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Giovannetti M, Binci F, Navazio L, Genre A. Fungal signals and calcium-mediated transduction pathways along the plant defence-symbiosis continuum. New Phytol 2024; 242:1404-1407. [PMID: 38659109 DOI: 10.1111/nph.19759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
This article is a Commentary on Giovannetti et al., 241: 1393–1400.
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Affiliation(s)
- Marco Giovannetti
- Department of Life Sciences and Systems Biology, University of Torino, 10125, Torino, Italy
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Filippo Binci
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Torino, 10125, Torino, Italy
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2
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Giovannetti M, Binci F, Navazio L, Genre A. Nonbinary fungal signals and calcium-mediated transduction in plant immunity and symbiosis. New Phytol 2024; 241:1393-1400. [PMID: 38013492 DOI: 10.1111/nph.19433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/08/2023] [Indexed: 11/29/2023]
Abstract
Chitin oligomers (COs) are among the most common and active fungal elicitors of plant responses. Short-chain COs from symbiotic arbuscular mycorrhizal fungi activate accommodation responses in the host root, while long-chain COs from pathogenic fungi are acknowledged to trigger defence responses. The modulation of intracellular calcium concentration - a common second messenger in a wide variety of plant signal transduction processes - plays a central role in both signalling pathways with distinct signature features. Nevertheless, mounting evidence suggests that plant immunity and symbiosis signalling partially overlap at multiple levels. Here, we elaborate on recent findings on this topic, highlighting the nonbinary nature of chitin-based fungal signals, their perception and their interpretation through Ca2+ -mediated intracellular signals. Based on this, we propose that plant perception of symbiotic and pathogenic fungi is less clear-cut than previously described and involves a more complex scenario in which partially overlapping and blurred signalling mechanisms act upstream of the unambiguous regulation of gene expression driving accommodation or defence responses.
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Affiliation(s)
- Marco Giovannetti
- Department of Life Sciences and Systems Biology, University of Torino, 10125, Torino, Italy
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Filippo Binci
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, 35131, Padova, Italy
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Torino, 10125, Torino, Italy
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Binci F, Offer E, Crosino A, Sciascia I, Kleine-Vehn J, Genre A, Giovannetti M, Navazio L. Spatially and temporally distinct Ca2+ changes in Lotus japonicus roots orient fungal-triggered signalling pathways towards symbiosis or immunity. J Exp Bot 2024; 75:605-619. [PMID: 37712520 DOI: 10.1093/jxb/erad360] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/13/2023] [Indexed: 09/16/2023]
Abstract
Plants activate an immune or symbiotic response depending on the detection of distinct signals from root-interacting microbes. Both signalling cascades involve Ca2+ as a central mediator of early signal transduction. In this study, we combined aequorin- and cameleon-based methods to dissect the changes in cytosolic and nuclear Ca2+ concentration caused by different chitin-derived fungal elicitors in Lotus japonicus roots. Our quantitative analyses highlighted the dual character of the evoked Ca2+ responses taking advantage of the comparison between different genetic backgrounds: an initial Ca2+ influx, dependent on the LysM receptor CERK6 and independent of the common symbiotic signalling pathway (CSSP), is followed by a second CSSP-dependent and CERK6-independent phase, that corresponds to the well-known perinuclear/nuclear Ca2+ spiking. We show that the expression of immunity marker genes correlates with the amplitude of the first Ca2+ change, depends on elicitor concentration, and is controlled by Ca2+ storage in the vacuole. Our findings provide an insight into the Ca2+-mediated signalling mechanisms discriminating plant immunity- and symbiosis-related pathways in the context of their simultaneous activation by single fungal elicitors.
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Affiliation(s)
- Filippo Binci
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Elisabetta Offer
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Andrea Crosino
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Ivan Sciascia
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Jürgen Kleine-Vehn
- Centre for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany
- Institute of Biology II, Department of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Marco Giovannetti
- Department of Biology, University of Padova, 35131 Padova, Italy
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, 35131 Padova, Italy
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Corti F, Festa M, Stein F, Stevanato P, Siroka J, Navazio L, Vothknecht UC, Alboresi A, Novák O, Formentin E, Szabò I. Comparative analysis of wild-type and chloroplast MCU-deficient plants reveals multiple consequences of chloroplast calcium handling under drought stress. Front Plant Sci 2023; 14:1228060. [PMID: 37692417 PMCID: PMC10485843 DOI: 10.3389/fpls.2023.1228060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/28/2023] [Indexed: 09/12/2023]
Abstract
Introduction Chloroplast calcium homeostasis plays an important role in modulating the response of plants to abiotic and biotic stresses. One of the greatest challenges is to understand how chloroplast calcium-permeable pathways and sensors are regulated in a concerted manner to translate specific information into a calcium signature and to elucidate the downstream effects of specific chloroplast calcium dynamics. One of the six homologs of the mitochondrial calcium uniporter (MCU) was found to be located in chloroplasts in the leaves and to crucially contribute to drought- and oxidative stress-triggered uptake of calcium into this organelle. Methods In the present study we integrated comparative proteomic analysis with biochemical, genetic, cellular, ionomic and hormone analysis in order to gain an insight into how chloroplast calcium channels are integrated into signaling circuits under watered condition and under drought stress. Results Altogether, our results indicate for the first time a link between chloroplast calcium channels and hormone levels, showing an enhanced ABA level in the cmcu mutant already in well-watered condition. Furthermore, we show that the lack of cMCU results in an upregulation of the calcium sensor CAS and of enzymes of chlorophyll synthesis, which are also involved in retrograde signaling upon drought stress, in two independent KO lines generated in Col-0 and Col-4 ecotypes. Conclusions These observations point to chloroplasts as important signaling hubs linked to their calcium dynamics. Our results obtained in the model plant Arabidopsis thaliana are discussed also in light of our limited knowledge regarding organellar calcium signaling in crops and raise the possibility of an involvement of such signaling in response to drought stress also in crops.
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Affiliation(s)
| | | | - Frank Stein
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Piergiorgio Stevanato
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
| | - Jitka Siroka
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Palacký University, Olomouc, Czechia
| | | | - Ute C. Vothknecht
- Plant Cell Biology, Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
| | | | - Ondřej Novák
- Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences & Palacký University, Olomouc, Czechia
| | | | - Ildikò Szabò
- Department of Biology, University of Padua, Padua, Italy
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Cortese E, Moscatiello R, Pettiti F, Carraretto L, Baldan B, Frigerio L, Vothknecht UC, Szabo I, De Stefani D, Brini M, Navazio L. Monitoring calcium handling by the plant endoplasmic reticulum with a low-Ca 2+ -affinity targeted aequorin reporter. Plant J 2022; 109:1014-1027. [PMID: 34837294 PMCID: PMC9299891 DOI: 10.1111/tpj.15610] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 10/05/2021] [Accepted: 11/22/2021] [Indexed: 05/15/2023]
Abstract
Precise measurements of dynamic changes in free Ca2+ concentration in the lumen of the plant endoplasmic reticulum (ER) have been lacking so far, despite increasing evidence for the contribution of this intracellular compartment to Ca2+ homeostasis and signalling in the plant cell. In the present study, we targeted an aequorin chimera with reduced Ca2+ affinity to the ER membrane and facing the ER lumen. To this aim, the cDNA for a low-Ca2+ -affinity aequorin variant (AEQmut) was fused to the nucleotide sequence encoding a non-cleavable N-terminal ER signal peptide (fl2). The correct targeting of fl2-AEQmut was confirmed by immunocytochemical analyses in transgenic Arabidopsis thaliana (Arabidopsis) seedlings. An experimental protocol well-established in animal cells - consisting of ER Ca2+ depletion during photoprotein reconstitution followed by ER Ca2+ refilling - was applied to carry out ER Ca2+ measurements in planta. Rapid and transient increases of the ER luminal Ca2+ concentration ([Ca2+ ]ER ) were recorded in response to different environmental stresses, displaying stimulus-specific Ca2+ signatures. The comparative analysis of ER and chloroplast Ca2+ dynamics indicates a complex interplay of these organelles in shaping cytosolic Ca2+ signals during signal transduction events. Our data highlight significant differences in basal [Ca2+ ]ER and Ca2+ handling by plant ER compared to the animal counterpart. The set-up of an ER-targeted aequorin chimera extends and complements the currently available toolkit of organelle-targeted Ca2+ indicators by adding a reporter that improves our quantitative understanding of Ca2+ homeostasis in the plant endomembrane system.
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Affiliation(s)
- Enrico Cortese
- Department of BiologyUniversity of PadovaPadova35131Italy
| | | | | | | | - Barbara Baldan
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
| | | | - Ute C. Vothknecht
- Plant Cell BiologyInstitute of Cellular and Molecular BotanyUniversity of BonnBonnD‐53115Germany
| | - Ildiko Szabo
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
| | - Diego De Stefani
- Department of Biomedical SciencesUniversity of PadovaPadova35131Italy
| | - Marisa Brini
- Department of BiologyUniversity of PadovaPadova35131Italy
| | - Lorella Navazio
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
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Yao P, Vanneste S, Navazio L, Van Breusegem F, Stael S. Chemical Perturbation of Chloroplast Ca 2+ Dynamics in Arabidopsis thaliana Suspension Cell Cultures and Seedlings. Methods Mol Biol 2022; 2494:149-158. [PMID: 35467206 DOI: 10.1007/978-1-0716-2297-1_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ca2+ signaling is part of universal signal transduction pathways to respond to external and internal stimuli or stress and in plants plays a central role in chloroplasts, such as in the regulation of photosynthetic enzymes or the transition from light to dark. Only recently, the underlying molecular machinery, e.g., transporters and channels that enable chloroplast Ca2+ fluxes, has started to be elucidated. However, chemical tools to specifically perturb these chloroplast Ca2+ fluxes are largely lacking. Here, we describe an efficient aequorin-based system in Arabidopsis thaliana suspension cell cultures to screen for chemicals that alter light-to-dark-induced chloroplast stroma Ca2+ signals. Subsequently, the effect of the hits on chloroplast Ca2+ signals is validated in Arabidopsis seedlings. The research lays a foundation for the identification of novel proteins involved in Ca2+ transport in chloroplast stroma under light-to-dark transition and for investigating the interaction of chloroplast Ca2+ signaling with photosynthesis in general.
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Affiliation(s)
- Panfeng Yao
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB-UGent Center for Plant Systems Biology, Ghent, Belgium
| | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Department of Plants and Crops, Ghent University, Ghent, Belgium
- Lab of Plant Growth Analysis, Ghent University Global Campus, Incheon, Republic of Korea
| | - Lorella Navazio
- Department of Biology, University of Padova, Padova, Italy
- Botanical Garden, University of Padova, Padova, Italy
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB-UGent Center for Plant Systems Biology, Ghent, Belgium
| | - Simon Stael
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.
