angel García-Gutiérrez
- Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Universidad de Málaga, 29071-Málaga, Spain
| | - Javier Canales
- Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Universidad de Málaga, 29071-Málaga, Spain
| | - Concepción Avila
- Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Universidad de Málaga, 29071-Málaga, Spain
| | - Edward G Kirby
- Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA
| | - Francisco M Cánovas
- Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Universidad de Málaga, 29071-Málaga, Spain
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11
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Hsieh LS, Ma GJ, Yang CC, Lee PD. Cloning, expression, site-directed mutagenesis and immunolocalization of phenylalanine ammonia-lyase in Bambusa oldhamii. PHYTOCHEMISTRY 2010; 71:1999-2009. [PMID: 21035152 DOI: 10.1016/j.phytochem.2010.09.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 08/30/2010] [Accepted: 09/27/2010] [Indexed: 05/30/2023]
Abstract
Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) from green bamboo was isolated and cloned from the shell of Bambusa oldhamii. The K(m) of bamboo shell PAL for L-Phe was 476 μM, and the molecular mass of native PAL was estimated as 275 kDa and the molecular mass of a subunit was about 76 kDa, indicating that PAL from bamboo also exists as a tetramer. The optimum temperature for PAL activity was 50°C and the optimal pH 9.0. The identity of the purified bamboo shell PAL was confirmed using Q-TOF tandem MS/MS de novo sequencing. Four PAL genes, designated as BoPAL1 to BoPAL4, were cloned from B. oldhamii. The open reading frames of BoPAL3 and BoPAL4 were 2142 and 2106 bp in size, respectively: BoPAL2-4 contained one intron and two exons, but no intron was found in BoPAL1. BoPAL4 expressed in Escherichia coli possessed both PAL and tyrosine ammonia-lyase activities. While recombinant wild-type PAL proteins had similar biochemical properties to the native bamboo shell PAL, both site-directed mutagenesis of BoPAL1 F133H and BoPAL2 F134H, respectively, showed decreased k(cat)/K(m) values toward L-Phe, whereas BoPAL2 F134H showed a slightly increased k(cat)/K(m) value toward L-Tyr. These data suggest other residues largely control Phe/Tyr substrate specificity. An antibody raised against the purified shell PAL was generated for histochemical studies. In bamboo shell and branch shoots, PAL was localized primarily in sclerenchyma cells.
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Affiliation(s)
- Lu-Sheng Hsieh
- Institute of Microbiology and Biochemistry, National Taiwan University, 1 Sec. 4, Roosevelt Road, Taipei, Taiwan
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12
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Reverse genetics approach to characterize a function of NADH-glutamate synthase1 in rice plants. Amino Acids 2010; 39:1003-12. [PMID: 20213442 DOI: 10.1007/s00726-010-0531-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 02/12/2010] [Indexed: 10/19/2022]
Abstract
Rice plants grown in anaerobic paddy soil prefer to use ammonium ion as an inorganic nitrogen source for their growth. The ammonium ions are assimilated by the coupled reaction of glutamine synthetase (GS) and glutamate synthase (GOGAT). In rice, there is a small gene family for GOGAT: there are two NADH-dependent types and one ferredoxin (Fd)-dependent type. Fd-GOGAT is important in the re-assimilation of photorespiratorily generated ammonium ions in chloroplasts. Although cell-type and age-dependent expression of two NADH-GOGAT genes has been well characterized, metabolic function of individual gene product is not fully understood. Reverse genetics approach is a direct way to characterize functions of isoenzymes. We have isolated a knockout rice mutant lacking NADH-dependent glutamate synthase1 (NADH-GOGAT1) and our studies show that this isoenzyme is important for primary ammonium assimilation in roots at the seedling stage. NADH-GOGAT1 is also important in the development of active tiller number, when the mutant was grown in paddy field until the harvest. Expression of NADH-GOGAT2 and Fd-GOGAT in the mutant was identical with that in wild-type, suggesting that these GOGATs are not able to compensate for NADH-GOGAT1 function.
