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Wang Y, Dai X, Xu G, Dai Z, Chen P, Zhang T, Zhang H. The Ca 2+-CaM Signaling Pathway Mediates Potassium Uptake by Regulating Reactive Oxygen Species Homeostasis in Tobacco Roots Under Low-K + Stress. FRONTIERS IN PLANT SCIENCE 2021; 12:658609. [PMID: 34163499 PMCID: PMC8216240 DOI: 10.3389/fpls.2021.658609] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/19/2021] [Indexed: 05/31/2023]
Abstract
Potassium (K+) deficiency severely threatens crop growth and productivity. Calcium (Ca2+) signaling and its sensors play a central role in the response to low-K+ stress. Calmodulin (CaM) is an important Ca2+ sensor. However, the mechanism by which Ca2+ signaling and CaM mediate the response of roots to low-K+ stress remains unclear. In this study, we found that the K+ concentration significantly decreased in both shoots and roots treated with Ca2+ channel blockers, a Ca2+ chelator, and CaM antagonists. Under low-K+ stress, reactive oxygen species (ROS) accumulated, and the activity of antioxidant enzymes, NAD kinase (NADK), and NADP phosphatase (NADPase) decreased. This indicates that antioxidant enzymes, NADK, and NADPase might be downstream target proteins in the Ca2+-CaM signaling pathway, which facilitates K+ uptake in plant roots by mediating ROS homeostasis under low-K+ stress. Moreover, the expression of NtCNGC3, NtCNGC10, K+ channel genes, and transporter genes was significantly downregulated in blocker-treated, chelator-treated, and antagonist-treated plant roots in the low K+ treatment, suggesting that the Ca2+-CaM signaling pathway may mediate K+ uptake by regulating the expression of these genes. Overall, this study shows that the Ca2+-CaM signaling pathway promotes K+ absorption by regulating ROS homeostasis and the expression of K+ uptake-related genes in plant roots under low-K+ stress.
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Wu J, Qu H, Jin C, Shang Z, Wu J, Xu G, Gao Y, Zhang S. cAMP activates hyperpolarization-activated Ca2+ channels in the pollen of Pyrus pyrifolia. PLANT CELL REPORTS 2011; 30:1193-1200. [PMID: 21331543 DOI: 10.1007/s00299-011-1027-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 01/23/2011] [Accepted: 01/25/2011] [Indexed: 05/30/2023]
Abstract
Many signal-transduction processes in plant cells have been suggested to be triggered by signal-induced opening of calcium ion (Ca(2+)) channels in the plasma membrane. Cyclic nucleotides have been proposed to lead to an increase in cytosolic free Ca(2+) in pollen. However, direct recordings of cyclic-nucleotide-induced Ca(2+) currents in pollen have not yet been obtained. Here, we report that cyclic AMP (cAMP) activated a hyperpolarization-activated Ca(2+) channel in the Pyrus pyrifolia pollen tube using the patch-clamp technique, which resulted in a significant increase in pollen tube protoplast cytosolic-Ca(2+) concentration. Outside-out single channel configuration identified that cAMP directly increased the Ca(2+) channel open-probability without affecting channel conductance. cAMP-induced currents were composed of both Ca(2+) and K(+). However, cGMP failed to mimic the cAMP effect. Higher cytosolic free-Ca(2+) concentration significantly decreased the cAMP-induced currents. These results provide direct evidence for cAMP activation of hyperpolarization-activated Ca(2+) channels in the plasma membrane of pollen tubes, which, in turn, modulate cellular responses in regulation of pollen tube growth.