- VIB-UGent Center for Plant Systems Biology, Ghent, Belgium.
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Cortese E, Settimi AG, Pettenuzzo S, Cappellin L, Galenda A, Famengo A, Dabalà M, Antoni V, Navazio L. Plasma-Activated Water Triggers Rapid and Sustained Cytosolic Ca 2+ Elevations in Arabidopsis thaliana. Plants (Basel) 2021; 10:plants10112516. [PMID: 34834879 PMCID: PMC8622995 DOI: 10.3390/plants10112516] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 05/15/2023]
Abstract
Increasing evidence indicates that water activated by plasma discharge, termed as plasma-activated water (PAW), can promote plant growth and enhance plant defence responses. Nevertheless, the signalling pathways activated in plants in response to PAW are still largely unknown. In this work, we analysed the potential involvement of calcium as an intracellular messenger in the transduction of PAW by plants. To this aim, Arabidopsis thaliana (Arabidopsis) seedlings stably expressing the bioluminescent Ca2+ reporter aequorin in the cytosol were challenged with PAW generated by a plasma torch. Ca2+ measurement assays demonstrated the induction by PAW of rapid and sustained cytosolic Ca2+ elevations in Arabidopsis seedlings. The dynamics of the recorded Ca2+ signals were found to depend upon different parameters, such as the operational conditions of the torch, PAW storage, and dilution. The separate administration of nitrate, nitrite, and hydrogen peroxide at the same doses as those measured in the PAW did not trigger any detectable Ca2+ changes, suggesting that the unique mixture of different reactive chemical species contained in the PAW is responsible for the specific Ca2+ signatures. Unveiling the signalling mechanisms underlying plant perception of PAW may allow to finely tune its generation for applications in agriculture, with potential advantages in the perspective of a more sustainable agriculture.
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Affiliation(s)
- Enrico Cortese
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy;
| | - Alessio G. Settimi
- Department of Industrial Engineering, University of Padova, Via F. Marzolo 9, 35131 Padova, Italy; (A.G.S.); (M.D.)
| | - Silvia Pettenuzzo
- Center Agriculture Food Environment (C3A), University of Trento, Via E. Mach 1, 38010 San Michele all’Adige, Italy;
- Research and Innovation Centre, Edmund Mach Foundation, Via E. Mach 1, 38010 San Michele all’Adige, Italy
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy;
| | - Luca Cappellin
- Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy;
| | - Alessandro Galenda
- CNR Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Corso Stati Uniti 4, 35127 Padova, Italy; (A.G.); (A.F.)
| | - Alessia Famengo
- CNR Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Corso Stati Uniti 4, 35127 Padova, Italy; (A.G.); (A.F.)
| | - Manuele Dabalà
- Department of Industrial Engineering, University of Padova, Via F. Marzolo 9, 35131 Padova, Italy; (A.G.S.); (M.D.)
| | - Vanni Antoni
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy;
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy;
- Botanical Garden, University of Padova, Via Orto Botanico 15, 35123 Padova, Italy
- Correspondence:
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Cortese E, Carraretto L, Baldan B, Navazio L. Arabidopsis Photosynthetic and Heterotrophic Cell Suspension Cultures. Methods Mol Biol 2020; 2200:167-185. [PMID: 33175378 DOI: 10.1007/978-1-0716-0880-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Cell suspension cultures represent a widely used experimental tool suitable to perform a variety of structural and physiological studies in a more simplified system compared to the organism in toto. In this chapter we describe the methods routinely used in our laboratory to establish and maintain Arabidopsis photosynthetic and heterotrophic cell suspension cultures, containing either chloroplasts or amyloplasts, respectively. The use of these in vitro systems may allow to obtain insights into the unique features of chloroplasts versus non-green plastids, as well as their integration in the structural and metabolic compartmentalization of the plant cell.
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Affiliation(s)
- Enrico Cortese
- Department of Biology, University of Padova, Padova, Italy
| | | | - Barbara Baldan
- Department of Biology, University of Padova, Padova, Italy.,Botanical Garden, University of Padova, Padova, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, Padova, Italy. .,Botanical Garden, University of Padova, Padova, Italy.
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Chahed A, Nesler A, Navazio L, Baldan B, Busato I, Ait Barka E, Pertot I, Puopolo G, Perazzolli M. The Rare Sugar Tagatose Differentially Inhibits the Growth of Phytophthora infestans and Phytophthora cinnamomi by Interfering With Mitochondrial Processes. Front Microbiol 2020; 11:128. [PMID: 32117150 PMCID: PMC7015900 DOI: 10.3389/fmicb.2020.00128] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/20/2020] [Indexed: 12/18/2022] Open
Abstract
Rare sugars are monosaccharides with limited availability in nature and their biological functions are largely unknown. Among them, tagatose was developed as a low-calorie sweetener and showed beneficial effects on human health. Tagatose is metabolized by only certain microbial taxa and inhibits the growth of important crop pathogens (e.g., Phytophthora infestans), but its mode of action and the microbial responses are unknown. The aim of this study was to understand the tagatose mode of action against Phytophthora spp., with the final aim of developing new plant protection products. Tagatose inhibited P. infestans growth in vitro and caused severe ultrastructural alterations, with the formation of circular and concentric mitochondrial cristae. Decreased ATP content and reduced oxygen consumption rate (OCR) were found in tagatose-incubated P. infestans as compared to the control, with the consequent accumulation of reactive oxygen species (ROS) and induction of genes related to apoptosis and oxidative stress response. On the other hand, tagatose did not, or only slightly, affect the growth, cellular ultrastructure and mitochondrial processes in Phytophthora cinnamomi, indicating a species-specific response to this rare sugar. The mode of action of tagatose against P. infestans was mainly based on the inhibition of mitochondrial processes and this rare sugar seems to be a promising active substance for the further development of eco-friendly fungicides, thanks to its anti-nutritional properties on some phytopathogens and low risk for human health.
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Affiliation(s)
- Abdessalem Chahed
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Biological Products for Agriculture (Bi-PA), Londerzeel, Belgium.,Department of Plant Induced Resistance and Bioprotection, University of Reims Champagne-Ardenne, Reims, France
| | - Andrea Nesler
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Biological Products for Agriculture (Bi-PA), Londerzeel, Belgium
| | - Lorella Navazio
- Department of Biology, University of Padua, Padua, Italy.,Botanical Garden, University of Padua, Padua, Italy
| | - Barbara Baldan
- Department of Biology, University of Padua, Padua, Italy.,Botanical Garden, University of Padua, Padua, Italy
| | - Isabella Busato
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Department of Biology, University of Padua, Padua, Italy
| | - Essaid Ait Barka
- Department of Plant Induced Resistance and Bioprotection, University of Reims Champagne-Ardenne, Reims, France
| | - Ilaria Pertot
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Center Agriculture Food Environment (C3A), University of Trento, San Michele all'Adige, Italy
| | - Gerardo Puopolo
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Center Agriculture Food Environment (C3A), University of Trento, San Michele all'Adige, Italy
| | - Michele Perazzolli
- Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.,Center Agriculture Food Environment (C3A), University of Trento, San Michele all'Adige, Italy
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10
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Navazio L, Formentin E, Cendron L, Szabò I. Chloroplast Calcium Signaling in the Spotlight. Front Plant Sci 2020; 11:186. [PMID: 32226434 PMCID: PMC7081724 DOI: 10.3389/fpls.2020.00186] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/07/2020] [Indexed: 05/22/2023]
Abstract
Calcium has long been known to regulate the metabolism of chloroplasts, concerning both light and carbon reactions of photosynthesis, as well as additional non photosynthesis-related processes. In addition to undergo Ca2+ regulation, chloroplasts can also influence the overall Ca2+ signaling pathways of the plant cell. Compelling evidence indicate that chloroplasts can generate specific stromal Ca2+ signals and contribute to the fine tuning of cytoplasmic Ca2+ signaling in response to different environmental stimuli. The recent set up of a toolkit of genetically encoded Ca2+ indicators, targeted to different chloroplast subcompartments (envelope, stroma, thylakoids) has helped to unravel the participation of chloroplasts in intracellular Ca2+ handling in resting conditions and during signal transduction. Intra-chloroplast Ca2+ signals have been demonstrated to occur in response to specific environmental stimuli, suggesting a role for these plant-unique organelles in transducing Ca2+-mediated stress signals. In this mini-review we present current knowledge of stimulus-specific intra-chloroplast Ca2+ transients, as well as recent advances in the identification and characterization of Ca2+-permeable channels/transporters localized at chloroplast membranes. In particular, the potential role played by cMCU, a chloroplast-localized member of the mitochondrial calcium uniporter (MCU) family, as component of plant environmental sensing is discussed in detail, taking into account some specific structural features of cMCU. In summary, the recent molecular identification of some players of chloroplast Ca2+ signaling has opened new avenues in this rapidly developing field and will hopefully allow a deeper understanding of the role of chloroplasts in shaping physiological responses in plants.
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Affiliation(s)
- Lorella Navazio
- Department of Biology, University of Padova, Padova, Italy
- Botanical Garden, University of Padova, Padova, Italy
| | - Elide Formentin
- Department of Biology, University of Padova, Padova, Italy
- Botanical Garden, University of Padova, Padova, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, Padova, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padova, Padova, Italy
- Botanical Garden, University of Padova, Padova, Italy
- *Correspondence: Ildikò Szabò,
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11
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Teardo E, Carraretto L, Moscatiello R, Cortese E, Vicario M, Festa M, Maso L, De Bortoli S, Calì T, Vothknecht UC, Formentin E, Cendron L, Navazio L, Szabo I. A chloroplast-localized mitochondrial calcium uniporter transduces osmotic stress in Arabidopsis. Nat Plants 2019; 5:581-588. [PMID: 31182842 DOI: 10.1038/s41477-019-0434-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 04/23/2019] [Indexed: 05/18/2023]
Abstract
Chloroplasts are integral to sensing biotic and abiotic stress in plants, but their role in transducing Ca2+-mediated stress signals remains poorly understood1,2. Here we identify cMCU, a member of the mitochondrial calcium uniporter (MCU) family, as an ion channel mediating Ca2+ flux into chloroplasts in vivo. Using a toolkit of aequorin reporters targeted to chloroplast stroma and the cytosol in cMCU wild-type and knockout lines, we provide evidence that stress-stimulus-specific Ca2+ dynamics in the chloroplast stroma correlate with expression of the channel. Fast downstream signalling events triggered by osmotic stress, involving activation of the mitogen-activated protein kinases (MAPK) MAPK3 and MAPK6, and the transcription factors MYB60 and ethylene-response factor 6 (ERF6), are influenced by cMCU activity. Relative to wild-type plants, cMCU knockouts display increased resistance to long-term water deficit and improved recovery on rewatering. Modulation of stromal Ca2+ in specific processing of stress signals identifies cMCU as a component of plant environmental sensing.