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13
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Albinsky D, Kusano M, Higuchi M, Hayashi N, Kobayashi M, Fukushima A, Mori M, Ichikawa T, Matsui K, Kuroda H, Horii Y, Tsumoto Y, Sakakibara H, Hirochika H, Matsui M, Saito K. Metabolomic screening applied to rice FOX Arabidopsis lines leads to the identification of a gene-changing nitrogen metabolism. MOLECULAR PLANT 2010; 3:125-42. [PMID: 20085895 DOI: 10.1093/mp/ssp069] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plant metabolomics developed as a powerful tool to examine gene functions and to gain deeper insight into the physiology of the plant cell. In this study, we screened Arabidopsis lines overexpressing rice full-length (FL) cDNAs (rice FOX Arabidopsis lines) using a gas chromatography-time-of-flight mass spectrometry (GC-TOF/MS)-based technique to identify rice genes that caused metabolic changes. This screening system allows fast and reliable identification of candidate lines showing altered metabolite profiles. We performed metabolomic and transcriptomic analysis of a rice FOX Arabidopsis line that harbored the FL cDNA of the rice ortholog of the Lateral Organ Boundaries (LOB) Domain (LBD)/Asymmetric Leaves2-like (ASL) gene of Arabidopsis, At-LBD37/ASL39. The investigated rice FOX Arabidopsis line showed prominent changes in the levels of metabolites related to nitrogen metabolism. The transcriptomic data as well as the results from the metabolite analysis of the Arabidopsis At-LBD37/ASL39-overexpressor plants were consistent with these findings. Furthermore, the metabolomic and transcriptomic analysis of the Os-LBD37/ASL39-overexpressing rice plants indicated that Os-LBD37/ASL39 is associated with processes related to nitrogen metabolism in rice. Thus, the combination of a metabolomics-based screening method and a gain-of-function approach is useful for rapid characterization of novel genes in both Arabidopsis and rice.
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14
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Sato K, Nishikubo N, Mashino Y, Yoshitomi K, Zhou J, Kajita S, Katayama Y. Immunohistochemical localization of enzymes that catalyze the long sequential pathways of lignin biosynthesis during differentiation of secondary xylem tissues of hybrid aspen (Populus sieboldii x Populus grandidentata). TREE PHYSIOLOGY 2009; 29:1599-1606. [PMID: 19910325 DOI: 10.1093/treephys/tpp069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have investigated the spatial localization of enzymes that catalyze the sequential pathways of lignin biosynthesis in developing secondary xylem tissues of hybrid aspen (Populus sieboldii Miq. x Populus grandidentata Michx.) using immunohistochemical techniques. The enzymes phenylalanine ammonia-lyase, caffeic acid 3-O-methyltransferase and 4-coumarate:CoA ligase in the common phenylpropanoid pathway, cinnamyl-alcohol dehydrogenase (CAD) and peroxidase in the specific lignin pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAHPS) in the shikimate pathway and glutamine synthetase (GS) in the nitrogen reassimilation system were abundantly localized in the 6th to 9th wood fibers away from cambium; these wood fibers are likely undergoing the most intense lignification. Only weak immunolabeling of enzymes involved in the general phenylpropanoid and specific lignin pathways was detected in the cells near the cambium; lignification of these cells has likely been initiated after primary cell wall formation. In contrast, distinct localization of DAHPS and GS was observed around the cambium, which may be involved not only in lignin biosynthesis, but also in amino acid and protein synthesis, which are essential for cell survival. Our observations suggest that co-localization of enzymes related to the sequential shikimate, general phenylpropanoid and specific lignin branch pathways and to the nitrogen recycling system is associated with cell wall lignification of wood fibers during secondary xylem development.