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Affiliation(s)
- Juyou Wu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, No. 6 Tongwei Road, Nanjing, China
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3
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Methyl jasmonate-induced enhancement of expression activity of Am-FaPS-1, a putative farnesyl diphosphate synthase gene from Aquilaria microcarpa. J Nat Med 2010; 65:194-7. [DOI: 10.1007/s11418-010-0451-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 07/05/2010] [Indexed: 11/25/2022]
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4
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Mitamura T, Shite M, Yamamura Y, Kurosaki F. Cloning and characterization of a gene encoding Rac/Rop-like monomeric guanosine 5'-triphosphate-binding protein from Scoparia dulcis. Biol Pharm Bull 2009; 32:1122-5. [PMID: 19483328 DOI: 10.1248/bpb.32.1122] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A cDNA clone, designated Sd-racrop (969 bp), was isolated from seedlings of Scoparia dulcis. This gene contains an open reading frame encoding the protein of 197 amino acid residues with high homology to Rac/Rop small guanosine 5'-triphosphate-binding proteins from various plant sources. In Southern hybridization analysis, the restriction digests prepared from genomic DNA of S. dulcis showed a main signal together with a few weakly hybridized bands. The transcriptional level of Sd-racrop showed a transient decrease by exposure of the leaf tissues of S. dulcis to the ethylene-generating reagent 2-chloroethylphosphonic acid. However, an appreciable increase in gene expression was reproducibly observed upon treatment of the plant with methyl jasmonate. These results suggest that the Sd-racrop product plays roles in ethylene- and methyl jasmonate-induced responses of S. dulcis accompanying the change in the transcriptional level, however, the cellular events mediated by this protein toward these external stimuli would be regulated by various mechanisms.
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Affiliation(s)
- Toshiaki Mitamura
- Laboratory of Plant Resource Sciences, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
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5
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Stockman G, Boland R. Integration of Plasma Membrane and Nuclear Signaling in Elicitor Regulation of Plant Secondary Metabolism. Nat Prod Commun 2008. [DOI: 10.1177/1934578x0800300803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The plant kingdom represents a valuable source of natural products of commercial interest. These compounds, named secondary metabolites, are not essential for the survival of plants, but confer them some advantages that allow adaptation to changes in their environment. Nevertheless, yields of secondary metabolites are low for commercial purposes, so it has become important to design strategies for increasing their production. Plants manage to adapt to physical changes in their environment, defending themselves against pathogen attack or herbivore wounding. Such aggressive stimuli, also known as elicitors, initiate signaling metabolic cascades that induce accumulation of certain secondary metabolites. Progress has been recently achieved in the understanding of signaling events originating from elicitation and related transcriptional regulation. These advances will allow maneuvering expression of key enzymes implicated in biosynthetic pathways of secondary metabolites, thereby enhancing their accumulation.
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Affiliation(s)
- Gastón Stockman
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Buenos Aires 8000, Argentina
| | - Ricardo Boland
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Buenos Aires 8000, Argentina
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6
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Uematsu K, Fukui Y. Role and regulation of cAMP in seed germination of Phacelia tanacetifolia. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:768-774. [PMID: 18657429 DOI: 10.1016/j.plaphy.2007.10.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Indexed: 05/26/2023]
Abstract
Although adenosine 3',5'-cyclic monophosphate (cAMP) is known as a key second messenger in many living organisms, regulating a wide range of cellular responses, its biological function in higher plants is not well understood. In this study, the role and the regulation mechanism of cAMP in seed germination of Phacelia tanacetifolia Benth. were examined. The cAMP level of the seeds incubated under optimal conditions for germination showed a transient elevation before germination. When the seeds were exposed to light or supraoptimal temperature during incubation, elevation of cAMP levels as well as germination of the seeds were inhibited. Addition of membrane-permeable cAMP to the medium restored the germination rates of these seeds, suggesting that cAMP functions during germination. Treatment of the seeds with gibberellin (GA) was also effective to restore the elevation of cAMP levels and germination of the seeds. Uniconazole, a potent inhibitor of GA biosynthesis, blocked elevation of cAMP level under optimal conditions for germination. These results suggest that cAMP plays a role in the regulation of germination and that the cAMP level is regulated by GA in P. tanacetifolia seeds.