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Affiliation(s)
- Enrico Teardo
- Department of Biology, University of Padova, Padova, Italy
| | | | | | - Enrico Cortese
- Department of Biology, University of Padova, Padova, Italy
| | - Mattia Vicario
- Department of Biology, University of Padova, Padova, Italy
| | | | - Lorenzo Maso
- Department of Biology, University of Padova, Padova, Italy
| | | | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Elide Formentin
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
| | - Laura Cendron
- Department of Biology, University of Padova, Padova, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
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12
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Moscatiello R, Sello S, Ruocco M, Barbulova A, Cortese E, Nigris S, Baldan B, Chiurazzi M, Mariani P, Lorito M, Navazio L. The Hydrophobin HYTLO1 Secreted by the Biocontrol Fungus Trichoderma longibrachiatum Triggers a NAADP-Mediated Calcium Signalling Pathway in Lotus japonicus. Int J Mol Sci 2018; 19:E2596. [PMID: 30200468 PMCID: PMC6164116 DOI: 10.3390/ijms19092596] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 08/29/2018] [Indexed: 12/14/2022] Open
Abstract
Trichoderma filamentous fungi are increasingly used as biocontrol agents and plant biostimulants. Growing evidence indicates that part of the beneficial effects is mediated by the activity of fungal metabolites on the plant host. We have investigated the mechanism of plant perception of HYTLO1, a hydrophobin abundantly secreted by Trichoderma longibrachiatum, which may play an important role in the early stages of the plant-fungus interaction. Aequorin-expressing Lotus japonicus suspension cell cultures responded to HYTLO1 with a rapid cytosolic Ca2+ increase that dissipated within 30 min, followed by the activation of the defence-related genes MPK3, WRK33, and CP450. The Ca2+-dependence of these gene expression was demonstrated by using the extracellular Ca2+ chelator EGTA and Ned-19, a potent inhibitor of the nicotinic acid adenine dinucleotide phosphate (NAADP) receptor in animal cells, which effectively blocked the HYTLO1-induced Ca2+ elevation. Immunocytochemical analyses showed the localization of the fungal hydrophobin at the plant cell surface, where it forms a protein film covering the plant cell wall. Our data demonstrate the Ca2+-mediated perception by plant cells of a key metabolite secreted by a biocontrol fungus, and provide the first evidence of the involvement of NAADP-gated Ca2+ release in a signalling pathway triggered by a biotic stimulus.
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Affiliation(s)
- Roberto Moscatiello
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
| | - Simone Sello
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
| | - Michelina Ruocco
- Institute for Sustainable Plant Protection, CNR, Via Università 133, 80055 Portici (NA), Italy.
| | - Ani Barbulova
- Institute of BioSciences and BioResourses, CNR, Via P. Castellino 111, 80131 Napoli, Italy.
| | - Enrico Cortese
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
| | - Sebastiano Nigris
- Botanical Garden, University of Padova, Via Orto Botanico 15, 35123 Padova, Italy.
| | - Barbara Baldan
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
- Botanical Garden, University of Padova, Via Orto Botanico 15, 35123 Padova, Italy.
| | - Maurizio Chiurazzi
- Institute of BioSciences and BioResourses, CNR, Via P. Castellino 111, 80131 Napoli, Italy.
| | - Paola Mariani
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
| | - Matteo Lorito
- Department of Agricultural Sciences, University of Napoli "Federico II", Via Università 100, 80055 Portici (NA), Italy.
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy.
- Botanical Garden, University of Padova, Via Orto Botanico 15, 35123 Padova, Italy.
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13
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Costa A, Navazio L, Szabo I. The contribution of organelles to plant intracellular Calcium signalling. J Exp Bot 2018; 69:4996169. [PMID: 29767757 DOI: 10.1093/jxb/ery185] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 05/18/2023]
Abstract
Calcium (Ca2+) is among the most important intracellular messengers in living organisms. Understanding of the players and dynamics of Ca2+ signalling pathways in plants may help to unravel the molecular basis of their exceptional flexibility to respond and to adapt to different stimuli. In the present review we focus on new tools that have recently revolutionized our view of organellar Ca2+ signalling as well as on the current knowledge regarding the pathways mediating Ca2+ fluxes across intracellular membranes. The contribution of organelles and cellular subcompartments to the orchestrated response via Ca2+ signalling within a cell is also discussed, underlining the fact that one of the greatest challenges in the field is the elucidation of how influx and efflux Ca2+ transporters/channels are regulated in a concerted manner to translate specific information into a Ca2+ signature.
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Affiliation(s)
- Alex Costa
- Department of Biosciences, University of Milan, Via G. Celoria, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Via G. Celoria, Milan, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi, Padova, Italy
- Botanical Garden, University of Padova, Via Orto Botanico, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Via U. Bassi, Padova, Italy
- Botanical Garden, University of Padova, Via Orto Botanico, Padova, Italy
- Institute of Neurosciences, Consiglio Nazionale delle Ricerche, Via U. Bassi, Padova, Italy
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14
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Sello S, Moscatiello R, Mehlmer N, Leonardelli M, Carraretto L, Cortese E, Zanella FG, Baldan B, Szabò I, Vothknecht UC, Navazio L. Chloroplast Ca 2+ Fluxes into and across Thylakoids Revealed by Thylakoid-Targeted Aequorin Probes. Plant Physiol 2018; 177:38-51. [PMID: 29559589 PMCID: PMC5933129 DOI: 10.1104/pp.18.00027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/05/2018] [Indexed: 05/18/2023]
Abstract
Chloroplasts require a fine-tuned control of their internal Ca2+ concentration, which is crucial for many aspects of photosynthesis and for other chloroplast-localized processes. Increasing evidence suggests that calcium regulation within chloroplasts also may influence Ca2+ signaling pathways in the cytosol. To investigate the involvement of thylakoids in Ca2+ homeostasis and in the modulation of chloroplast Ca2+ signals in vivo, we targeted the bioluminescent Ca2+ reporter aequorin as a YFP fusion to the lumen and the stromal surface of thylakoids in Arabidopsis (Arabidopsis thaliana). Thylakoid localization of aequorin-based probes in stably transformed lines was confirmed by confocal microscopy, immunogold labeling, and biochemical analyses. In resting conditions in the dark, free Ca2+ levels in the thylakoid lumen were maintained at about 0.5 μm, which was a 3- to 5-fold higher concentration than in the stroma. Monitoring of chloroplast Ca2+ dynamics in different intrachloroplast subcompartments (stroma, thylakoid membrane, and thylakoid lumen) revealed the occurrence of stimulus-specific Ca2+ signals, characterized by unique kinetic parameters. Oxidative and salt stresses initiated pronounced free Ca2+ changes in the thylakoid lumen. Localized Ca2+ increases also were observed on the thylakoid membrane surface, mirroring transient Ca2+ changes observed for the bulk stroma, but with specific Ca2+ dynamics. Moreover, evidence was obtained for dark-stimulated intrathylakoid Ca2+ changes, suggesting a new scenario for light-to-dark-induced Ca2+ fluxes inside chloroplasts. Hence, thylakoid-targeted aequorin reporters can provide new insights into chloroplast Ca2+ storage and signal transduction. These probes represent novel tools with which to investigate the role of thylakoids in Ca2+ signaling networks within chloroplasts and plant cells.
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Affiliation(s)
- Simone Sello
- Department of Biology, University of Padova, 35131 Padova, Italy
| | | | - Norbert Mehlmer
- Department of Biology I, Faculty of Biology, LMU Munich, D-82152 Munich, Germany
| | - Manuela Leonardelli
- Department of Biology, University of Padova, 35131 Padova, Italy
- Department of Biology I, Faculty of Biology, LMU Munich, D-82152 Munich, Germany
| | - Luca Carraretto
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Enrico Cortese
- Department of Biology, University of Padova, 35131 Padova, Italy
| | | | - Barbara Baldan
- Department of Biology, University of Padova, 35131 Padova, Italy
- Botanical Garden, University of Padova, 35123 Padova, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padova, 35131 Padova, Italy
- Botanical Garden, University of Padova, 35123 Padova, Italy
| | - Ute C Vothknecht
- Department of Biology I, Faculty of Biology, LMU Munich, D-82152 Munich, Germany
- Plant Cell Biology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Lorella Navazio
- Department of Biology, University of Padova, 35131 Padova, Italy
- Botanical Garden, University of Padova, 35123 Padova, Italy
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15
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Busatto N, Salvagnin U, Resentini F, Quaresimin S, Navazio L, Marin O, Pellegrini M, Costa F, Mierke DF, Trainotti L. The Peach RGF/GLV Signaling Peptide pCTG134 Is Involved in a Regulatory Circuit That Sustains Auxin and Ethylene Actions. Front Plant Sci 2017; 8:1711. [PMID: 29075273 PMCID: PMC5641559 DOI: 10.3389/fpls.2017.01711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/19/2017] [Indexed: 05/24/2023]
Abstract
In vascular plants the cell-to-cell interactions coordinating morphogenetic and physiological processes are mediated, among others, by the action of hormones, among which also short mobile peptides were recognized to have roles as signals. Such peptide hormones (PHs) are involved in defense responses, shoot and root growth, meristem homeostasis, organ abscission, nutrient signaling, hormone crosstalk and other developmental processes and act as both short and long distant ligands. In this work, the function of CTG134, a peach gene encoding a ROOT GROWTH FACTOR/GOLVEN-like PH expressed in mesocarp at the onset of ripening, was investigated for its role in mediating an auxin-ethylene crosstalk. In peach fruit, where an auxin-ethylene crosstalk mechanism is necessary to support climacteric ethylene synthesis, CTG134 expression peaked before that of ACS1 and was induced by auxin and 1-methylcyclopropene (1-MCP) treatments, whereas it was minimally affected by ethylene. In addition, the promoter of CTG134 fused with the GUS reporter highlighted activity in plant parts in which the auxin-ethylene interplay is known to occur. Arabidopsis and tobacco plants overexpressing CTG134 showed abnormal root hair growth, similar to wild-type plants treated with a synthetic form of the sulfated peptide. Moreover, in tobacco, lateral root emergence and capsule size were also affected. In Arabidopsis overexpressing lines, molecular surveys demonstrated an impaired hormonal crosstalk, resulting in a re-modulated expression of a set of genes involved in both ethylene and auxin synthesis, transport and perception. These data support the role of pCTG134 as a mediator in an auxin-ethylene regulatory circuit and open the possibility to exploit this class of ligands for the rational design of new and environmental friendly agrochemicals able to cope with a rapidly changing environment.
