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Sze H, Klodová B, Ward JM, Harper JF, Palanivelu R, Johnson MA, Honys D. A wave of specific transcript and protein accumulation accompanies pollen dehydration. PLANT PHYSIOLOGY 2024; 195:1775-1795. [PMID: 38530638 DOI: 10.1093/plphys/kiae177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/13/2023] [Accepted: 01/08/2024] [Indexed: 03/28/2024]
Abstract
In flowering plants, male gametes are immotile and carried by dry pollen grains to the female organ. Dehydrated pollen is thought to withstand abiotic stress when grains are dispersed from the anther to the pistil, after which sperm cells are delivered via pollen tube growth for fertilization and seed set. Yet, the underlying molecular changes accompanying dehydration and the impact on pollen development are poorly understood. To gain a systems perspective, we analyzed published transcriptomes and proteomes of developing Arabidopsis thaliana pollen. Waves of transcripts are evident as microspores develop to bicellular, tricellular, and mature pollen. Between the "early"- and "late"-pollen-expressed genes, an unrecognized cluster of transcripts accumulated, including those encoding late-embryogenesis abundant (LEA), desiccation-related protein, transporters, lipid-droplet associated proteins, pectin modifiers, cysteine-rich proteins, and mRNA-binding proteins. Results suggest dehydration onset initiates after bicellular pollen is formed. Proteins accumulating in mature pollen like ribosomal proteins, initiation factors, and chaperones are likely components of mRNA-protein condensates resembling "stress" granules. Our analysis has revealed many new transcripts and proteins that accompany dehydration in developing pollen. Together with published functional studies, our results point to multiple processes, including (1) protect developing pollen from hyperosmotic stress, (2) remodel the endomembrane system and walls, (3) maintain energy metabolism, (4) stabilize presynthesized mRNA and proteins in condensates of dry pollen, and (5) equip pollen for compatibility determination at the stigma and for recovery at rehydration. These findings offer novel models and molecular candidates to further determine the mechanistic basis of dehydration and desiccation tolerance in plants.
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Affiliation(s)
- Heven Sze
- Department Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Božena Klodová
- Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Praha 2, 128 00, Czech Republic
| | - John M Ward
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN 55108, USA
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA
| | | | - Mark A Johnson
- Department of Molecular, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - David Honys
- Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic
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2
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Chandan K, Gupta M, Ahmad A, Sarwat M. P-type calcium ATPases play important roles in biotic and abiotic stress signaling. PLANTA 2024; 260:37. [PMID: 38922354 DOI: 10.1007/s00425-024-04462-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 06/09/2024] [Indexed: 06/27/2024]
Abstract
MAIN CONCLUSION Knowledge of Ca2+-ATPases is imperative for improving crop quality/ food security, highly threatened due to global warming. Ca2+-ATPases modulates calcium, essential for stress signaling and modulating growth, development, and immune activities. Calcium is considered a versatile secondary messenger and essential for short- and long-term responses to biotic and abiotic stresses in plants. Coordinated transport activities from both calcium influx and efflux channels are required to generate cellular calcium signals. Various extracellular stimuli cause an induction in cytosolic calcium levels. To cope with such stresses, it is important to maintain intracellular Ca2+ levels. Plants need to evolve efficient efflux mechanisms to maintain Ca2+ ion homeostasis. Plant Ca2+-ATPases are members of the P-type ATPase superfamily and localized in the plasma membrane and endoplasmic reticulum (ER). They are required for various cellular processes, including plant growth, development, calcium signaling, and even retorts to environmental stress. These ATPases play an essential role in Ca2+ homeostasis and are actively involved in Ca2+ transport. Plant Ca2+-ATPases are categorized into two major classes: type IIA and type IIB. Although these two classes of ATPases share similarities in protein sequence, they differ in their structure, cellular localization, and sensitivity to inhibitors. Due to the emerging role of Ca2+-ATPase in abiotic and biotic plant stress, members of this family may help promote agricultural improvement under stress conditions. This review provides a comprehensive overview of P-type Ca2+-ATPase, and their role in Ca2+ transport, stress signaling, and cellular homeostasis focusing on their classification, evolution, ion specificities, and catalytic mechanisms. It also describes the main aspects of the role of Ca2+-ATPase in transducing signals during plant biotic and abiotic stress responses and its role in plant development and physiology.