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Affiliation(s)
- Kimio Uematsu
- Department of Applied Biological Chemistry, Laboratory of Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, Tokyo, Japan
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7
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Tezuka T, Akita I, Yoshino N. Self-incompatibility involved in the level of acetylcholine and cAMP. PLANT SIGNALING & BEHAVIOR 2007; 2:475-6. [PMID: 19704589 PMCID: PMC2634339 DOI: 10.4161/psb.2.6.4483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Accepted: 05/24/2007] [Indexed: 05/09/2023]
Abstract
Elongation of pollen tubes in pistils after self-pollination of Lilium longiflorum cv. Hinomoto exhibiting strong gametophytic self-incompatibility was promoted by cAMP and also promoted by some metabolic modulators, namely, activators (forskolin and cholera toxin) of adenylate cyclase and inhibitors (3-isobutyl-1-methylxanthine and pertussis) of cyclic nucleotide phosphodiesterase. Moreover, the elongation was promoted by acetylcholine (ACh) and other choline derivatives, such as acetylthiocholine, L-alpha-phosphatidylcholine and chlorocholinechloride [CCC; (2-chloroethyl) trimethyl ammonium chloride]. A potent inhibitor (neostigmine) of acetylcholinesterase (AChE) as well as acetylcholine also promoted the elongation. cAMP enhanced choline acetyltransferase (ChAT) activity and suppressed AChE activity in the pistils, suggesting that the results are closely correlated with self-incompatibility in L. longiflorum. In short, it came to light that cAMP modulates ChAT (acetylcholine-forming enzyme) and AChE (acetylchoine-decomposing enzyme) activities to enhance the level of ACh in the pistils of L. logiflorum after self-incompatible pollination. These results indicate that the self-incompatibility on self-pollination is caused by low levels of ACh and/or cAMP.
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Affiliation(s)
- Takafumi Tezuka
- Division of Life Sciences, Graduate School of Science; Nagoya University; Nagoya, Japan
- School of Health and Human Life; Nagoya Bunri University; Inazawa, Japan
| | - Isamu Akita
- Division of Informatics for Natural Sciences, Graduate School of Human Informatics; Nagoya University; Nagoya, Japan
| | - Natsuko Yoshino
- Division of Technical Cooperation; Graduate School of Information Science; Nagoya University; Nagoya, Japan
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Lazzaro MD, Cardenas L, Bhatt AP, Justus CD, Phillips MS, Holdaway-Clarke TL, Hepler PK. Calcium gradients in conifer pollen tubes; dynamic properties differ from those seen in angiosperms. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:2619-28. [PMID: 16118258 DOI: 10.1093/jxb/eri256] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Pollen tubes are an established model system for examining polarized cell growth. The focus here is on pollen tubes of the conifer Norway spruce (Picea abies, Pinaceae); examining the relationship between cytosolic free Ca2+, tip elongation, and intracellular motility. Conifer pollen tubes show important differences from their angiosperm counterparts; they grow more slowly and their organelles move in an unusual fountain pattern, as opposed to reverse fountain, in the tip. Ratiometric ion imaging of growing pollen tubes, microinjected with fura-2-dextran, reveals a tip-focused [Ca2+]i gradient extending from 450 nM at the extreme apex to 225 nM at the base of the tip clear zone. Injection of 5,5' dibromo-BAPTA does not dissipate the apical gradient, but stops cell elongation and uniquely causes rapid, transient increases of apical free Ca2+. The [Ca2+]i gradient is, however, dissipated by reversible perfusion of extracellular caffeine. When the basal cytosolic free Ca2+ concentration falls below 150 nM, again a large increase in apical [Ca2+]i occurs. An external source of calcium is not required for germination but significantly enhances elongation. However, both germination and elongation are significantly inhibited by the inclusion of calcium channels blockers, including lanthanum, gadolinium, or verapamil. Modulation of intracellular calcium also affects organelle position and motility. Extracellular perfusion of lanthanides reversibly depletes the apical [Ca2+]i gradient, altering organelle positioning in the tip. Later, during recovery from lanthanide perfusion, organelle motility switches direction to a reverse fountain. When taken together these data show a unique interplay in Picea abies pollen tubes between intracellular calcium and the motile processes controlling cellular organization.