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Affiliation(s)
- Kanna Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
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15
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Bernard SM, Habash DZ. The importance of cytosolic glutamine synthetase in nitrogen assimilation and recycling. THE NEW PHYTOLOGIST 2009; 182:608-620. [PMID: 19422547 DOI: 10.1111/j.1469-8137.2009.02823.x] [Citation(s) in RCA: 285] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Glutamine synthetase assimilates ammonium into amino acids, thus it is a key enzyme for nitrogen metabolism. The cytosolic isoenzymes of glutamine synthetase assimilate ammonium derived from primary nitrogen uptake and from various internal nitrogen recycling pathways. In this way, cytosolic glutamine synthetase is crucial for the remobilization of protein-derived nitrogen. Cytosolic glutamine synthetase is encoded by a small family of genes that are well conserved across plant species. Members of the cytosolic glutamine synthetase gene family are regulated in response to plant nitrogen status, as well as to environmental cues, such as nitrogen availability and biotic/abiotic stresses. The complex regulation of cytosolic glutamine synthetase at the transcriptional to post-translational levels is key to the establishment of a specific physiological role for each isoenzyme. The diverse physiological roles of cytosolic glutamine synthetase isoenzymes are important in relation to current agricultural and ecological issues.
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Affiliation(s)
- Stéphanie M Bernard
- Earth Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - Dimah Z Habash
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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16
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Bernard SM, Møller ALB, Dionisio G, Kichey T, Jahn TP, Dubois F, Baudo M, Lopes MS, Tercé-Laforgue T, Foyer CH, Parry MAJ, Forde BG, Araus JL, Hirel B, Schjoerring JK, Habash DZ. Gene expression, cellular localisation and function of glutamine synthetase isozymes in wheat (Triticum aestivum L.). PLANT MOLECULAR BIOLOGY 2008; 67:89-105. [PMID: 18288574 DOI: 10.1007/s11103-008-9303-y] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 01/28/2008] [Indexed: 05/25/2023]
Abstract
We present the first cloning and study of glutamine synthetase (GS) genes in wheat (Triticum aestivum L.). Based on sequence analysis, phylogenetic studies and mapping data, ten GS sequences were classified into four sub-families: GS2 (a, b and c), GS1 (a, b and c), GSr (1 and 2) and GSe (1 and 2). Phylogenetic analysis showed that the wheat GS sub-families together with the GS genes from other monocotyledonous species form four distinct clades. Immunolocalisation studies in leaves, stems and rachis in plants at flowering showed GS protein to be present in parenchyma, phloem companion and perifascicular sheath cells. In situ localisation confirmed that GS1 transcripts were present in the perifascicular sheath cells whilst those for GSr were confined to the vascular cells. Studies of the expression and protein profiles showed that all GS sub-families were differentially expressed in the leaves, peduncle, glumes and roots. Expression of GS genes in leaves was developmentally regulated, with both GS2 and GS1 assimilating or recycling ammonia in leaves during the period of grain development and filling. During leaf senescence the cytosolic isozymes, GS1 and GSr, were the predominant forms, suggesting major roles in assimilating ammonia during the critical phases of remobilisation of nitrogen to the grain. A preliminary analysis of three different wheat genotypes showed that the ratio of leaf GS2 protein to GS1 protein was variable. Use of this genetic variation should inform future efforts to modulate this enzyme for pre-breeding efforts to improve nitrogen use in wheat.