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Affiliation(s)
- Kumari Chandan
- Amity Institute of Pharmacy, Amity University, Noida, Uttar Pradesh, 201313, India
| | - Meenakshi Gupta
- Amity Institute of Pharmacy, Amity University, Noida, Uttar Pradesh, 201313, India
| | - Altaf Ahmad
- Department of Botany, Aligarh Muslim University, Aligarh, Uttar Pradesh, 202002, India
| | - Maryam Sarwat
- Amity Institute of Pharmacy, Amity University, Noida, Uttar Pradesh, 201313, India.
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3
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Wang Q, Cang X, Yan H, Zhang Z, Li W, He J, Zhang M, Lou L, Wang R, Chang M. Activating plant immunity: the hidden dance of intracellular Ca 2+ stores. THE NEW PHYTOLOGIST 2024; 242:2430-2439. [PMID: 38586981 DOI: 10.1111/nph.19717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/14/2024] [Indexed: 04/09/2024]
Abstract
Calcium ion (Ca2+) serves as a versatile and conserved second messenger in orchestrating immune responses. In plants, plasma membrane-localized Ca2+-permeable channels can be activated to induce Ca2+ influx from extracellular space to cytosol upon pathogen infection. Notably, different immune elicitors can induce dynamic Ca2+ signatures in the cytosol. During pattern-triggered immunity, there is a rapid and transient increase in cytosolic Ca2+, whereas in effector-triggered immunity, the elevation of cytosolic Ca2+ is strong and sustained. Numerous Ca2+ sensors are localized in the cytosol or different intracellular organelles, which are responsible for detecting and converting Ca2+ signals. In fact, Ca2+ signaling coordinated by cytosol and subcellular compartments plays a crucial role in activating plant immune responses. However, the complete Ca2+ signaling network in plant cells is still largely ambiguous. This review offers a comprehensive insight into the collaborative role of intracellular Ca2+ stores in shaping the Ca2+ signaling network during plant immunity, and several intriguing questions for future research are highlighted.
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Affiliation(s)
- Qi Wang
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaoyan Cang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Haiqiao Yan
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zilu Zhang
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Wei Li
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jinyu He
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Meixiang Zhang
- College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China
| | - Laiqing Lou
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ran Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450046, China
| | - Ming Chang
- Key Laboratory of Soybean Disease and Pest Control (Ministry of Agriculture and Rural Affairs), Key Laboratory of Plant Immunity, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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Davis JA, Poulsen LR, Kjeldgaard B, Moog MW, Brown E, Palmgren M, López-Marqués RL, Harper JF. Deficiencies in cluster-2 ALA lipid flippases result in salicylic acid-dependent growth reductions. PHYSIOLOGIA PLANTARUM 2024; 176:e14228. [PMID: 38413387 DOI: 10.1111/ppl.14228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/08/2024] [Accepted: 02/12/2024] [Indexed: 02/29/2024]
Abstract
P4 ATPases (i.e., lipid flippases) are eukaryotic enzymes that transport lipids across membrane bilayers. In plants, P4 ATPases are named Aminophospholipid ATPases (ALAs) and are organized into five phylogenetic clusters. Here we generated an Arabidopsis mutant lacking all five cluster-2 ALAs (ala8/9/10/11/12), which is the most highly expressed ALA subgroup in vegetative tissues. Plants harboring the quintuple knockout (KO) show rosettes that are 2.2-fold smaller and display chlorotic lesions. A similar but less severe phenotype was observed in an ala10/11 double KO. The growth and lesion phenotypes of ala8/9/10/11/12 mutants were reversed by expressing a NahG transgene, which encodes an enzyme that degrades salicylic acid (SA). A role for SA in promoting the lesion phenotype was further supported by quantitative PCR assays showing increased mRNA abundance for an SA-biosynthesis gene ISOCHORISMATE SYNTHASE 1 (ICS1) and two SA-responsive genes PATHOGENESIS-RELATED GENE 1 (PR1) and PR2. Lesion phenotypes were also reversed by growing plants in liquid media containing either low calcium (~0.1 mM) or high nitrogen concentrations (~24 mM), which are conditions known to suppress SA-dependent autoimmunity. Yeast-based fluorescent lipid uptake assays revealed that ALA10 and ALA11 display overlapping substrate specificities, including the transport of LysoPC signaling lipids. Together, these results establish that the biochemical functions of ALA8-12 are at least partially overlapping, and that deficiencies in cluster-2 ALAs result in an SA-dependent autoimmunity phenotype that has not been observed for flippase mutants with deficiencies in other ALA clusters.