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Affiliation(s)
- Nicola Busatto
- Department of Biology, University of Padova, Padova, Italy
- Department of Genomics and Crop Biology, Research and Innovation Centre, Fondazione Edmund Mach, Trento, Italy
| | | | | | | | | | - Oriano Marin
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Maria Pellegrini
- Department of Chemistry, Dartmouth College, Hanover, NH, United States
| | - Fabrizio Costa
- Department of Genomics and Crop Biology, Research and Innovation Centre, Fondazione Edmund Mach, Trento, Italy
| | - Dale F. Mierke
- Department of Chemistry, Dartmouth College, Hanover, NH, United States
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16
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Aloisi I, Cai G, Faleri C, Navazio L, Serafini-Fracassini D, Del Duca S. Spermine Regulates Pollen Tube Growth by Modulating Ca 2+-Dependent Actin Organization and Cell Wall Structure. Front Plant Sci 2017; 8:1701. [PMID: 29033970 PMCID: PMC5627395 DOI: 10.3389/fpls.2017.01701] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/15/2017] [Indexed: 05/25/2023]
Abstract
Proper growth of the pollen tube depends on an elaborate mechanism that integrates several molecular and cytological sub-processes and ensures a cell shape adapted to the transport of gametes. This growth mechanism is controlled by several molecules among which cytoplasmic and apoplastic polyamines. Spermine (Spm) has been correlated with various physiological processes in pollen, including structuring of the cell wall and modulation of protein (mainly cytoskeletal) assembly. In this work, the effects of Spm on the growth of pear pollen tubes were analyzed. When exogenous Spm (100 μM) was supplied to germinating pollen, it temporarily blocked tube growth, followed by the induction of apical swelling. This reshaping of the pollen tube was maintained also after growth recovery, leading to a 30-40% increase of tube diameter. Apical swelling was also accompanied by a transient increase in cytosolic calcium concentration and alteration of pH values, which were the likely cause for major reorganization of actin filaments and cytoplasmic organelle movement. Morphological alterations of the apical and subapical region also involved changes in the deposition of pectin, cellulose, and callose in the cell wall. Thus, results point to the involvement of Spm in cell wall construction as well as cytoskeleton organization during pear pollen tube growth.
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Affiliation(s)
- Iris Aloisi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Claudia Faleri
- Department of Life Sciences, University of Siena, Siena, Italy
| | | | | | - Stefano Del Duca
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
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17
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Sello S, Moscatiello R, La Rocca N, Baldan B, Navazio L. A Rapid and Efficient Method to Obtain Photosynthetic Cell Suspension Cultures of Arabidopsis thaliana. Front Plant Sci 2017; 8:1444. [PMID: 28868063 PMCID: PMC5563381 DOI: 10.3389/fpls.2017.01444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 08/03/2017] [Indexed: 05/29/2023]
Abstract
Photosynthetic cell suspension cultures are a useful experimental system to analyze a variety of physiological processes, bypassing the structural complexity of the plant organism in toto. Nevertheless, cell cultures containing functional chloroplasts are quite difficult to obtain, and this process is usually laborious and time-consuming. In this work a novel and rapid method to set up photosynthetic cell suspension cultures from the model plant Arabidopsis thaliana was developed. The direct germination of Arabidopsis seeds on a sucrose-containing agarized culture medium supplemented with 0.25 μg/ml 6-benzylaminopurine and 0.5 μg/ml 2,4-dichlorophenoxyacetic acid caused the straightforward formation of green calli at the level of seedling hypocotyls. The subsequent transfer of these calli in liquid culture medium containing the same concentrations of phytohormones and gradually decreasing sucrose levels allowed for the establishment of chloroplast-containing cell suspension cultures, containing functional chloroplasts, in a much faster way than previously described procedures. Pulse amplitude modulation analyses, measurements of oxygen evolution and electron transport rate, together with confocal and electron microscopy observations, confirmed the photosynthetic efficiency of these cell suspension cultures. The described procedure lends itself as a simple and effective way to obtain a convenient tool for a wide array of structural and functional studies on chloroplasts.
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Affiliation(s)
- Simone Sello
- Department of Biology, University of PadovaPadova, Italy
| | | | | | - Barbara Baldan
- Department of Biology, University of PadovaPadova, Italy
- Botanical Garden, University of PadovaPadova, Italy
| | - Lorella Navazio
- Department of Biology, University of PadovaPadova, Italy
- Botanical Garden, University of PadovaPadova, Italy
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18
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Sello S, Perotto J, Carraretto L, Szabò I, Vothknecht UC, Navazio L. Dissecting stimulus-specific Ca2+ signals in amyloplasts and chloroplasts of Arabidopsis thaliana cell suspension cultures. J Exp Bot 2016; 67:3965-74. [PMID: 26893493 PMCID: PMC4915524 DOI: 10.1093/jxb/erw038] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Calcium is used by plants as an intracellular messenger in the detection of and response to a plethora of environmental stimuli and contributes to a fine-tuned internal regulation. Interest in the role of different subcellular compartments in Ca(2+) homeostasis and signalling has been growing in recent years. This work has evaluated the potential participation of non-green plastids and chloroplasts in the plant Ca(2+) signalling network using heterotrophic and autotrophic cell suspension cultures from Arabidopsis thaliana plant lines stably expressing the bioluminescent Ca(2+) reporter aequorin targeted to the plastid stroma. Our results indicate that both amyloplasts and chloroplasts are involved in transient Ca(2+) increases in the plastid stroma induced by several environmental stimuli, suggesting that these two functional types of plastids are endowed with similar mechanisms for handling Ca(2+) A comparison of the Ca(2+) trace kinetics recorded in parallel in the plastid stroma, the surface of the outer membrane of the plastid envelope, and the cytosol indicated that plastids play an essential role in switching off different cytosolic Ca(2+) signals. Interestingly, a transient stromal Ca(2+) signal in response to the light-to-dark transition was observed in chloroplasts, but not amyloplasts. Moreover, significant differences in the amplitude of specific plastidial Ca(2+) changes emerged when the photosynthetic metabolism of chloroplasts was reactivated by light. In summary, our work highlights differences between non-green plastids and chloroplasts in terms of Ca(2+) dynamics in response to environmental stimuli.
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Affiliation(s)
- Simone Sello
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Jennifer Perotto
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Ute C Vothknecht
- Department of Biology I, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, D-82152 Munich, Germany
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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19
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Salvioli A, Ghignone S, Novero M, Navazio L, Venice F, Bagnaresi P, Bonfante P. Symbiosis with an endobacterium increases the fitness of a mycorrhizal fungus, raising its bioenergetic potential. ISME J 2016; 10:130-44. [PMID: 26046255 PMCID: PMC4681866 DOI: 10.1038/ismej.2015.91] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/27/2015] [Accepted: 04/21/2015] [Indexed: 01/08/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) occur in the rhizosphere and in plant tissues as obligate symbionts, having key roles in plant evolution and nutrition. AMF possess endobacteria, and genome sequencing of the endobacterium Candidatus Glomeribacter gigasporarum revealed a reduced genome and a dependence on the fungal host. To understand the effect of bacteria on fungal fitness, we used next-generation sequencing to analyse the transcriptional profile of Gigaspora margarita in the presence and in the absence of its endobacterium. Genomic data on AMF are limited; therefore, we first generated a gene catalogue for G. margarita. Transcriptome analysis revealed that the endobacterium has a stronger effect on the pre-symbiotic phase of the fungus. Coupling transcriptomics with cell biology and physiological approaches, we demonstrate that the bacterium increases the fungal sporulation success, raises the fungal bioenergetic capacity, increasing ATP production, and eliciting mechanisms to detoxify reactive oxygen species. By using TAT peptide to translocate the bioluminescent calcium reporter aequorin, we demonstrated that the line with endobacteria had a lower basal intracellular calcium concentration than the cured line. Lastly, the bacteria seem to enhance the fungal responsiveness to strigolactones, the plant molecules that AMF perceive as branching factors. Although the endobacterium exacts a nutritional cost on the AMF, endobacterial symbiosis improves the fungal ecological fitness by priming mitochondrial metabolic pathways and giving the AMF more tools to face environmental stresses. Thus, we hypothesise that, as described for the human microbiota, endobacteria may increase AMF innate immunity.
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Affiliation(s)
- Alessandra Salvioli
- Department of Life Science and Systems Biology, University of Torino, Torino, Italy
| | - Stefano Ghignone
- Institute for Sustainable Plant Protection (IPSP) – CNR, Torino, Italy
| | - Mara Novero
- Department of Life Science and Systems Biology, University of Torino, Torino, Italy
| | | | - Francesco Venice
- Department of Life Science and Systems Biology, University of Torino, Torino, Italy
| | - Paolo Bagnaresi
- Research Center for Genomics and Postgenomics, CRA-Fiorenzuola d'Arda, Italy
| | - Paola Bonfante
- Department of Life Science and Systems Biology, University of Torino, Torino, Italy
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20
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Wagner S, Behera S, De Bortoli S, Logan DC, Fuchs P, Carraretto L, Teardo E, Cendron L, Nietzel T, Füßl M, Doccula FG, Navazio L, Fricker MD, Van Aken O, Finkemeier I, Meyer AJ, Szabò I, Costa A, Schwarzländer M. The EF-Hand Ca2+ Binding Protein MICU Choreographs Mitochondrial Ca2+ Dynamics in Arabidopsis. Plant Cell 2015; 27:3190-212. [PMID: 26530087 PMCID: PMC4682298 DOI: 10.1105/tpc.15.00509] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/25/2015] [Accepted: 10/15/2015] [Indexed: 05/18/2023]
Abstract
Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca(2+) signaling may play a central role in this process. Free Ca(2+) dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca(2+) dynamics is poorly understood. Here, we studied the function of At-MICU, an EF-hand protein of Arabidopsis thaliana with homology to constituents of the mitochondrial Ca(2+) uniporter machinery in mammals. MICU binds Ca(2+) and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca(2+) sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca(2+) in the matrix. Furthermore, Ca(2+) elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca(2+) signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca(2+) uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca(2+) uptake by moderating influx, thereby shaping Ca(2+) signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca(2+) signaling in plants.