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Affiliation(s)
- Mark D Lazzaro
- Department of Biology, College of Charleston, Charleston, SC 29424, USA.
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9
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Zhao J, Davis LC, Verpoorte R. Elicitor signal transduction leading to production of plant secondary metabolites. Biotechnol Adv 2005; 23:283-333. [PMID: 15848039 DOI: 10.1016/j.biotechadv.2005.01.003] [Citation(s) in RCA: 868] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2004] [Revised: 01/27/2005] [Accepted: 01/31/2005] [Indexed: 11/30/2022]
Abstract
Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and other industrial materials. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Understanding signal transduction paths underlying elicitor-induced production of secondary metabolites is important for optimizing their commercial production. This paper summarizes progress made on several aspects of elicitor signal transduction leading to production of plant secondary metabolites, including: elicitor signal perception by various receptors of plants; avirulence determinants and corresponding plant R proteins; heterotrimeric and small GTP binding proteins; ion fluxes, especially Ca2+ influx, and Ca2+ signaling; medium alkalinization and cytoplasmic acidification; oxidative burst and reactive oxygen species; inositol trisphosphates and cyclic nucleotides (cAMP and cGMP); salicylic acid and nitric oxide; jasmonate, ethylene, and abscisic acid signaling; oxylipin signals such as allene oxide synthase-dependent jasmonate and hydroperoxide lyase-dependent C12 and C6 volatiles; as well as other lipid messengers such as lysophosphatidylcholine, phosphatidic acid, and diacylglycerol. All these signal components are employed directly or indirectly by elicitors for induction of plant secondary metabolite accumulation. Cross-talk between different signaling pathways is very common in plant defense response, thus the cross-talk amongst these signaling pathways, such as elicitor and jasmonate, jasmonate and ethylene, and each of these with reactive oxygen species, is discussed separately. This review also highlights the integration of multiple signaling pathways into or by transcription factors, as well as the linkage of the above signal components in elicitor signaling network through protein phosphorylation and dephosphorylation. Some perspectives on elicitor signal transduction and plant secondary metabolism at the transcriptome and metabolome levels are also presented.
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Affiliation(s)
- Jian Zhao
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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10
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Ishigaki E, Asamizu T, Arisawa M, Kurosaki F. Cloning and expression of calmodulin genes regulating phytoalexin production in carrot cells. Biol Pharm Bull 2005; 27:1308-11. [PMID: 15305044 DOI: 10.1248/bpb.27.1308] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A homology-based cloning strategy yielded four cDNA clones encoding the open reading frame of carrot calmodulin, designated cam-4 and cam-8 from an oligogalacturonide elicitor-treated cell culture and cam-11 and cam-16 from cells exposed to ethylene, respectively. Reverse-transcription polymerase chain reaction analyses revealed that the expression of the cam-4 gene increased transiently when carrot seedlings were treated with oligogalacturonides, although, the cells incubated with fungal mycelial walls or ethylene did not show a significant change in the expression level. In contrast, marked and transient expression was observed for either cam-11 or cam-16 only when carrot cells were treated with ethylene. These results suggest that two classes of stimuli which are capable of triggering phytoalexin production in carrot cells, oligogalacturonides and ethylene, evoke the activation of the Ca2+ cascade in the cells by expressing distinct calmodulin genes to initiate the biosynthesis of the compound.