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Affiliation(s)
- James A Davis
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Lisbeth R Poulsen
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Bodil Kjeldgaard
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Max W Moog
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Elizabeth Brown
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Rosa L López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
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5
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Wang C, Tang RJ, Kou S, Xu X, Lu Y, Rauscher K, Voelker A, Luan S. Mechanisms of calcium homeostasis orchestrate plant growth and immunity. Nature 2024; 627:382-388. [PMID: 38418878 DOI: 10.1038/s41586-024-07100-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 01/22/2024] [Indexed: 03/02/2024]
Abstract
Calcium (Ca2+) is an essential nutrient for plants and a cellular signal, but excessive levels can be toxic and inhibit growth1,2. To thrive in dynamic environments, plants must monitor and maintain cytosolic Ca2+ homeostasis by regulating numerous Ca2+ transporters3. Here we report two signalling pathways in Arabidopsis thaliana that converge on the activation of vacuolar Ca2+/H+ exchangers (CAXs) to scavenge excess cytosolic Ca2+ in plants. One mechanism, activated in response to an elevated external Ca2+ level, entails calcineurin B-like (CBL) Ca2+ sensors and CBL-interacting protein kinases (CIPKs), which activate CAXs by phosphorylating a serine (S) cluster in the auto-inhibitory domain. The second pathway, triggered by molecular patterns associated with microorganisms, engages the immune receptor complex FLS2-BAK1 and the associated cytoplasmic kinases BIK1 and PBL1, which phosphorylate the same S-cluster in CAXs to modulate Ca2+ signals in immunity. These Ca2+-dependent (CBL-CIPK) and Ca2+-independent (FLS2-BAK1-BIK1/PBL1) mechanisms combine to balance plant growth and immunity by regulating cytosolic Ca2+ homeostasis.
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Affiliation(s)
- Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Ren-Jie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Senhao Kou
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Xiaoshu Xu
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Yi Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Kenda Rauscher
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Angela Voelker
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA.
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6
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Wang X, Wang Z, Lu Y, Huang J, Hu Z, Lou J, Fan X, Gu Z, Liu P, Ma B, Chen X. OsACA9, an Autoinhibited Ca 2+-ATPase, Synergically Regulates Disease Resistance and Leaf Senescence in Rice. Int J Mol Sci 2024; 25:1874. [PMID: 38339152 PMCID: PMC10856199 DOI: 10.3390/ijms25031874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/27/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Calcium (Ca2+) is a versatile intracellular second messenger that regulates several signaling pathways involved in growth, development, stress tolerance, and immune response in plants. Autoinhibited Ca2+-ATPases (ACAs) play an important role in the regulation of cellular Ca2+ homeostasis. Here, we systematically analyzed the putative OsACA family members in rice, and according to the phylogenetic tree of OsACAs, OsACA9 was clustered into a separated branch in which its homologous gene in Arabidopsis thaliana was reported to be involved in defense response. When the OsACA9 gene was knocked out by CRISPR/Cas9, significant accumulation of reactive oxygen species (ROS) was detected in the mutant lines. Meanwhile, the OsACA9 knock out lines showed enhanced disease resistance to both rice bacterial blight (BB) and bacterial leaf streak (BLS). In addition, compared to the wild-type (WT), the mutant lines displayed an early leaf senescence phenotype, and the agronomy traits of their plant height, panicle length, and grain yield were significantly decreased. Transcriptome analysis by RNA-Seq showed that the differentially expressed genes (DEGs) between WT and the Osaca9 mutant were mainly enriched in basal immune pathways and antibacterial metabolite synthesis pathways. Among them, multiple genes related to rice disease resistance, receptor-like cytoplasmic kinases (RLCKs) and cell wall-associated kinases (WAKs) genes were upregulated. Our results suggest that the Ca2+-ATPase OsACA9 may trigger oxidative burst in response to various pathogens and synergically regulate disease resistance and leaf senescence in rice.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Xifeng Chen
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (X.W.); (Y.L.); (Z.H.); (J.L.); (Z.G.); (P.L.)