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Affiliation(s)
- Stephan Wagner
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | | | - Sara De Bortoli
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - David C Logan
- Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences, F-49045 Angers, France
| | - Philippe Fuchs
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Luca Carraretto
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Thomas Nietzel
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Magdalena Füßl
- Plant Proteomics Group, Max-Planck-Institute for Plant Breeding Research, 50829 Cologne, Germany
| | | | - Lorella Navazio
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Mark D Fricker
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - Iris Finkemeier
- Plant Proteomics Group, Max-Planck-Institute for Plant Breeding Research, 50829 Cologne, Germany Institute for Plant Biology and Biotechnology, University of Münster, 48149 Münster, Germany
| | - Andreas J Meyer
- Department Chemical Signalling, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Ildikò Szabò
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milan, Italy Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy
| | - Markus Schwarzländer
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
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21
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Moscatiello R, Zaccarin M, Ercolin F, Damiani E, Squartini A, Roveri A, Navazio L. Identification of ferredoxin II as a major calcium binding protein in the nitrogen-fixing symbiotic bacterium Mesorhizobium loti. BMC Microbiol 2015; 15:16. [PMID: 25648224 PMCID: PMC4322793 DOI: 10.1186/s12866-015-0352-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Legumes establish with rhizobial bacteria a nitrogen-fixing symbiosis which is of the utmost importance for both plant nutrition and a sustainable agriculture. Calcium is known to act as a key intracellular messenger in the perception of symbiotic signals by both the host plant and the microbial partner. Regulation of intracellular free Ca(2+) concentration, which is a fundamental prerequisite for any Ca(2+)-based signalling system, is accomplished by complex mechanisms including Ca(2+) binding proteins acting as Ca(2+) buffers. In this work we investigated the occurrence of Ca(2+) binding proteins in Mesorhizobium loti, the specific symbiotic partner of the model legume Lotus japonicus. RESULTS A soluble, low molecular weight protein was found to share several biochemical features with the eukaryotic Ca(2+)-binding proteins calsequestrin and calreticulin, such as Stains-all blue staining on SDS-PAGE, an acidic isoelectric point and a Ca(2+)-dependent shift of electrophoretic mobility. The protein was purified to homogeneity by an ammonium sulfate precipitation procedure followed by anion-exchange chromatography on DEAE-Cellulose and electroendosmotic preparative electrophoresis. The Ca(2+) binding ability of the M. loti protein was demonstrated by (45)Ca(2+)-overlay assays. ESI-Q-TOF MS/MS analyses of the peptides generated after digestion with either trypsin or endoproteinase AspN identified the rhizobial protein as ferredoxin II and confirmed the presence of Ca(2+) adducts. CONCLUSIONS The present data indicate that ferredoxin II is a major Ca(2+) binding protein in M. loti that may participate in Ca(2+) homeostasis and suggest an evolutionarily ancient origin for protein-based Ca(2+) regulatory systems.
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Affiliation(s)
- Roberto Moscatiello
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131, Padova, Italy.
| | - Mattia Zaccarin
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, 35131, Padova, Italy.
| | - Flavia Ercolin
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131, Padova, Italy.
| | - Ernesto Damiani
- Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, 35131, Padova, Italy.
| | - Andrea Squartini
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, University of Padova, Viale dell'Università 16, 35020, Legnaro, Padova, Italy.
| | - Antonella Roveri
- Department of Molecular Medicine, University of Padova, Viale G. Colombo 3, 35131, Padova, Italy.
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131, Padova, Italy.
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Moscatiello R, Sello S, Novero M, Negro A, Bonfante P, Navazio L. The intracellular delivery of TAT-aequorin reveals calcium-mediated sensing of environmental and symbiotic signals by the arbuscular mycorrhizal fungus Gigaspora margarita. New Phytol 2014; 203:1012-1020. [PMID: 24845011 DOI: 10.1111/nph.12849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/10/2014] [Indexed: 06/03/2023]
Abstract
Arbuscular mycorrhiza (AM) is an ecologically relevant symbiosis between most land plants and Glomeromycota fungi. The peculiar traits of AM fungi have so far limited traditional approaches such as genetic transformation. The aim of this work was to investigate whether the protein transduction domain of the HIV-1 transactivator of transcription (TAT) protein, previously shown to act as a potent nanocarrier for macromolecule delivery in both animal and plant cells, may translocate protein cargoes into AM fungi. We evaluated the internalization into germinated spores of Gigaspora margarita of two recombinant TAT fusion proteins consisting of either a fluorescent (GFP) or a luminescent (aequorin) reporter linked to the TAT peptide. Both TAT-fused proteins were found to enter AM fungal mycelia after a short incubation period (5-10 min). Ca2+ measurements in G. margarita mycelia pre-incubated with TAT-aequorin demonstrated the occurrence of changes in the intracellular free Ca2+ concentration in response to relevant stimuli, such as touch, cold, salinity, and strigolactones, symbiosis-related plant signals. These data indicate that the cell-penetrating properties of the TAT peptide can be used as an effective strategy for intracellularly delivering proteins of interest and shed new light on Ca2+ homeostasis and signalling in AM fungi.
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Affiliation(s)
- Roberto Moscatiello
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131, Padova, Italy
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Nardi MC, Giacomelli E, Dainese P, Fitchette-Lainé AC, Faye L, Baldan B, Navazio L, Mariani P. Ginkgo bilobaExpresses Calreticulin, the Major Calcium-Binding Reticuloplasmin in Eukaryotic Cells. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1998.tb00679.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Arrigoni G, Tolin S, Moscatiello R, Masi A, Navazio L, Squartini A. Calcium-dependent regulation of genes for plant nodulation in Rhizobium leguminosarum detected by iTRAQ quantitative proteomic analysis. J Proteome Res 2013; 12:5323-30. [PMID: 24041410 DOI: 10.1021/pr400656g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rhizobia, the nitrogen-fixing bacterial symbionts of legumes, represent an agricultural application of primary relevance and a model of plant-microbe molecular dialogues. We recently described rhizobium proteome alterations induced by plant flavonoids using iTRAQ. Herein, we further extend that experimentation, proving that the transient elevation in cytosolic calcium is a key signaling event necessary for the expression of the nodulation (nod) genes. Ca(2+) involvement in nodulation is a novel issue that we recently flagged with genetic and physiological approaches and that hereby we demonstrate also by proteomics. Exploiting the multiple combinations of 4-plex iTRAQ, we analyzed Rhizobium leguminosarum cultures grown with or without the nod gene-inducing plant flavonoid naringenin and in the presence or absence of the extracellular Ca(2+) chelator EGTA. We quantified over a thousand proteins, 189 of which significantly altered upon naringenin and/or EGTA stimulation. The expression of NodA, highly induced by naringenin, is strongly reduced when calcium availability is limited by EGTA. This confirms, from a proteomic perspective, that a Ca(2+) influx is a necessary early step in flavonoid-mediated legume nodulation by rhizobia. We also observed other proteins affected by the different treatments, whose identities and roles in nodulation and rhizobium physiology are likewise discussed.
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Affiliation(s)
- Giorgio Arrigoni
- Proteomics Center of Padova University , Via G. Orus 2b, 35129 Padova, Italy
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Tolin S, Arrigoni G, Moscatiello R, Masi A, Navazio L, Sablok G, Squartini A. Quantitative analysis of the naringenin-inducible proteome in Rhizobium leguminosarum by isobaric tagging and mass spectrometry. Proteomics 2013; 13:1961-72. [PMID: 23580418 DOI: 10.1002/pmic.201200472] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 02/17/2013] [Accepted: 03/12/2013] [Indexed: 11/05/2022]
Abstract
The rhizobium-legume interaction is a critical cornerstone of crop productivity and environmental sustainability. Its potential improvement relies on elucidation of the complex molecular dialogue between its two partners. In the present study, the proteomic patterns of gnotobiotic cultures of Rhizobium leguminosarum bv. viciae 3841 grown for 6 h in presence or absence of the nod gene-inducing plant flavonoid naringenin (10 μM) were analyzed using the iTRAQ approach. A total of 1334 proteins were identified corresponding to 18.67% of the protein-coding genes annotated in the sequenced genome of bv. viciae 3841. The abundance levels of 47 proteins were increased upon naringenin treatment showing fold change ratios ranging from 1.5 to 25 in two biological replicates. Besides the nod units, naringenin enhanced the expression of a number of other genes, many of which organized in operons, including β(1-2) glucan production and secretion, succinoglycan export, the RopA outer membrane protein with homology to an oligogalacturonide-specific porin motif, other enzymes for carbohydrate and amino acid metabolism, and proteins involved in the translation machinery. Data were validated at the transcriptional and phenotypic levels by RT-PCR and an assay of secreted sugars in culture supernatants, respectively. The current approach provides not only a high-resolution analysis of the prokaryotic proteome but also unravels the rhizobium molecular dialogue with legumes by detecting the enhanced expression of several symbiosis-associated proteins, whose flavonoid-dependency had not yet been reported.
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Affiliation(s)
- Serena Tolin
- Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, Legnaro, Padova, Italy
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Abstract
Plant cell suspension cultures are widely used in plant biology as a convenient tool for the investigation of a wide range of phenomena, bypassing the structural complexity of the plant organism in toto. The homogeneity of an in vitro cell population, the large availability of material, the high rate of cell growth and the good reproducibility of conditions make suspension-cultured cells suitable for the analysis of complex physiological processes at the cellular and molecular levels. Moreover, plant cell cultures provide a valuable platform for the production of high-value secondary metabolites and other substances of commercial interest. Here we describe how to initiate and maintain plant cell cultures starting from explants obtained from in vitro germinated seedlings. Isolation of protoplasts from plant cell suspension cultures and regeneration of plants via organogenesis and somatic embryogenesis are also presented.
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Moscatiello R, Baldan B, Squartini A, Mariani P, Navazio L. Oligogalacturonides: novel signaling molecules in Rhizobium-legume communications. Mol Plant Microbe Interact 2012; 25:1387-1395. [PMID: 22835276 DOI: 10.1094/mpmi-03-12-0066-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Oligogalacturonides are pectic fragments of the plant cell wall, whose signaling role has been described thus far during plant development and plant-pathogen interactions. In the present work, we evaluated the potential involvement of oligogalacturonides in the molecular communications between legumes and rhizobia during the establishment of nitrogen-fixing symbiosis. Oligogalacturonides with a degree of polymerization of 10 to 15 were found to trigger a rapid intracellular production of reactive oxygen species in Rhizobium leguminosarum bv. viciae 3841. Accumulation of H(2)O(2), detected by both 2',7'-dichlorodihydrofluorescein diacetate-based fluorescence and electron-dense deposits of cerium perhydroxides, was transient and did not affect bacterial cell viability, due to the prompt activation of the katG gene encoding a catalase. Calcium measurements carried out in R. leguminosarum transformed with the bioluminescent Ca(2+) reporter aequorin demonstrated the induction of a rapid and remarkable intracellular Ca(2+) increase in response to oligogalacturonides. When applied jointly with naringenin, oligogalacturonides effectively inhibited flavonoid-induced nod gene expression, indicating an antagonistic interplay between oligogalacturonides and inducing flavonoids in the early stages of plant root colonization. The above data suggest a novel role for oligogalacturonides as signaling molecules released in the rhizosphere in the initial rhizobium-legume interaction.