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Affiliation(s)
- Eriko Ishigaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Toyama, Japan
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11
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Ishigaki E, Sugiyama R, Kurosaki F. Multiple Forms of Calmodulin Genes in Carrot Treated with Fungal Mycelial Walls. Biol Pharm Bull 2005; 28:1109-12. [PMID: 15930757 DOI: 10.1248/bpb.28.1109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eleven cDNA clones encoding the open-reading frame of calmodulin and calmodulin-like proteins were isolated from carrot seedlings treated with fungal mycelial walls. These calmodulin genes were mainly expressed in the stems and leaves of carrot, although the transcriptional level was almost negligible in the seeds and root tissues. Based on nucleotide homology, these genes were divided into two classes, class I and class II, and reverse transcription-polymerase chain reaction analyses revealed that the expression level of class II genes transiently increased when carrot seedlings were treated with the mycelial walls. In contrast, the level of class I genes apparently did not show any significant change even after treatment with the fungal components. These results suggest that the defense responses induced in the fungi-infected carrot accompany the increase in the transcriptional levels of a certain calmodulin gene(s).
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Affiliation(s)
- Eriko Ishigaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan
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12
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Abstract
The natural occurrence of cyclic nucleotides in higher plants, formerly a topic of fierce debate, is now established, as is the presence of nucleotidyl cyclases and cyclic nucleotide phosphodiesterases capable of their synthesis and breakdown. Here we describe the significant properties of cyclic nucleotides, also outlining their second messenger functions and the history of plant cyclic nucleotide research over its first three decades. Findings of the last five years are detailed within the context of the functional role of cyclic nucleotides in higher plants, with particular emphasis upon nucleotidyl cyclases and cyclic nucleotide-responsive protein kinases, -binding proteins and -gated ion channels, with future objectives and strategies discussed.
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Affiliation(s)
- Russell P Newton
- Biochemistry Group, School of Biological Sciences, Wallace Building, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, UK.
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Rato C, Monteiro D, Hepler PK, Malhó R. Calmodulin activity and cAMP signalling modulate growth and apical secretion in pollen tubes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 38:887-897. [PMID: 15165182 DOI: 10.1111/j.1365-313x.2004.02091.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Our present understanding implicates both calmodulin (CaM) and 3',5'-cyclicAMP (cAMP) in the regulation of pollen tube growth. However, downstream molecules of these signalling pathways and the cellular processes they modulate remain largely unknown. In order to elucidate the role of CaM, we mapped its activity in growing pollen tubes. 2-chloro-(epsilon-amino-Lys(75))-[6-4-(N,N'-diethylaminophenyl)-1,3,5-triazin-4-yl]-calmodulin (TA-CaM) and fluorescein-calmodulin (FL-CaM), fluorescent analogues of CaM, were loaded into pollen tubes and CaM activity was mapped by fluorescence ratio imaging. It was found that CaM activity exhibits a tip-focused gradient, similar to the distribution of cytosolic-free calcium ([Ca(2+)](c)). In long pollen tubes, apical CaM activity was also found to oscillate with a period similar to [Ca(2+)](c) (40-80 sec). This oscillatory behaviour was not observed in small pollen tubes or in tubes that had stopped growing. Changes in CaM activity within the dome of the pollen tube apex resulting from the photolysis of caged photolysis of RS-20 (a peptide antagonist of CaM) induced re-orientation of the growth axis, suggesting that CaM is also involved in the guidance mechanism. CaM activity was strongly modulated by intracellular changes in cAMP (induced by activators and antagonists of adenylyl cyclase). These results indicate that the action of this protein is dependent not solely on [Ca(2+)](c) but also on a cross-talk with other signalling pathways. A putative target of this cross-talk is the secretory machinery as observed in pollen tubes loaded with the FM (N-(3-triethylammoniumpropyl)-4-(4-dibutylamino)styryl)pyridinium dibromide 1-43 dye and exposed to different antagonists and activators of these molecules. Our data thus suggest that pollen tube growth and orientation depend on an intricate cross-talk between multiple signalling pathways in which CaM is a key element.