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7
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Wang C, Luan S. Calcium homeostasis and signaling in plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2024; 77:102485. [PMID: 38043138 DOI: 10.1016/j.pbi.2023.102485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 12/05/2023]
Abstract
Calcium (Ca2+) signaling consists of three steps: (1) initiation of a change in cellular Ca2+ concentration in response to a stimulus, (2) recognition of the change through direct binding of Ca2+ by its sensors, (3) transduction of the signal to elicit downstream responses. Recent studies have uncovered a central role for Ca2+ signaling in both layers of immune responses initiated by plasma membrane (PM) and intracellular receptors, respectively. These advances in our understanding are attributed to several lines of research, including invention of genetically-encoded Ca2+ reporters for the recording of intracellular Ca2+ signals, identification of Ca2+ channels and their gating mechanisms, and functional analysis of Ca2+ binding proteins (Ca2+ sensors). This review analyzes the recent literature that illustrates the importance of Ca2+ homeostasis and signaling in plant innate immunity, featuring intricate Ca2+dependent positive and negative regulations.
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Affiliation(s)
- Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
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8
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Stéger A, Palmgren M. Hypothesis paper: the development of a regulatory layer in P2B autoinhibited Ca 2+-ATPases may have facilitated plant terrestrialization and animal multicellularization. PLANT SIGNALING & BEHAVIOR 2023; 18:2204284. [PMID: 37096591 PMCID: PMC10132250 DOI: 10.1080/15592324.2023.2204284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
With the appearance of plants and animals, new challenges emerged. These multicellular eukaryotes had to solve for example the difficulties of multifaceted communication between cells and adaptation to new habitats. In this paper, we are looking for one piece of the puzzle that made the development of complex multicellular eukaryotes possible with a focus on regulation of P2B autoinhibited Ca2+-ATPases. P2B ATPases pump Ca2+ out of the cytosol at the expense of ATP hydrolysis, and thereby maintain a steep gradient between the extra- and intracytosolic compartments which is utilized for Ca2+-mediated rapid cell signaling. The activity of these enzymes is regulated by a calmodulin (CaM)-responsive autoinhibitory region, which can be located in either termini of the protein, at the C-terminus in animals and at the N-terminus in plants. When the cytoplasmic Ca2+ level reaches a threshold, the CaM/Ca2+ complex binds to a calmodulin-binding domain (CaMBD) in the autoinhibitor, which leads to the upregulation of pump activity. In animals, protein activity is also controlled by acidic phospholipids that bind to a cytosolic portion of the pump. Here, we analyze the appearance of CaMBDs and the phospholipid-activating sequence and show that their evolution in animals and plants was independent. Furthermore, we hypothesize that different causes may have initiated the appearance of these regulatory layers: in animals, it is linked to the appearance of multicellularity, while in plants it co-occurs with their water-to-land transition.
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Affiliation(s)
- Anett Stéger
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- CONTACT Michael Palmgren Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, FrederiksbergDK-1871, Denmark
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9
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Bakshi A, Choi WG, Kim SH, Gilroy S. The vacuolar Ca 2+ transporter CATION EXCHANGER 2 regulates cytosolic calcium homeostasis, hypoxic signaling, and response to flooding in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2023; 240:1830-1847. [PMID: 37743731 DOI: 10.1111/nph.19274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Abstract
Flooding represents a major threat to global agricultural productivity and food security, but plants are capable of deploying a suite of adaptive responses that can lead to short- or longer-term survival to this stress. One cellular pathway thought to help coordinate these responses is via flooding-triggered Ca2+ signaling. We have mined publicly available transcriptomic data from Arabidopsis subjected to flooding or low oxygen stress to identify rapidly upregulated, Ca2+ -related transcripts. We then focused on transporters likely to modulate Ca2+ signals. Candidates emerging from this analysis included AUTOINHIBITED Ca2+ ATPASE 1 and CATION EXCHANGER 2. We therefore assayed mutants in these genes for flooding sensitivity at levels from growth to patterns of gene expression and the kinetics of flooding-related Ca2+ changes. Knockout mutants in CAX2 especially showed enhanced survival to soil waterlogging coupled with suppressed induction of many marker genes for hypoxic response and constitutive activation of others. CAX2 mutants also generated larger and more sustained Ca2+ signals in response to both flooding and hypoxic challenges. CAX2 is a Ca2+ transporter located on the tonoplast, and so these results are consistent with an important role for vacuolar Ca2+ transport in the signaling systems that trigger flooding response.