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Zonin E, Moscatiello R, Miuzzo M, Cavallarin N, Di Paolo ML, Sandonà D, Marin O, Brini M, Negro A, Navazio L. TAT-mediated aequorin transduction: an alternative approach for effective calcium measurements in plant cells. Plant Cell Physiol 2011; 52:2225-35. [PMID: 22025557 DOI: 10.1093/pcp/pcr145] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cell-penetrating peptides are short cationic peptides with the property of translocating across the plasma membrane and transferring macromolecules otherwise unable to permeate cell membranes. We investigated the potential ability of the protein transduction domain derived from amino acids 47-57 of the human immunodeficiency virus type 1 (HIV-1) TAT (transactivator of transcription) protein to be used as a nanocarrier for the delivery of aequorin, a Ca(2+)-sensitive photoprotein widely used as a reliable Ca(2+) reporter in cell populations. The TAT peptide, either covalently linked to apoaequorin or ionically bound to plasmids encoding differentially targeted aequorin, was supplied to plant suspension-cultured cells. The TAT-aequorin fusion protein was found to be rapidly and effectively translocated into plant cells. The chimeric molecule was internalized in fully active biological form and at levels suitable to monitor intracellular Ca(2+) concentrations. Plant cells incubated for just 5 min with TAT-aequorin responded to different environmental stimuli with the expected Ca(2+) signatures. On the other hand, TAT-mediated plasmid internalization did not provide the necessary level of transformation efficiency to allow calibration of luminescence signals into Ca(2+) concentration values. These results indicate that TAT-mediated aequorin transduction is a promising alternative to traditional plant transformation methods to monitor intracellular Ca(2+) dynamics rapidly and effectively in plant cells.
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Affiliation(s)
- Elisabetta Zonin
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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Abstract
• Legume-rhizobium symbiosis requires a complex dialogue based on the exchange of diffusible signals between the partners. Compatible rhizobia express key nodulation (nod) genes in response to plant signals - flavonoids - before infection. Host plants sense counterpart rhizobial signalling molecules - Nod factors - through transient changes in intracellular free-calcium. Here we investigate the potential involvement of Ca(2+) in the symbiotic signalling pathway activated by flavonoids in Rhizobium leguminosarum bv. viciae. • By using aequorin-expressing rhizobial strains, we monitored intracellular Ca(2+) dynamics and the Ca(2+) dependence of nod gene transcriptional activation. • Flavonoid inducers triggered, in R. leguminosarum, transient increases in the concentration of intracellular Ca(2+) that were essential for the induction of nod genes. Signalling molecules not specifically related to rhizobia, such as strigolactones, were not perceived by rhizobia through Ca(2+) variations. A Rhizobium strain cured of the symbiotic plasmid responded to inducers with an unchanged Ca(2+) signature, showing that the transcriptional regulator NodD is not directly involved in this stage of flavonoid perception and plays its role downstream of the Ca(2+) signalling event. • These findings demonstrate a key role played by Ca(2+) in sensing and transducing plant-specific flavonoid signals in rhizobia and open up a new perspective in the flavonoid-NodD paradigm of nod gene regulation.
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Baldan B, Andolfo P, Navazio L, Tolomio C, Mariani P. Cellulose in algal cell wall : an “in situ” localization. Eur J Histochem 2009. [DOI: 10.4081/1613] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Moscatiello R, Alberghini S, Squartini A, Mariani P, Navazio L. Evidence for calcium-mediated perception of plant symbiotic signals in aequorin-expressing Mesorhizobium loti. BMC Microbiol 2009; 9:206. [PMID: 19775463 PMCID: PMC2759959 DOI: 10.1186/1471-2180-9-206] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 09/23/2009] [Indexed: 11/22/2022] Open
Abstract
Background During the interaction between rhizobia and leguminous plants the two partners engage in a molecular conversation that leads to reciprocal recognition and ensures the beginning of a successful symbiotic integration. In host plants, intracellular Ca2+ changes are an integral part of the signalling mechanism. In rhizobia it is not yet known whether Ca2+ can act as a transducer of symbiotic signals. Results A plasmid encoding the bioluminescent Ca2+ probe aequorin was introduced into Mesorhizobium loti USDA 3147T strain to investigate whether a Ca2+ response is activated in rhizobia upon perception of plant root exudates. We find that M. loti cells respond to environmental and symbiotic cues through transient elevations in intracellular free Ca2+ concentration. Only root exudates from the homologous host Lotus japonicus induce Ca2+ signalling and downstream activation of nodulation genes. The extracellular Ca2+ chelator EGTA inhibits both transient intracellular Ca2+ increase and inducible nod gene expression, while not affecting the expression of other genes, either constitutively expressed or inducible. Conclusion These findings indicate a newly described early event in the molecular dialogue between plants and rhizobia and highlight the use of aequorin-expressing bacterial strains as a promising novel approach for research in legume symbiosis.
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Affiliation(s)
- Roberto Moscatiello
- Dipartimento di Biologia, Università di Padova, Via U, Bassi 58/B, 35131 Padova, Italy.
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Navazio L, Mariani P. Calcium opens the dialogue between plants and arbuscular mycorrhizal fungi. Plant Signal Behav 2008; 3:229-30. [PMID: 19704636 PMCID: PMC2634184 DOI: 10.4161/psb.3.4.5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 09/27/2007] [Indexed: 05/14/2023]
Abstract
Calcium ion is considered a ubiquitous second messenger in all eukaryotic cells. Analysis of intracellular Ca(2+) concentration dynamics has demonstrated its signalling role in plant cells in response to a wide array of environmental cues. The implication of Ca(2+) in the early steps of the arbuscular mycorrhizal symbiosis has been frequently claimed, mainly by analogy with what firmly demonstrated in the rhizobium-legume symbiosis. We recently documented transient Ca(2+) changes in plant cells challenged with diffusible molecules released by arbuscular mycorrhizal fungi. Ca(2+) measurements by the recombinant aequorin method provided new insights into the molecular communications between plants and these beneficial fungi.
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Affiliation(s)
- Lorella Navazio
- Dipartimento di Biologia; Università di Padova; Padova, Italy
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Navazio L, Baldan B, Moscatiello R, Zuppini A, Woo SL, Mariani P, Lorito M. Calcium-mediated perception and defense responses activated in plant cells by metabolite mixtures secreted by the biocontrol fungus Trichoderma atroviride. BMC Plant Biol 2007; 7:41. [PMID: 17663762 PMCID: PMC1950503 DOI: 10.1186/1471-2229-7-41] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 07/30/2007] [Indexed: 05/07/2023]
Abstract
BACKGROUND Calcium is commonly involved as intracellular messenger in the transduction by plants of a wide range of biotic stimuli, including signals from pathogenic and symbiotic fungi. Trichoderma spp. are largely used in the biological control of plant diseases caused by fungal phytopathogens and are able to colonize plant roots. Early molecular events underlying their association with plants are relatively unknown. RESULTS Here, we investigated the effects on plant cells of metabolite complexes secreted by Trichoderma atroviride wild type P1 and a deletion mutant of this strain on the level of cytosolic free Ca2+ and activation of defense responses. Trichoderma culture filtrates were obtained by growing the fungus alone or in direct antagonism with its fungal host, the necrotrophic pathogen Botrytis cinerea, and then separated in two fractions (>3 and <3 kDa). When applied to aequorin-expressing soybean (Glycine max L.) cell suspension cultures, Trichoderma and Botrytis metabolite mixtures were distinctively perceived and activated transient intracellular Ca2+ elevations with different kinetics, specific patterns of intracellular accumulation of reactive oxygen species and induction of cell death. Both Ca2+ signature and cellular effects were modified by the culture medium from the knock-out mutant of Trichoderma, defective for the production of the secreted 42 kDa endochitinase. CONCLUSION New insights are provided into the mechanism of interaction between Trichoderma and plants, indicating that secreted fungal molecules are sensed by plant cells through intracellular Ca2+ changes. Plant cells are able to discriminate signals originating in the single or two-fungal partner interaction and modulate defense responses.
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Affiliation(s)
- Lorella Navazio
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Barbara Baldan
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Roberto Moscatiello
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Anna Zuppini
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Sheridan L Woo
- Dipartimento di Arboricoltura, Botanica e Patologia Vegetale, Università di Napoli "Federico II", Via Università 100, 80055 Portici (NA), Italy
| | - Paola Mariani
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Matteo Lorito
- Dipartimento di Arboricoltura, Botanica e Patologia Vegetale, Università di Napoli "Federico II", Via Università 100, 80055 Portici (NA), Italy
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Navazio L, Moscatiello R, Genre A, Novero M, Baldan B, Bonfante P, Mariani P. A diffusible signal from arbuscular mycorrhizal fungi elicits a transient cytosolic calcium elevation in host plant cells. Plant Physiol 2007; 144:673-81. [PMID: 17142489 PMCID: PMC1914206 DOI: 10.1104/pp.106.086959] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 11/21/2006] [Indexed: 05/12/2023]
Abstract
The implication of calcium as intracellular messenger in the arbuscular mycorrhizal (AM) symbiosis has not yet been directly demonstrated, although often envisaged. We used soybean (Glycine max) cell cultures stably expressing the bioluminescent Ca(2+) indicator aequorin to detect intracellular Ca(2+) changes in response to the culture medium of spores of Gigaspora margarita germinating in the absence of the plant partner. Rapid and transient elevations in cytosolic free Ca(2+) were recorded, indicating that diffusible molecules released by the mycorrhizal fungus are perceived by host plant cells through a Ca(2+)-mediated signaling. Similar responses were also triggered by two Glomus isolates. The fungal molecules active in generating the Ca(2+) transient were constitutively released in the medium, and the induced Ca(2+) signature was not modified by the coculture of germinating spores with plant cells. Even ungerminated spores were able to generate the signaling molecules, as proven when the germination was blocked by a low temperature. The fungal molecules were found to be stable to heat treatment, of small molecular mass (<3 kD), and, on the basis of extraction with an organic solvent, partially lipophilic. Evidence for the specificity of such an early fungal signal to the AM symbiosis is suggested by the lack of a Ca(2+) response in cultured cells of the nonhost plant Arabidopsis (Arabidopsis thaliana) and by the up-regulation in soybean cells of genes related to Medicago truncatula DMI1, DMI2, and DMI3 and considered essential for the establishment of the AM symbiosis.
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Affiliation(s)
- Lorella Navazio
- Dipartimento di Biologia, Università di Padova, 35131 Padova, Italy.
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Nardi MC, Feron R, Navazio L, Mariani P, Pierson E, Wolters-Arts M, Knuiman B, Mariani C, Derksen J. Expression and localization of calreticulin in tobacco anthers and pollen tubes. Planta 2006; 223:1263-71. [PMID: 16320066 DOI: 10.1007/s00425-005-0175-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2005] [Accepted: 10/01/2005] [Indexed: 05/05/2023]
Abstract
The developmental expression pattern and localization of calreticulin were studied in Nicotiana tabacum L. anthers, pollen and pollen tubes. High transcript and protein levels were detected throughout anther development. Immunolocalization of calreticulin in the anthers showed particular dense label in tapetum and pollen at developmental stage 2, when the tapetum is highly active and the pollen tetrads are formed. Much lower transcript and protein levels were detected in dry and hydrated pollen and in pollen tubes. Immunofluorescence labeling of both chemically fixed and cryo-fixed and freeze-substituted pollen tubes showed the presence of calreticulin in Golgi apparatus and endoplasmic reticulum (ER). Calreticulin was seen throughout the stacks in the Golgi apparatus and in the areas with coated-Golgi vesicles but much less so in the ER. Calreticulin was not found in the secretory vesicles. A relatively intense label was occasionally seen adjacent to the wall of the tube. No significant label was observed in mitochondria, vacuoles, generative cells, cell wall or callose plugs. The present results are consistent with a role of calreticulin in Ca2+-dependent folding of secreted glycoproteins in tapetum, pollen and pollen tubes.
