1
|
Ma Y, Garrido K, Ali R, Berkowitz GA. Phenotypes of cyclic nucleotide-gated cation channel mutants: probing the nature of native channels. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:1223-1236. [PMID: 36633062 DOI: 10.1111/tpj.16106] [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: 10/20/2022] [Revised: 12/30/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Plant cyclic nucleotide gated channels (CNGCs) facilitate cytosolic Ca2+ influx as an early step in numerous signaling cascades. CNGC-mediated Ca2+ elevations are essential for plant immune defense and high temperature thermosensing. In the present study, we evaluated phenotypes of CNGC2, CNGC4, CNGC6, and CNGC12 null mutants in these two pathways. It is shown CNGC2, CNGC4, and CNGC6 physically interact in vivo, whereas CNGC12 does not. CNGC involvement in immune signaling was evaluated by monitoring mutant response to elicitor peptide Pep3. Pep3 response cascades involving CNGCs included mitogen-activated kinase activation mediated by Ca2+ -dependent protein kinase phosphorylation. Pep3-induced reactive oxygen species generation was impaired in cngc2, cngc4, and cngc6, but not in cngc12, suggesting that CNGC2, CNGC4, and CNGC6 (which physically interact) may be components of a multimeric CNGC channel complex for immune signaling. However, unlike cngc2 and cngc4, cngc6 is not sensitive to high Ca2+ and displays no pleiotropic dwarfism. All four cngc mutants showed thermotolerance compared to wild-type, although CNGC12 does not interact with the other three CNGCs. These results imply that physically interacting CNGCs may, in some cases, function in a signaling cascade as components of a heteromeric channel complex, although this may not be the case in other signaling pathways.
Collapse
Affiliation(s)
- Yi Ma
- Department of Plant Science and Landscape Architecture, Agricultural Biotechnology Laboratory, University of Connecticut, Storrs, CT, 06269, USA
| | | | | | - Gerald A Berkowitz
- Department of Plant Science and Landscape Architecture, Agricultural Biotechnology Laboratory, University of Connecticut, Storrs, CT, 06269, USA
| |
Collapse
|
2
|
Sabetta W, Vandelle E, Locato V, Costa A, Cimini S, Bittencourt Moura A, Luoni L, Graf A, Viggiano L, De Gara L, Bellin D, Blanco E, de Pinto MC. Genetic buffering of cyclic AMP in Arabidopsis thaliana compromises the plant immune response triggered by an avirulent strain of Pseudomonas syringae pv. tomato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:590-606. [PMID: 30735606 DOI: 10.1111/tpj.14275] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/23/2018] [Accepted: 01/24/2019] [Indexed: 05/21/2023]
Abstract
Cyclic AMP plays important roles in different physiological processes, including plant defence responses. However, as little information is known on plant enzymes responsible for cAMP production/degradation, studies of cAMP functions have relied, to date, on non-specific pharmacological approaches. We therefore developed a more reliable approach, producing transgenic Arabidopsis thaliana lines overexpressing the 'cAMP-sponge' (cAS), a genetic tool that specifically buffers cAMP levels. In response to an avirulent strain of Pseudomonas syringae pv. tomato (PstAvrB), cAS plants showed a higher bacterial growth and a reduced hypersensitive cell death in comparison with wild-type (WT) plants. The low cAMP availability after pathogen infection delayed cytosolic calcium elevation, as well as hydrogen peroxide increase and induction of redox systems. The proteomic analysis, performed 24 h post-infection, indicated that a core of 49 proteins was modulated in both genotypes, while 16 and 42 proteins were uniquely modulated in WT and cAS lines, respectively. The involvement of these proteins in the impairment of defence response in cAS plants is discussed in this paper. Moreover, in silico analysis revealed that the promoter regions of the genes coding for proteins uniquely accumulating in WT plants shared the CGCG motif, a target of the calcium-calmodulin-binding transcription factor AtSR1 (Arabidopsis thaliana signal responsive1). Therefore, following pathogen perception, the low free cAMP content, altering timing and levels of defence signals, and likely acting in part through the mis-regulation of AtSR1 activity, affected the speed and strength of the immune response.