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Affiliation(s)
- Stéphanie M Bernard
- Plant Science Department, Centre for Crop Genetic Improvement, Rothamsted Research, Harpenden, Hertfordshire, UK
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17
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Hung KT, Kao CH. The participation of hydrogen peroxide in methyl jasmonate-induced NH(4)(+) accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:1469-79. [PMID: 17215059 DOI: 10.1016/j.jplph.2006.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/14/2006] [Accepted: 10/17/2006] [Indexed: 05/13/2023]
Abstract
Ammonium is a central intermediate in the nitrogen metabolism of plants. We have previously shown that methyl jasmonate (MJ) not only increases the content of H(2)O(2), but also causes NH(4)(+) accumulation in rice leaves. More recently, H(2)O(2) is thought to constitute a general signal molecule participating in the recognition of and the response to stress factors. In this study, we examined the role of H(2)O(2) as a link between MJ and subsequent NH(4)(+) accumulation in detached rice leaves. MJ treatment resulted in an accumulation of NH(4)(+) in detached rice leaves, which was preceded by a decrease in the activity of glutamine synthetase (GS) and an increase in the specific activities of protease and phenylalanine ammonia-lyase (PAL). GS, PAL, and protease appear to be the enzymes responsible for the accumulation of NH(4)(+) in MJ-treated detached rice leaves. Dimethylthiourea (DMTU), a chemical trap for H(2)O(2), was observed to be effective in inhibiting MJ-induced NH(4)(+) accumulation in detached rice leaves. Scavengers of free radicals (sodium benzoate, SB, and glutathione, GSH), nitric oxide donor (N-tert-butyl-alpha-phenylnitrone, PBN), the inhibitors of NADPH oxidase (diphenyleneiodonium chloride, DPI, and imidazole, IMD), and inhibitors of phosphatidylinositol 3-kinase (wortmannin, WM, and LY 294002, LY), which have previously been shown to prevent MJ-induced H(2)O(2) production in detached rice leaves, inhibited MJ-induced NH(4)(+) accumulation. Similarly, changes in enzymes responsible for NH(4)(+) accumulation induced by MJ were observed to be inhibited by DMTU, SB, GSH, PBN DPI, IMD, WM, or LY. Seedlings of rice cultivar Taichung Native 1 (TN1) are jasmonic acid (JA)-sensitive and those of cultivar Tainung 67 (TNG67) are JA-insensitive. On treatment with JA, H(2)O(2) accumulated in the leaves of TN1 seedlings but not in the leaves of TNG67. Ethylene action inhibitor, silver thiosulfate, was observed to inhibit MJ- and abscisic acid-induced accumulation of NH(4)(+) and changes in enzymes responsible for NH(4)(+) accumulation in detached rice leaves, suggesting that the action of MJ and ABA is ethylene dependent.
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Affiliation(s)
- Kuo Tung Hung
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China
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18
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Yu CC, Hung KT, Kao CH. Nitric oxide reduces Cu toxicity and Cu-induced NH4+ accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1319-30. [PMID: 16425450 DOI: 10.1016/j.jplph.2005.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nitric oxide (NO) is a highly reactive, membrane-permeable free radical, which has recently emerged as an important antioxidant. Here we investigated the protective effect of NO against the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4 (10mmol L(-1)). It was found that free radical scavengers (sodium benzoate, thiourea, and reduced glutathione) reduced the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4. NO donor sodium nitroprusside (SNP) was also effective in reducing CuSO4-induced toxicity and NH4+ accumulation in rice leaves. The protective effect of SNP on the toxicity and NH4+ accumulation can be reversed by 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, suggesting that the protective effect of SNP is attributable to NO released. Results obtained in the present study suggest that reduction of CuSO4-induced toxicity and NH4+ accumulation by SNP is most likely mediated through its ability to scavenge active oxygen species.
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Affiliation(s)
- Chia Chi Yu
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, China
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19
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Mase K, Sato K, Nakano Y, Nishikubo N, Tsuboi Y, Zhou J, Kitano H, Katayama Y. The ectopic expression of phenylalanine ammonia lyase with ectopic accumulation of polysaccharide-linked hydroxycinnamoyl esters in internode parenchyma of rice mutant Fukei 71. PLANT CELL REPORTS 2005; 24:487-493. [PMID: 15838683 DOI: 10.1007/s00299-005-0960-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 01/30/2005] [Accepted: 03/07/2005] [Indexed: 05/24/2023]
Abstract
Both polysaccharide-linked hydroxycinnamoyl esters (PHEs) and lignin are biosynthesized via the phenylpropanoid pathway. In the abnormal internode parenchyma of the rice (Oryza sativa L.) mutant Fukei 71, which has a defective recessive gene (d50), the biosynthesis of lignin and PHEs differs. . The polysaccharide-linked ferulate and p-coumarate have been shown to accumulate to high levels in the irregularly shaped and collapsed internode parenchyma cells of Fukei 71 without an accompanying overaccumulation of lignin as a result of the defective d50 gene. In the present study we demonstrated that in this abnormal parenchyma tissue of Fukei 71 the expression of phenylalanine ammonia lyase (PAL) and glutamine synthetase (GS) were ectopically induced with the ectopic accumulation of PHEs, suggesting that the d50 gene may play a role as a controlling element in the biosynthesis of PHEs during cell-wall formation in the grasses.