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Affiliation(s)
- Arkadipta Bakshi
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia St, Reno, NV, 89557, USA
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia St, Reno, NV, 89557, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
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10
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Nguyen TBA, Lefoulon C, Nguyen TH, Blatt MR, Carroll W. Engineering stomata for enhanced carbon capture and water-use efficiency. TRENDS IN PLANT SCIENCE 2023; 28:1290-1309. [PMID: 37423785 DOI: 10.1016/j.tplants.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/29/2023] [Accepted: 06/02/2023] [Indexed: 07/11/2023]
Abstract
Stomatal pores facilitate gaseous exchange between the inner air spaces of the leaf and the atmosphere. As gatekeepers that balance CO2 entry for photosynthesis against transpirational water loss, they are a focal point for efforts to improve crop performance, especially in the efficiency of water use, within the changing global environment. Until recently, engineering strategies had focused on stomatal conductance in the steady state. These strategies are limited by the physical constraints of CO2 and water exchange such that gains in water-use efficiency (WUE) commonly come at a cost in carbon assimilation. Attention to stomatal speed and responsiveness circumvents these constraints and offers alternatives to enhancing WUE that also promise increases in carbon assimilation in the field.
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Affiliation(s)
- Thu Binh-Anh Nguyen
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Cecile Lefoulon
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Thanh-Hao Nguyen
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - William Carroll
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
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11
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Costa A, Resentini F, Buratti S, Bonza MC. Plant Ca 2+-ATPases: From biochemistry to signalling. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119508. [PMID: 37290725 DOI: 10.1016/j.bbamcr.2023.119508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 06/10/2023]
Abstract
Calcium (Ca2+)-ATPases are ATP-dependent enzymes that transport Ca2+ ions against their electrochemical gradient playing the fundamental biological function of keeping the free cytosolic Ca2+ concentration in the submicromolar range to prevent cytotoxic effects. In plants, type IIB autoinhibited Ca2+-ATPases (ACAs) are localised both at the plasma membrane and at the endomembranes including endoplasmic reticulum (ER) and tonoplast and their activity is primarily regulated by Ca2+-dependent mechanisms. Instead, type IIA ER-type Ca2+-ATPases (ECAs) are present mainly at the ER and Golgi Apparatus membranes and are active at resting Ca2+. Whereas research in plants has historically focused on the biochemical characterization of these pumps, more recently the attention has been also addressed on the physiological roles played by the different isoforms. This review aims to highlight the main biochemical properties of both type IIB and type IIA Ca2+ pumps and their involvement in the shaping of cellular Ca2+ dynamics induced by different stimuli.
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Affiliation(s)
- Alex Costa
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy; Institute of Biophysics, National Research Council of Italy (CNR), 20133 Milano, Italy.
| | - Francesca Resentini
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy
| | - Stefano Buratti
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy.
| | - Maria Cristina Bonza
- Department of Biosciences, University of Milan, via Celoria 26, 20133 Milano, Italy.