Collapse
Affiliation(s)
- Wilma Sabetta
- Institute of Biosciences and Bioresources, CNR, Research Division Bari, Via Amendola 165/A, 70126, Bari, Italy
| | - Elodie Vandelle
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Vittoria Locato
- Unit of Food Science and Human Nutrition, University Camps Bio-Medico of Rome, via Alvaro del Portillo, 21, 00128, Rome, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, Via G. Celoria 26, 20133, Milano, Italy
| | - Sara Cimini
- Unit of Food Science and Human Nutrition, University Camps Bio-Medico of Rome, via Alvaro del Portillo, 21, 00128, Rome, Italy
| | | | - Laura Luoni
- Department of Biosciences, University of Milan, Via G. Celoria 26, 20133, Milano, Italy
| | - Alexander Graf
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Luigi Viggiano
- Department of Biology, University of Bari "Aldo Moro", Via Orabona 4, 70125, Bari, Italy
| | - Laura De Gara
- Unit of Food Science and Human Nutrition, University Camps Bio-Medico of Rome, via Alvaro del Portillo, 21, 00128, Rome, Italy
| | - Diana Bellin
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Emanuela Blanco
- Institute of Biosciences and Bioresources, CNR, Research Division Bari, Via Amendola 165/A, 70126, Bari, Italy
| | - Maria C de Pinto
- Department of Biology, University of Bari "Aldo Moro", Via Orabona 4, 70125, Bari, Italy
| |
Collapse
|
3
|
Walker RK, Berkowitz GA. Detection of reactive oxygen species downstream of cyclic nucleotide signals in plants. Methods Mol Biol 2013; 1016:245-52. [PMID: 23681584 DOI: 10.1007/978-1-62703-441-8_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cyclic nucleotides act in plant cell signal transduction cascades by activating cyclic nucleotide gated cation-conducting ion channels (CNGCs). Activation of CNGCs results in inward cation (including Ca(2+)) conductance across the plasma membrane. Elevation of cytosolic Ca(2+) is an early step in numerous plant cell signal transduction cascades, including plant immune responses to pathogens. CNGC involvement, along with cyclic nucleotides cAMP and cGMP, in pathogen defense programs is one relatively well-studied area of cyclic nucleotide signaling in plants. During plant immune responses, CNGC-dependent Ca(2+) elevations lead to a signaling cascade that results in the generation of defense molecules such as hydrogen peroxide and nitric oxide, and induction of defense gene expression. This pathogen defense response is discussed, and methods to detect some of the downstream signaling steps in the pathway are presented.
Collapse
Affiliation(s)
- Robin K Walker
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC, USA
| | | |
Collapse
|
4
|
Lemtiri-Chlieh F, Ali R. Characterization of heterologously expressed transporter genes by patch- and voltage-clamp methods: application to cyclic nucleotide-dependent responses. Methods Mol Biol 2013; 1016:67-93. [PMID: 23681573 DOI: 10.1007/978-1-62703-441-8_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The application of patch- and voltage-clamp methods to study ion transport can be limited by many -hurdles: the size of the cells to be patched and/or stabbed, the subcellular localization of the molecule of interest, and its density of expression that could be too low even in their own native environment. Functional expression of genes using recombinant DNA technology not only overcomes those hurdles but also affords additional and elegant investigations such as single-point mutation studies and subunit -associations/regulations. In this chapter, we give a step-by-step description of two electrophysiological methods, patch clamp and two-electrode voltage clamp (TEVC), that are routinely used in combination with heterologous gene expression to assist researchers interested in the identification and characterization of ion transporters. We describe how to (1) obtain and maintain the cells suitable for the use with each of the above-mentioned methods (i.e., HEK-293 cells and yeast spheroplasts to use with the patch-clamp methodology and Xenopus laevis oocytes with TEVC), (2) transfect/inject them with the gene of interest, and (3) record ion transport activities.
Collapse
Affiliation(s)
- Fouad Lemtiri-Chlieh
- Division of Chemical and Life Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | |
Collapse
|
5
|
Abstract
Cyclic nucleotide-gated channels (CNGCs) are nonselective cation channels found in plants, animals, and some bacteria. They have a six-transmembrane/one-pore structure, a cytosolic cyclic nucleotide-binding domain, and a cytosolic calmodulin-binding domain. Despite their functional similarities, the plant CNGC family members appear to have different conserved amino acid motifs within corresponding functional domains than animal and bacterial CNGCs do. Here we describe the development and application of methods employing plant CNGC-specific sequence motifs as diagnostic tools to identify novel candidate channels in different plants. These methods are used to evaluate the validity of annotations of putative orthologs of CNGCs from plant genomes. The methods detail how to employ regular expressions of conserved amino acids in functional domains of annotated CNGCs and together with Web tools such as PHI-BLAST and ScanProsite to identify novel candidate CNGCs in species including Physcomitrella patens.
Collapse
|