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Affiliation(s)
- Kohei Mase
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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20
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Hung KT, Kao CH. Hydrogen peroxide is required for abscisic acid-induced NH4+ accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1022-9. [PMID: 16173463 DOI: 10.1016/j.jplph.2004.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The role of H2O2 in abscisic acid (ABA)-induced NH4+ accumulation in rice leaves was investigated. ABA treatment resulted in an accumulation of NH4+ in rice leaves, which was preceded by a decrease in the activity of glutamine synthetase (GS) and an increase in the specific activities of protease and phenylalanine ammonia-lyase (PAL). GS, PAL, and protease seem to be the enzymes responsible for the accumulation of NH4+ in ABA-treated rice leaves. Dimethylthiourea (DMTU), a chemical trap for H2O2, was observed to be effective in inhibiting ABA-induced accumulation of NH4+ in rice Leaves. Inhibitors of NADPH oxidase, diphenyleneiodonium chloride (DPI) and imidazole (IMD), and nitric oxide donor (N-tert-butyl-alpha-phenylnitrone, PBN), which have previously been shown to prevent ABA-induced increase in H2O2 contents in rice leaves, inhibited ABA-induced increase in the content of NH4+. Similarly, the changes of enzymes responsible for NH4+ accumulation induced by ABA were observed to be inhibited by DMTU, DPI, IMD, and PBN. Exogenous application of H2O2 was found to increase NH4+ content, decrease GS activity, and increase protease and PAL-specific activities in rice leaves. Our results suggest that H2O2 is involved in ABA-induced NH4+ accumulation in rice leaves.
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Affiliation(s)
- Kuo Tung Hung
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China
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21
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Hsu YT, Kao CH. Abscisic acid accumulation and cadmium tolerance in rice seedlings. PHYSIOLOGIA PLANTARUM 2005; 124:71-80. [PMID: 0 DOI: 10.1111/j.1399-3054.2005.00490.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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22
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Tobias CM, Chow EK. Structure of the cinnamyl-alcohol dehydrogenase gene family in rice and promoter activity of a member associated with lignification. PLANTA 2005; 220:678-688. [PMID: 15452707 DOI: 10.1007/s00425-004-1385-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Accepted: 08/17/2004] [Indexed: 05/24/2023]
Abstract
Analysis of lignification in rice has been facilitated by the availability of the recently completed rice genome sequence, and rice will serve as an important model for understanding the relationship of grass lignin composition to cell wall digestibility. Cinnamyl-alcohol dehydrogenase (CAD) is an enzyme important in lignin biosynthesis. The rice genome contains 12 distinct genes present at nine different loci that encode products with significant similarity to CAD. The rice gene family is diverse with respect to other angiosperm and gymnosperm CAD genes isolated to date and includes one member (OsCAD6) that contains a peroxisomal targeting signal and is substantially diverged relative to other family members. Four closely related family members (OsCAD8A-D) are present at the same locus and represent the product of a localized gene duplication and inversion. Promoter-reporter gene fusions to OsCAD2, an orthologue of the CAD gene present at the bm1 (brown midrib 1) locus of maize, reveal that in rice expression is associated with vascular tissue in aerial parts of the plant and is correlated with the onset of lignification. In root tissue, expression is primarily in the cortical parenchyma adjacent to the exodermis and in vascular tissue.
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Affiliation(s)
- Christian M Tobias
- Agricultural Research Service, Western Regional Research Center, United States Department of Agriculture, 800 Buchanan Street, Albany, CA 94710, USA.