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Affiliation(s)
- Cláudia Rato
- Departamento de Biologia Vegetal, Faculdade de Ciências de Lisboa, ICAT, Campo Grande, 1749-016 Lisbon, Portugal
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Zhao J, Guo Y, Fujita K, Sakai K. Involvement of cAMP signaling in elicitor-induced phytoalexin accumulation in Cupressus lusitanica cell cultures. THE NEW PHYTOLOGIST 2004; 161:723-733. [PMID: 33873708 DOI: 10.1111/j.1469-8137.2004.00976.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• An increasing body of evidence on plant electrophysiology, biochemistry, and molecular biology shows that cAMP exists in higher plants and plays a role in several physiological processes by affecting potassium (K+ ) or calcium (Ca2+ ) fluxes. Our study here reports that cAMP is involved in elicitor-induced accumulation of a phytoalexin, β-thujaplicin, in Cupressus lusitanica cell cultures. • Treatment of C. lusitanica cultured cells with cAMP or its analogues stimulated β-thujaplicin accumulation. Cholera toxin and forskolin, activators of adenylyl cyclase, also stimulated β-thujaplicin accumulation. Enzyme immunoassay showed that after elicitor treatment, cAMP level in the elicited cells quickly increased to about three- to five-fold over the control. Cholera toxin and forskolin also stimulated cAMP accumulation in the absence of elicitor. • However, K+ and Ca2+ channel blockers inhibited the β-thujaplicin accumulation induced by cAMP analogues, suggesting that the cAMP-stimulated β-thujaplicin accumulation may involve Ca2+ and K+ fluxes. Several ionophores mimicked cAMP induction of β-thujaplicin accumulation. • Cross-talk between cAMP treatment and the ethylene signaling pathway was also observed to work in the cell cultures via Ca2+ signaling. The study also indicates an involvement of protein kinase cascades in cAMP signaling processes, leading to both phytoalexin and ethylene production.
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Affiliation(s)
- Jian Zhao
- Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050 China
| | - Yingqing Guo
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050 China
| | - Koki Fujita
- Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan
| | - Kokki Sakai
- Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581 Japan
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15
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Richards H, Das S, Smith CJ, Pereira L, Geisbrecht A, Devitt NJ, Games DE, van Geyschem J, Gareth Brenton A, Newton RP. Cyclic nucleotide content of tobacco BY-2 cells. PHYTOCHEMISTRY 2002; 61:531-7. [PMID: 12409019 DOI: 10.1016/s0031-9422(02)00266-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The cyclic nucleotide content of cultured tobacco bright yellow-2 (BY-2) cells was determined, after freeze-killing, perchlorate extraction and sequential chromatography, by radioimmunoassay. The identities of the putative cyclic nucleotides, adenosine 3',5'-cyclic monophosphate (cyclic AMP), guanosine 3',5'-cyclic monophosphate (cyclic GMP) and cytidine 3',5'-cyclic monophosphate (cyclic CMP) were unambiguously confirmed by tandem mass spectrometry. The potential of BY-2 cell cultures as a model system for future investigations of cyclic nucleotide function in higher plants is discussed.
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Affiliation(s)
- Helen Richards
- Biochemistry Group, Wallace Building, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, UK
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16
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Meijer HJG, ter Riet B, van Himbergen JAJ, Musgrave A, Munnik T. KCl activates phospholipase D at two different concentration ranges: distinguishing between hyperosmotic stress and membrane depolarization. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 31:51-9. [PMID: 12100482 DOI: 10.1046/j.1365-313x.2002.01336.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Hyperosmotic stress induces the rapid formation of phosphatidic acid (PA) in Chlamydomonas moewusii via the activation of two signalling pathways: phospholipase D (PLD) and phospholipase C (PLC), the latter in combination with diacylglycerol kinase (DGK) (Munnik et al., 2000). A concomitant increase in cell Ca(2+) becomes manifest as deflagellation. When KCl was used as osmoticum we found that two concentration ranges activated deflagellation: one between 50 and 100 mm and another above 200 mm. Deflagellation in low KCl concentrations was complete within 30 sec whereas in high concentrations it took 5 min. PLC was not activated, as it was by high KCl concentrations that cause hyperosmotic stress. Moreover PLD was activated more strongly by low than by high KCl concentrations. Potassium was the most potent monovalent cation based on the induction of deflagellation and the formation of PA and PBut. During treatment, the external medium acidified, indicating an increase in H(+)-ATPase activity in order to re-establish the membrane potential. Activation of PLD and deflagellation at low KCl concentrations were abrogated by treatment with La(3+), Gd(3+) and EGTA, indicating the dependency on extracellular Ca(2+). This suggests that low concentrations of KCl depolarize the plasma membrane, resulting in the activation of H(+)-ATPases and opening voltage-dependent Ca(2+) +/- channels, observed as deflagellation and an increase in PLD activity.