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Affiliation(s)
- Maria Chiara Nardi
- Department of Plant Cell Biology, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Zuppini A, Navazio L, Sella L, Castiglioni C, Favaron F, Mariani P. An endopolygalacturonase from Sclerotinia sclerotiorum induces calcium-mediated signaling and programmed cell death in soybean cells. Mol Plant Microbe Interact 2005; 18:849-55. [PMID: 16134897 DOI: 10.1094/mpmi-18-0849] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A basic endopolygalacturonase (PG) isoform, produced early by Sclerotinia sclerotiorum when infecting soybean seedlings, was used to examine the signaling role of the enzyme in aequorin-expressing soybean cells. A cytosolic Ca2+ elevation was induced, with a rapid increase (phase 1) and a very slow decrease (phase 2) of Ca2+ concentration, indicating the involvement of Ca2+ ions in PG signaling. Within 1 h of PG-cell contact a remarkable level of cell death was recorded, significantly higher than the control cell culture turnover. The observed morphological and biochemical changes were indicative of the activation of programmed cell death; in particular, cytochrome c release in the cytoplasm and activation of both caspase 9-like and caspase 3-like proteases were found. When a polygalacturonase-inhibiting protein (PGIP) and the PG were simultaneously applied to cells, both the Ca2+ increase and cell death were annulled. The possible roles of prolonged sustained cytosolic Ca2+ concentrations in inducing cell death and of the PG-PGIP interaction in preventing PG signaling are discussed.
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Affiliation(s)
- Anna Zuppini
- Dipartimento di Biologia, Università di Padova, via U Bassi 58/B, 35131 Padova, Italy
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Abstract
In animal cells, the endoplasmic reticulum may participate in programmed cell death by sensing and transducing apoptotic signals. In an attempt to analyze the role of the endoplasmic reticulum in plant programmed cell death we investigated the effect of cyclopiazonic acid, a specific blocker of plant endoplasmic reticulum-type IIA Ca2+-pumps, in soybean cells. Cyclopiazonic acid treatment elicited endoplasmic reticulum stress and a biphasic increase in cytosolic Ca2+ concentration, followed by the induction of a cell death program. Cyclopiazonic acid-induced programmed cell death occurred with accumulation of H2O2, cytochrome c release from mitochondria, caspase 9- and caspase 3-like protease activation, cytoplasmic shrinkage and chromatin condensation. Chelation of cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (acetoxymethil ester) failed to inhibit cyclopiazonic acid-induced cell death. Taken together, our results provide evidence for a role of the endoplasmic reticulum and mitochondria in regulating cyclopiazonic acid-induced programmed cell death in soybean cells, probably via a cross-talk between the two organelles.
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Affiliation(s)
- Anna Zuppini
- Dipartimento di Biologia, Università di Padova, 35131 Padova, Italy.
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Zuppini A, Baldan B, Millioni R, Favaron F, Navazio L, Mariani P. Chitosan induces Ca 2+ -mediated programmed cell death in soybean cells. New Phytol 2004; 161:557-568. [PMID: 33873499 DOI: 10.1046/j.1469-8137.2003.00969.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
• Chitosan, a component of the cell wall of many fungi, has been widely used to mimic pathogen attack and has been shown to induce several defence responses. • Here we show that low concentrations (50 µg ml-1 ) of chitosan are able to induce an increase in cytosolic Ca2+ concentration ([Ca2+ ]cyt ), accumulation of H2 O2 in the culture medium, induction of the defence gene chalcone synthase (chs), and cell death in soybean cells (Glycine max). • Chitosan-induced cell death occurred through cytoplasmic shrinkage, chromatin condensation and activation of caspase 3-like protease, suggesting the activation of a programmed cell death (PCD) pathway. Buffering extracellular Ca2+ with the Ca2+ chelator EGTA prevents [Ca2+ ]cyt elevation, H2 O2 production and all downstream PCD features, but not cell death. • Higher doses (200 µg ml-1 ) of chitosan evoked neither Ca2+ transient and H2 O2 production nor caspase 3-like activation, but caused cell death, possibly as a result of plasma membrane disturbance.
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Affiliation(s)
- Anna Zuppini
- Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, 35131 Padova, Italy
| | - Barbara Baldan
- Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, 35131 Padova, Italy
| | - Renato Millioni
- Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, 35131 Padova, Italy
| | - Francesco Favaron
- Dipartimento Te. S.A.F., Sez. Patologia Vegetale, Università di Padova, str. Romea 16, 35020 Legnaro, Padova, Italy
| | - Lorella Navazio
- Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, 35131 Padova, Italy
| | - Paola Mariani
- Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, 35131 Padova, Italy
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Navazio L, Miuzzo M, Royle L, Baldan B, Varotto S, Merry AH, Harvey DJ, Dwek RA, Rudd PM, Mariani P. Monitoring endoplasmic reticulum-to-Golgi traffic of a plant calreticulin by protein glycosylation analysis. Biochemistry 2002; 41:14141-9. [PMID: 12450377 DOI: 10.1021/bi0204701] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Calreticulin is a ubiquitous and highly conserved Ca(2+)-binding protein that is involved in intracellular Ca(2+) homeostasis and molecular chaperoning in the endoplasmic reticulum (ER). Plant calreticulin, in contrast to its animal counterpart, is often glycosylated: its N-glycans have been shown so far to be of the high-mannose type, typical of ER-resident glycoproteins. During the characterization of calreticulin from vegetative and reproductive tissues of Liriodendron tulipifera L., we gained some biochemical evidence that prompted us to investigate the monosaccharide composition and primary structure of the calreticulin N-glycans isolated from the ovary of this dicotyledon tree. The structures of the components of the N-glycan pool were elucidated by HPLC analysis and exoglycosidase sequencing, and further confirmed by matrix-assisted laser desorption/ionization mass spectrometry. The 16 identified oligosaccharide structures, which consisted of both the high-mannose and complex type, are indicative of calreticulin glycan processing through the ER-to-Golgi pathway up to the medial and trans Golgi stacks. Approximately 45% of calreticulin glycan chains are of the complex type, always containing beta(1,2)-xylose, and approximately a third of these also contain alpha(1,3)-fucose in the core. The most complex glycoform harbors the Lewis-a epitope Gal(beta)1-3[Fuc(alpha)1-4]GlcNAc. Immunolocalization of calreticulin with anti-calreticulin antibodies was consistent with protein transit through the Golgi. Thus, although it contains the tetrapeptide HDEL ER retention signal, the reticuloplasmin calreticulin possesses the competence to transit from the ER compartment to the distal Golgi stacks. The final fate of the protein after its complete maturation is still obscure.
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Affiliation(s)
- Lorella Navazio
- Dipartimento di Biologia, Università di Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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40
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Navazio L, Moscatiello R, Bellincampi D, Baldan B, Meggio F, Brini M, Bowler C, Mariani P. The role of calcium in oligogalacturonide-activated signalling in soybean cells. Planta 2002; 215:596-605. [PMID: 12172842 DOI: 10.1007/s00425-002-0776-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2001] [Accepted: 03/15/2002] [Indexed: 05/23/2023]
Abstract
Alpha-1,4-Linked oligogalacturonides (OGs) are pectic fragments of the plant cell wall that are perceived by the plant cell as signalling molecules. Using cytosolic aequorin-expressing soybean (Glycine max L.) cells, we have analysed cytosolic Ca(2+) changes and the oxidative burst induced by OGs with different degrees of polymerization. Our results provide evidence that different OGs are sensed through transient elevations of cytosolic Ca(2+) that show different kinetics. Specificity of the Ca(2+) signature relies also on the precise structural characteristics of the OG molecules, such as the methylesterification of galacturonic acid residues and the steric conformation. Inhibition of the OG-induced Ca(2+) transient also blocks the oxidative burst, indicating that the cytosolic Ca(2+) increase is one of the earliest steps in OG-activated signalling. However, a phosphorylation event seems to precede the Ca(2+) rise, because the Ca(2+) transient could be abolished by the protein kinase inhibitor 4,5,6,7-tetrabromobenzotriazole (TBB). A pharmacological approach with different antagonists that interfere with the induction of the cytosolic Ca(2+) rise indicates that both extracellular Ca(2+) influx and intracellular Ca(2+) release participate in transducing the OG signal. Treatment of cells with OGs establishes a refractory state, which impairs the ability of the cell to respond to a second stimulus with the same elicitor for up to 16 h. This desensitization period could be prolonged with the phosphatase inhibitor okadaic acid, and eliminated with the protein kinase inhibitor Ro 31-8220, suggesting that phosphorylation events may be involved in the establishment of the cell refractory state.
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Affiliation(s)
- Lorella Navazio
- Dipartimento di Biologia, Via U. Bassi 58/B, 35131 Padova, Italy
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41
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Baldan B, Andolfo P, Navazio L, Tolomio C, Mariani P. Cellulose in algal cell wall: an "in situ" localization. Eur J Histochem 2001; 45:51-6. [PMID: 11411865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
In order to ascertain the presence and the in muro localization of cellulose, the enzyme-gold affinity test was applied to algal cell walls. The high specificity of affinity cytochemistry allowed us, by using the enzyme cellulase, to confirm the available biochemical data and to give a map of the cellulose localization in different algal groups. Taking into account the complex skeletal polysaccharide structure and composition of the algal cell walls, this method proved to be a reliable tool in this field.
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Affiliation(s)
- B Baldan
- Dipartimento di Biologia, UNIPD, Padova.