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23
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Ishiyama K, Inoue E, Tabuchi M, Yamaya T, Takahashi H. Biochemical background and compartmentalized functions of cytosolic glutamine synthetase for active ammonium assimilation in rice roots. PLANT & CELL PHYSIOLOGY 2004; 45:1640-7. [PMID: 15574840 DOI: 10.1093/pcp/pch190] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Rice plants in paddy fields prefer to utilize ammonium as a major nitrogen source. Glutamine synthetase (GS) serves for assimilation of ammonium in rice root, and ameliorates the toxic effect of ammonium excess. Among the three isoenzymes of the cytosolic GS1 gene family in rice, OsGLN1;1 and OsGLN1;2 were abundantly expressed in roots. Analysis of the purified enzymes showed that OsGLN1;1 and OsGLN1;2 can be classified into high-affinity subtypes with relatively high V(max) values, as compared with the major high-affinity isoenzyme, GLN1;1, in Arabidopsis. Low-affinity forms of GS1 comparable to those in Arabidopsis (GLN1;2 and GLN1;3) were absent in rice roots. The OsGLN1;1 and OsGLN1;2 transcripts showed reciprocal responses to ammonium supply in the surface cell layers of roots. OsGLN1;1 accumulated in dermatogen, epidermis and exodermis under nitrogen-limited condition. By contrast, OsGLN1;2 was abundantly expressed in the same cell layers under nitrogen-sufficient conditions, replenishing the loss of OsGLN1;1 following ammonium treatment. Within the central cylinder of elongating zone, OsGLN1;1 and OsGLN1;2 were both induced by ammonium, which was distinguishable from the response observed in the surface cell layers. The high-capacity Gln synthetic activities of OsGLN1;1 and OsGLN1;2 facilitate active ammonium assimilation in specific cell types in rice roots.
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Affiliation(s)
- Keiki Ishiyama
- RIKEN Plant Science Center, 1-7-22 Suehiro, Tsurumi-ku, Yokohama, 230-0045 Japan
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Ralph J, Guillaumie S, Grabber JH, Lapierre C, Barrière Y. Genetic and molecular basis of grass cell-wall biosynthesis and degradability. III. Towards a forage grass ideotype. C R Biol 2004; 327:467-79. [PMID: 15255477 DOI: 10.1016/j.crvi.2004.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Lignification of cell walls is the major factor controlling the digestibility of forage grasses. Thus far, from QTL analysis, about 15 locations involved in cell-wall lignification or digestibility have been identified in the maize genome, many of which colocalise with QTLs involved in corn borer susceptibility. Genetic diversity for enhancing cell-wall digestibility in maize must be identified in novel germplasm, but genetic engineering is also a relevant way both to design specific cell-wall characteristics for improved digestibility and to identify genes involved in these traits for further discovery of alleles of interest in grass germplasm.
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Affiliation(s)
- John Ralph
- US Dairy Forage Research Center, USDA-Agricultural Research Service, 1925 Linden Drive West, Madison, WI 53706, USA
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25
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Gómez-Maldonado J, Avila C, Torre F, Cañas R, Cánovas FM, Campbell MM. Functional interactions between a glutamine synthetase promoter and MYB proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 39:513-26. [PMID: 15272871 DOI: 10.1111/j.1365-313x.2004.02153.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In Scots pine (Pinus sylvestris), ammonium assimilation is catalysed by glutamine synthetase (GS) [EC 6.3.1.2], which is encoded by two genes, PsGS1a and PsGS1b. PsGS1b is expressed in the vascular tissue throughout the plant body, where it is believed to play a role in recycling ammonium released by various facets of metabolism. The mechanisms that may underpin the transcriptional regulation of PsGS1b were explored. The PsGS1b promoter contains a region that is enriched in previously characterized cis-acting elements, known as AC elements. Pine nuclear proteins bound these AC element-rich regions in a tissue-specific manner. As previous experiments had shown that R2R3-MYB transcription factors could interact with AC elements, the capacity of the AC elements in the PsGS1b promoter to interact with MYB proteins was examined. Two MYB proteins from loblolly pine (Pinus taeda), PtMYB1 and PtMYB4, bound to the PsGS1b promoter were able to activate transcription from this promoter in yeast, arabidopsis and pine cells. Immunolocalization experiments revealed that the two MYB proteins were most abundant in cells previously shown to accumulate PsGS1b transcripts. Immunoprecipitation analysis and supershift electrophoretic mobility shift assays implicated these same two proteins in the formation of complexes between pine nuclear extracts and the PsGS1b promoter. Given that these MYB proteins were previously shown to have the capacity to activate gene expression related to lignin biosynthesis, we hypothesize that they may function to co-regulate lignification, a process that places significant demands on nitrogen recycling, and GS, the major enzyme involved in the nitrogen recycling pathway.