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12
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Li Z, Harper JF, Weigand C, Hua J. Resting cytosol Ca2+ level maintained by Ca2+ pumps affects environmental responses in Arabidopsis. PLANT PHYSIOLOGY 2023; 191:2534-2550. [PMID: 36715402 PMCID: PMC10069881 DOI: 10.1093/plphys/kiad047] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 12/26/2022] [Indexed: 06/10/2023]
Abstract
Calcium ion transporting systems control cytosol Ca2+ levels ([Ca2+]cyt) and generate transient calcium (Ca2+) signatures that are key to environmental responses. Here, we report an impact of resting [Ca2+]cyt on plants from the functional study of calmodulin-regulated Ca2+ pumps or Ca2+-ATPases in Arabidopsis (Arabidopsis thaliana). The plasma membrane-localized pumps ACA8 (autoinhibited Ca2+-ATPase) and ACA10, as well as the vacuole-localized pumps ACA4 and ACA11, were critical in maintaining low resting [Ca2+]cyt and essential for plant survival under chilling and heat-stress conditions. Their loss-of-function mutants aca8 aca10 and aca4 aca11 had autoimmunity at normal temperatures, and this deregulated immune activation was enhanced by low temperature, leading to chilling lethality. Furthermore, these mutants showed an elevated resting [Ca2+]cyt, and a reduction of external Ca2+ lowered [Ca2+]cyt and repressed their autoimmunity and cold susceptibility. The aca8 aca10 and the aca4 aca11 mutants were also susceptible to heat, likely resulting from more closed stomata and higher leaf surface temperature than the wild type. These observations support a model in which the regulation of resting [Ca2+]cyt is critical to how plants regulate biotic and abiotic responses.
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Affiliation(s)
- Zhan Li
- School of Integrative Plant Science, Plant Biology Section, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA
| | - Chrystle Weigand
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA
| | - Jian Hua
- School of Integrative Plant Science, Plant Biology Section, Cornell University, Ithaca, NY 14853, USA
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13
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Wang J, Song W, Chai J. Structure, biochemical function, and signaling mechanism of plant NLRs. MOLECULAR PLANT 2023; 16:75-95. [PMID: 36415130 DOI: 10.1016/j.molp.2022.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/07/2022] [Accepted: 11/21/2022] [Indexed: 06/16/2023]
Abstract
To counter pathogen invasion, plants have evolved a large number of immune receptors, including membrane-resident pattern recognition receptors (PRRs) and intracellular nucleotide-binding and leucine-rich repeat receptors (NLRs). Our knowledge about PRR and NLR signaling mechanisms has expanded significantly over the past few years. Plant NLRs form multi-protein complexes called resistosomes in response to pathogen effectors, and the signaling mediated by NLR resistosomes converges on Ca2+-permeable channels. Ca2+-permeable channels important for PRR signaling have also been identified. These findings highlight a crucial role of Ca2+ in triggering plant immune signaling. In this review, we first discuss the structural and biochemical mechanisms of non-canonical NLR Ca2+ channels and then summarize our knowledge about immune-related Ca2+-permeable channels and their roles in PRR and NLR signaling. We also discuss the potential role of Ca2+ in the intricate interaction between PRR and NLR signaling.
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Affiliation(s)
- Jizong Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences, Peking University, Beijing 100871, China; Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, Shandong 261000, China.
| | - Wen Song
- Institute of Biochemistry, University of Cologne, 50674 Cologne, Germany; Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
| | - Jijie Chai
- Tsinghua-Peking Joint Center for Life Sciences, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Institute of Biochemistry, University of Cologne, 50674 Cologne, Germany; Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
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14
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Li J, Ma M, Sun Y, Lu P, Shi H, Guo Z, Zhu H. Comparative Physiological and Transcriptome Profiles Uncover Salt Tolerance Mechanisms in Alfalfa. FRONTIERS IN PLANT SCIENCE 2022; 13:931619. [PMID: 35755671 PMCID: PMC9218637 DOI: 10.3389/fpls.2022.931619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Salinity is a major limiting factor that affects crop production. Understanding of the mechanisms of plant salt tolerance is critical for improving crop yield on saline land. Alfalfa (Medicago sativa L.) is the most important forage crop, while its salt tolerance mechanisms are largely unknown. The physiological and transcriptomic responses in two contrasting salt tolerant cultivars to salinity stress were investigated in the present study. "Magnum Salt" showed higher salt tolerance than "Adrenalin," with higher relative germination rate, survival rate, biomass and K+/Na+ ratio after salt treatment. Activities of antioxidant enzymes SOD, CAT and GR, and proline concentrations were upregulated to higher levels in roots and shoots in Magnum Salt than in Adrenalin after salinity stress, except for no difference in GR activity in shoots, and lower levels of O2 ⋅- and H2O2 were accumulated in leaves. It was interesting to find that salinity caused a decrease in total unsaturated fatty acid in Adrenalin other than Magnum Salt, C18:2 was increased significantly after salinity in Magnum Salt, while it was unaltered in Adrenalin. High quality RNA sequencing (RNA-seq) data was obtained from samples of Magnum Salt and Adrenalin at different time points (0, 2, and 26 h). Generally, "phagosome," "TCA cycle" and "oxidative phosphorylation" pathways were inhibited by salinity stress. Upregulated DEGs in Magnum Salt were specifically enriched in "fatty acid metabolism," "MAPK signaling" and "hormone signal transduction" pathways. The DEGs involved in ionic homeostasis, reactive oxygen species (ROS) scavenging and fatty acid metabolism could partially explain the difference in salt tolerance between two cultivars. It is suggested that salt tolerance in alfalfa is associated with regulation of ionic homeostasis, antioxidative enzymes and fatty acid metabolism at both transcriptional and physiological level.