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Affiliation(s)
- Harold J G Meijer
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, Kruislaan 318, NL-1098 SM Amsterdam, The Netherlands
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Kurosaki F, Yamashita A, Arisawa M. Determination of Ca(2+) influx across plant plasma membrane with sealed vesicles reoriented by Brij 58. Anal Biochem 2001; 299:266-8. [PMID: 11730354 DOI: 10.1006/abio.2001.5426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-0194, Japan
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18
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Tsuruhara A, Tezuka T. Relationship between the self-incompatibility and cAMP level in Lilium longiflorum. PLANT & CELL PHYSIOLOGY 2001; 42:1234-8. [PMID: 11726708 DOI: 10.1093/pcp/pce159] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The elongation of pollen tubes in Lilium longiflorum cv. Hinomoto after self-incompatible pollination stopped halfway, but that after cross-compatible pollination (cross with cv. Georgia) did not. The elongation of pollen tubes after self-pollination was enhanced by exogenous cAMP and by pertussis toxin or cholera toxin, which activates adenylate cyclase. The level of endogenous cAMP in pistils after self-pollination was approximately one half of that after cross-pollination. Furthermore, the activity of adenylate cyclase in pistils after self-pollination was also approximately one half of that after cross-pollination. By contrast, cAMP phosphodiesterase in pistils after self-pollination was approximately 2 times as high as that after cross-pollination. A possible correlation between self-incompatibility and the low level of endogenous cAMP in lily pistils is discussed on the basis of these results.
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Affiliation(s)
- A Tsuruhara
- Division of Informatics for Natural Sciences, Graduate School of Human Informatics, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan
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Kurosaki F, Yamashita A, Arisawa M. Involvement of GTP-binding protein in the induction of phytoalexin biosynthesis in cultured carrot cells. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2001; 161:273-278. [PMID: 11448758 DOI: 10.1016/s0168-9452(01)00407-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Biosynthetic activity of carrot phytoalexin 6-methoxymellen was induced in cell suspension culture by the treatment with oligogalacturonide elicitor; however, the elicitor-induced activity appreciably reduced in the presence of suramin, a potent inhibitor of GTP-binding proteins. In contrast, addition of G-protein activators, such as mastoparan or GTP-gamma-S, to carrot cell culture triggered 6-methoxymellein production even in the absence of uronide elicitor. An appreciable GTPase activity was found in purified plasma membrane of cultured carrot cells, and the hydrolytic activity was significantly increased by the addition of elicitor. Carrot plasma membrane was capable of associating with GTP-gamma-S, and the binding ability was markedly increased in the presence of elicitor. However, the binding activity markedly decreased when the membrane preparation was pre-incubated with GTP but not with ATP. These observations strongly suggest that a certain GTP-binding protein located at plasma membrane of cultured carrot cells plays an important role in the oligogalacturonide elicitor-induced 6-methoxymellein production.