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Affiliation(s)
- Josefa Gómez-Maldonado
- Biología Molecular y Bioquímica, Instituto Andaluz de Biotencología, Unidad Asociada UMA-CSIC, Universidad de Málaga, Campus Universitairo de Teatinos, E-29071 Málaga, Spain
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Ishiyama K, Inoue E, Watanabe-Takahashi A, Obara M, Yamaya T, Takahashi H. Kinetic properties and ammonium-dependent regulation of cytosolic isoenzymes of glutamine synthetase in Arabidopsis. J Biol Chem 2004; 279:16598-605. [PMID: 14757761 DOI: 10.1074/jbc.m313710200] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamine synthetase (GS; EC 6.3.1.2) is a key enzyme of nitrogen assimilation, catalyzing the synthesis of glutamine from ammonium and glutamate. In Arabidopsis, cytosolic GS (GS1) was accumulated in roots when plants were excessively supplied with ammonium; however, the GS activity was controlled at a constant level. The discrepancy between the protein content and enzyme activity of GS1 was attributable to the kinetic properties and expression of four distinct isoenzymes encoded by GLN1;1, GLN1;2, GLN1;3 and GLN1;4, genes that function complementary to each other in Arabidopsis roots. GLN1;2 was the only isoenzyme significantly up-regulated by ammonium, which correlated with the rapid increase in total GS1 protein. GLN1;2 was localized in the vasculature and exhibited low affinities to ammonium (Km = 2450 +/- 150 microm) and glutamate (Km = 3.8 +/- 0.2 mm). The expression of the counterpart vascular tissue-localizing low affinity isoenzyme, GLN1;3, was not stimulated by ammonium; however, the enzyme activity of GLN1;3 was significantly inhibited by a high concentration of glutamate. By contrast, the high affinity isoenzyme, GLN1;1 (Km for ammonium < 10 microm; Km for glutamate = 1.1 +/- 0.4 mm) was abundantly accumulated in the surface layers of roots during nitrogen limitation and was down-regulated by ammonium excess. GLN1;4 was another high affinity-type GS1 expressed in nitrogen-starved plants but was 10-fold less abundant than GLN1;1. These results suggested that dynamic regulations of high and low affinity GS1 isoenzymes at the levels of mRNA and enzyme activities are dependent on nitrogen availabilities and may contribute to the homeostatic control of glutamine synthesis in Arabidopsis roots.
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Affiliation(s)
- Keiki Ishiyama
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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Suenaga A, Moriya K, Sonoda Y, Ikeda A, Von Wirén N, Hayakawa T, Yamaguchi J, Yamaya T. Constitutive expression of a novel-type ammonium transporter OsAMT2 in rice plants. PLANT & CELL PHYSIOLOGY 2003; 44:206-11. [PMID: 12610225 DOI: 10.1093/pcp/pcg017] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
To characterize ammonium transport pathways in rice, two cDNAs with high homology to MEP/AMT2-type ammonium transporters, OsAMT2;1 and OsAMT3;1, were isolated. Expression of OsAMT2;1 in an ammonium-uptake-defective yeast mutant showed that this gene encodes functional ammonium transporters. OsAMT2;1 was constitutively expressed in both roots and shoots irrespective of the supply of inorganic nitrogen to the medium, whereas OsAMT3;1 expression was relatively weak. A database search with the amino acid sequence of OsAMT2;1 showed that there are 10 putative OsAMT genes in rice, i.e. three each for OsAMT1, OsAMT2 and OsAMT3, respectively, and one for OsAMT4.
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Affiliation(s)
- Arata Suenaga
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555 Japan
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