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42
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Navazio L, Mariani P, Sanders D. Mobilization of Ca2+ by cyclic ADP-ribose from the endoplasmic reticulum of cauliflower florets. Plant Physiol 2001; 125:2129-38. [PMID: 11299392 PMCID: PMC88868 DOI: 10.1104/pp.125.4.2129] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2000] [Accepted: 01/10/2001] [Indexed: 05/18/2023]
Abstract
The NAD+ metabolite cADP-Rib (cADPR) elevates cytosolic free Ca2+ in plants and thereby plays a central role in signal transduction pathways evoked by the drought and stress hormone abscisic acid. cADPR is known to mobilize Ca2+ from the large vacuole of mature cells. To determine whether additional sites for cADPR-gated Ca2+ release reside in plant cells, microsomes from cauliflower (Brassica oleracea) inflorescences were subfractionated on sucrose density gradients, and the distribution of cADPR-elicited Ca2+ release was monitored. cADPR-gated Ca2+ release was detected in the heavy-density fractions associated with rough endoplasmic reticulum (ER). cADPR-dependent Ca2+ release co-migrated with two ER markers, calnexin and antimycin A-insensitive NADH-cytochrome c reductase activity. To investigate the possibility that contaminating plasma membrane in the ER-rich fractions was responsible for the observed release, plasma membrane vesicles were purified by aqueous two-phase partitioning, everted with Brij-58, and loaded with Ca2+: These vesicles failed to respond to cADPR. Ca2+ release evoked by cADPR at the ER was fully inhibited by ruthenium red and 8-NH2-cADPR, a specific antagonist of cADPR-gated Ca2+ release in animal cells. The presence of a Ca2+ release pathway activated by cADPR at higher plant ER reinforces the notion that, alongside the vacuole, the ER participates in Ca2+ signaling.
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Affiliation(s)
- L Navazio
- The Plant Laboratory, Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom
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Navazio L, Bewell MA, Siddiqua A, Dickinson GD, Galione A, Sanders D. Calcium release from the endoplasmic reticulum of higher plants elicited by the NADP metabolite nicotinic acid adenine dinucleotide phosphate. Proc Natl Acad Sci U S A 2000; 97:8693-8. [PMID: 10890899 PMCID: PMC27010 DOI: 10.1073/pnas.140217897] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/1999] [Accepted: 05/15/2000] [Indexed: 11/18/2022] Open
Abstract
Higher plants share with animals a responsiveness to the Ca(2+) mobilizing agents inositol 1,4,5-trisphosphate (InsP(3)) and cyclic ADP-ribose (cADPR). In this study, by using a vesicular (45)Ca(2+) flux assay, we demonstrate that microsomal vesicles from red beet and cauliflower also respond to nicotinic acid adenine dinucleotide phosphate (NAADP), a Ca(2+)-releasing molecule recently described in marine invertebrates. NAADP potently mobilizes Ca(2+) with a K(1/2) = 96 nM from microsomes of nonvacuolar origin in red beet. Analysis of sucrose gradient-separated cauliflower microsomes revealed that the NAADP-sensitive Ca(2+) pool was derived from the endoplasmic reticulum. This exclusively nonvacuolar location of the NAADP-sensitive Ca(2+) pathway distinguishes it from the InsP(3)- and cADPR-gated pathways. Desensitization experiments revealed that homogenates derived from cauliflower tissue contained low levels of NAADP (125 pmol/mg) and were competent in NAADP synthesis when provided with the substrates NADP and nicotinic acid. NAADP-induced Ca(2+) release is insensitive to heparin and 8-NH(2)-cADPR, specific inhibitors of the InsP(3)- and cADPR-controlled mechanisms, respectively. However, NAADP-induced Ca(2+) release could be blocked by pretreatment with a subthreshold dose of NAADP, as previously observed in sea urchin eggs. Furthermore, the NAADP-gated Ca(2+) release pathway is independent of cytosolic free Ca(2+) and therefore incapable of operating Ca(2+)-induced Ca(2+) release. In contrast to the sea urchin system, the NAADP-gated Ca(2+) release pathway in plants is not blocked by L-type channel antagonists. The existence of multiple Ca(2+) mobilization pathways and Ca(2+) release sites might contribute to the generation of stimulus-specific Ca(2+) signals in plant cells.
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Affiliation(s)
- L Navazio
- The Plant Laboratory, Biology Department, University of York, P.O. Box 373, York YO10 5YW, United Kingdom
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Navazio L, Nardi MC, Pancaldi S, Dainese P, Baldan B, Fitchette-Lainé AC, Faye L, Meggio F, Martin W, Mariani P. Functional conservation of calreticulin in Euglena gracilis. J Eukaryot Microbiol 1998; 45:307-13. [PMID: 9627991 DOI: 10.1111/j.1550-7408.1998.tb04541.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calreticulin is the major high capacity, low affinity Ca2+ binding protein localized within the endoplasmic reticulum. It functions as a reservoir for triggered release of Ca2+ by the endoplasmic reticulum and is thus integral to eukaryotic signal transduction pathways involving Ca2+ as a second messenger. The early branching photosynthetic protist Euglena gracilis is shown to possess calreticulin as its major high capacity Ca2+ binding protein. The protein was purified, microsequenced and cloned. Like its homologues from higher eukaryotes, calreticulin from Euglena possesses a short signal peptide for endoplasmic reticulum import and the C-terminal retention signal KDEL, indicating that these components of the eukaryotic protein routing apparatus were functional in their present form prior to divergence of the euglenozoan lineage. A gene phylogeny for calreticulin and calnexin sequences in the context of eukaryotic homologues indicates i) that these Ca2+ binding endoplasmic reticulum proteins descend from a gene duplication that occurred in the earliest stages of eukaryotic evolution and furthermore ii) that Euglenozoa express the calreticulin protein of the kinetoplastid (trypanosomes and their relatives) lineage, rather than that of the eukaryotic chlorophyte which gave rise to Euglena's plastids. Evidence for conservation of endoplasmic reticulum routing and Ca2+ binding function of calreticulin from Euglena traces the functional history of Ca2+ second messenger signal transduction pathways deep into eukaryotic evolution.
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Affiliation(s)
- L Navazio
- Dipartimento di Biologia, Università di Padova, Italy
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Navazio L, Baldan B, Mariani P, Gerwig GJ, Vliegenthart JF. Primary structure of the N-linked carbohydrate chains of Calreticulin from spinach leaves. Glycoconj J 1996; 13:977-83. [PMID: 8981089 DOI: 10.1007/bf01053193] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Calreticulin is a multifunctional Ca(2+)-binding protein of the endoplasmic reticulum of most eukaryotic cells. The 56 kDa Calreticulin glycoprotein isolated from spinach (Spinacia oleracea L.) leaves was N-deglycosylated by PNGase-F digestion. The carbohydrate moiety was isolated by gel permeation chromatography and purified by high-pH anion-exchange chromatography. The fractions were investigated by 500 MHz 1H-NMR spectroscopy, in combination with monosaccharide analysis and fast-atom bombardment-mass spectrometry. The following carbohydrate structure could be established as the major component (Man8GlcNAc2): (sequence see text) Heterogeneity was demonstrated by the presence of two minor components being Man7GlcNAc2 lacking a terminal residue (D1 or D3), compared to the major component. A cross-reactivity with an antibody against the endoplasmic reticulum retention signal HDEL was also found.
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Affiliation(s)
- L Navazio
- Department of Biology, University of Padova, Italy
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Baldan B, Navazio L, Friso A, Mariani P, Meggio F. Plant calreticulin is specifically and efficiently phosphorylated by protein kinase CK2. Biochem Biophys Res Commun 1996; 221:498-502. [PMID: 8629990 DOI: 10.1006/bbrc.1996.0625] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Calreticulin isolated from spinach leaves has been specifically phosphorylated in vitro by protein kinase CK2 while animal calreticulin from rabbit liver is not a substrate of this kinase under the same conditions. Phosphoserine is the only phosphoamino acid detected. High affinity binding (Km = 4.4 microM) and a nearly stoichiometric incorporation of phosphate was determined. Partially purified spinach calreticulin is phosphorylated at the same site(s) by a copurifying protein kinase sharing biochemical properties very similar if not identical to those of mammalian CK2. Other plant calreticulins isolated from Liriodendron tulipifera appear to be also phosphorylated by CK2.
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Affiliation(s)
- B Baldan
- Dipartimento di Biologia, Università di Padova, Italy
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Canova S, Viezzer C, Venier P, Navazio L, Revoltella R, Celotti L. Metabolic activation of benzo[a]pyrene in two fetal mouse hepatocyte lines: induction of DNA adducts and micronuclei. Mutat Res 1996; 367:135-41. [PMID: 8600369 DOI: 10.1016/0165-1218(95)00086-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have studied the metabolic competence of two non-transformed epithelial-like cell lines derived from fetal mouse liver, C 6 and C 2.8, to activate the promutagen benzo[a]pyrene by measuring both the induction of DNA adducts through the nuclease P1-enhanced 32P-postlabeling assay and the formation of micronuclei. The pattern and level of DNA adducts detected in C 6 and C 2.8 cells treated with benzo[a]pyrene were compared with those obtained in human peripheral blood lymphocytes treated with the same compound and with [3H]anti-benzo[a]pyrene diolepoxide. In both the cell lines and in human lymphocytes we observed a consistent induction of distinct DNA adducts. In C 6 and C 2.8 cells, the most evident adduct showed a position similar to that of the main adduct induced by [3H]-anti-benzo[a]pyrene diolepoxide in human lymphocytes. In addition, benzo[a]pyrene caused a significant increase of micronucleated C 6 and C 2.8 cells, whereas the frequency of micronuclei did not increase in CHO cells treated, for comparison, in the same way.
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Affiliation(s)
- S Canova
- Department of Biology, University of Padova, Italy
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Navazio L, Baldan B, Dainese P, James P, Damiani E, Margreth A, Mariani P. Evidence that spinach leaves express calreticulin but not calsequestrin. Plant Physiol 1995; 109:983-90. [PMID: 8552722 PMCID: PMC161400 DOI: 10.1104/pp.109.3.983] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The presence of either calreticulin (CR) or calsequestrin (CS-like proteins in spinach (Spinacia oleracea L.) leaves has been previously described. Here we report the purification from spinach leaves of two highly acidic (isoelectric point 5.2) Ca(2+)-binding proteins of 56 and 54 kD by means of DEAE-cellulose chromatography followed by phenyl-Sepharose chromatography in the presence of Zn(2+) (i.e., under experimental conditions that allowed the purification of CR from human liver). On the other hand, we failed to identify any protein sharing with animal CS the ability to bind to phenyl-Sepharose in the absence of Ca(2+). Based on the N-terminal amino acid sequence, the 56- and 54-kD spinach Ca(2+)-binding proteins were identified as two distinct isoforms of CR. Therefore, we conclude that CR, and not CS, is expressed in spinach leaves. The 56-kD spinach CR isoform was found to be glycosylated, as judged by ligand blot techniques with concanavalin A and affinity chromatography with concanavalin A-Sepharose. Furthermore, the 56-kD CR was found to differ from rabbit liver CR in amino acid sequence, peptide mapping after partial digestion with Staphylococcus aureus V8 protease, pH-dependent shift of electrophoretic mobility, and immunological cross-reactivity with an antiserum raised to spinach CR, indicating a low degree of structural homology with animal CRs.
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Affiliation(s)
- L Navazio
- Dipartimento di Biologia, Università di Padova, Italy
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