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Affiliation(s)
- F Kurosaki
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, 930-0194, Toyama, Japan
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20
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Snedden WA, Fromm H. Calmodulin as a versatile calcium signal transducer in plants. THE NEW PHYTOLOGIST 2001; 151:35-66. [PMID: 33873389 DOI: 10.1046/j.1469-8137.2001.00154.x] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The complexity of Ca2+ patterns observed in eukaryotic cells, including plants, has led to the hypothesis that specific patterns of Ca2+ propagation, termed Ca2+ signatures, encode information and relay it to downstream elements (effectors) for translation into appropriate cellular responses. Ca2+ -binding proteins (sensors) play a key role in decoding Ca2+ signatures and transducing signals by activating specific targets and pathways. Calmodulin is a Ca2+ sensor known to modulate the activity of many mammalian proteins, whose targets in plants are now being actively characterized. Plants possess an interesting and rapidly growing list of calmodulin targets with a variety of cellular roles. Nevertheless, many targets appear to be unique to plants and remain uncharacterized, calling for a concerted effort to elucidate their functions. Moreover, the extended family of calmodulin-related proteins in plants consists of evolutionarily divergent members, mostly of unknown function, although some have recently been implicated in stress responses. It is hoped that advances in functional genomics, and the research tools it generates, will help to explain themultiplicity of calmodulin genes in plants, and to identify their downstream effectors. This review summarizes current knowledge of the Ca2+ -calmodulin messenger system in plants and presents suggestions for future areas of research. Contents I. Introduction 36 II. CaM isoforms and CaM-like proteins 37 III. CaM-target proteins 42 IV. CaM and nuclear functions 46 V. Regulation of ion transport 49 VI. CaM and plant responses to environmental stimuli 52 VII. Conclusions and future studies 58 Acknowledgements 59 References 59.
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Affiliation(s)
- Wayne A Snedden
- Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
| | - Hillel Fromm
- Centre for Plant Sciences, Leeds Institute for Biotechnology and Agriculture (LIBA), School of Biology, University of Leeds, Leeds LS2 9JT, UK
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Leng Q, Mercier RW, Yao W, Berkowitz GA. Cloning and first functional characterization of a plant cyclic nucleotide-gated cation channel. PLANT PHYSIOLOGY 1999; 121:753-61. [PMID: 10557223 PMCID: PMC59437 DOI: 10.1104/pp.121.3.753] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/1999] [Accepted: 07/30/1999] [Indexed: 05/18/2023]
Abstract
Cyclic nucleotide-gated (cng) non-selective cation channels have been cloned from a number of animal systems. These channels are characterized by direct gating upon cAMP or cGMP binding to the intracellular portion of the channel protein, which leads to an increase in channel conductance. Animal cng channels are involved in signal transduction systems; they translate stimulus-induced changes in cytosolic cyclic nucleotide into altered cell membrane potential and/or cation flux as part of a signal cascade pathway. Putative plant homologs of animal cng channels have been identified. However, functional characterization (i.e. demonstration of cyclic-nucleotide-dependent ion currents) of a plant cng channel has not yet been accomplished. We report the cloning and first functional characterization of a plant member of this family of ion channels. The Arabidopsis cDNA AtCNGC2 encodes a polypeptide with deduced homology to the alpha-subunit of animal channels, and facilitates cyclic nucleotide-dependent cation currents upon expression in a number of heterologous systems. AtCNGC2 expression in a yeast mutant lacking a low-affinity K(+) uptake system complements growth inhibition only when lipophilic cyclic nucleotides are present in the culture medium. Voltage clamp analysis indicates that Xenopus laevis oocytes injected with AtCNGC2 cRNA demonstrate cyclic-nucleotide-dependent, inward-rectifying K(+) currents. Human embryonic kidney cells (HEK293) transfected with AtCNGC2 cDNA demonstrate increased permeability to Ca(2+) only in the presence of lipophilic cyclic nucleotides. The evidence presented here supports the functional classification of AtCNGC2 as a cyclic-nucleotide-gated cation channel, and presents the first direct evidence (to our knowledge) identifying a plant member of this ion channel family.
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Affiliation(s)
- Q Leng
- Department of Plant Science U-67, 1376 Storrs Road, University of Connecticut, Storrs, Connecticut 06269-4067, USA
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