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15
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ACA pumps maintain leaf excitability during herbivore onslaught. Curr Biol 2022; 32:2517-2528.e6. [PMID: 35413240 DOI: 10.1016/j.cub.2022.03.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 02/09/2022] [Accepted: 03/21/2022] [Indexed: 01/07/2023]
Abstract
Recurrent damage by lepidopteran folivores triggers repeated leaf-to-leaf electrical signaling. We found that the ability to propagate electrical signals-called slow wave potentials-was unexpectedly robust and was maintained in plants that had experienced severe damage. We sought genes that maintain tissue excitability during group insect attack. When Arabidopsis thaliana P-Type II Ca2+-ATPase mutants were mechanically wounded, all mutants tested displayed leaf-to-leaf electrical signals. However, when the auto-inhibited Ca2+-ATPase double-mutant aca10 aca12 was attacked by Spodoptera littoralis caterpillars, electrical signaling failed catastrophically, and the insects consumed these plants rapidly. The attacked double mutant displayed petiole base deformation and chlorosis, which spread acropetally into laminas and led to senescence. A phloem-feeding aphid recapitulated these effects, implicating the vasculature in electrical signaling failure. Consistent with this, ACA10 expressed in phloem companion cells in an aca10 aca12 background rescued electrical signaling and defense during protracted S. littoralis attack. When expressed in xylem contact cells, ACA10 partially rescued these phenotypes. Extending our analyses, we found that prolonged darkness also caused wound-response electrical signaling failure in aca10 aca12 mutants. Our results lead to a model in which the plant vasculature acts as a capacitor that discharges temporarily when leaves are subjected to energy-depleting stresses. Under these conditions, ACA10 and ACA12 function allows the restoration of vein cell membrane potentials. In the absence of these gene functions, vascular cell excitability can no longer be restored efficiently. Additionally, this work demonstrates that non-invasive electrophysiology is a powerful tool for probing early events underlying senescence.
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16
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Resentini F, Ruberti C, Grenzi M, Bonza MC, Costa A. The signatures of organellar calcium. PLANT PHYSIOLOGY 2021; 187:1985-2004. [PMID: 33905517 PMCID: PMC8644629 DOI: 10.1093/plphys/kiab189] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/10/2021] [Indexed: 05/23/2023]
Abstract
Recent insights about the transport mechanisms involved in the in and out of calcium ions in plant organelles, and their role in the regulation of cytosolic calcium homeostasis in different signaling pathways.
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Affiliation(s)
| | - Cristina Ruberti
- Department of Biosciences, University of Milan, Milano 20133, Italy
| | - Matteo Grenzi
- Department of Biosciences, University of Milan, Milano 20133, Italy
| | | | - Alex Costa
- Department of Biosciences, University of Milan, Milano 20133, Italy
- Institute of Biophysics, National Research Council of Italy (CNR), Milano 20133, Italy
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17
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He J, Rössner N, Hoang MTT, Alejandro S, Peiter E. Transport, functions, and interaction of calcium and manganese in plant organellar compartments. PLANT PHYSIOLOGY 2021; 187:1940-1972. [PMID: 35235665 PMCID: PMC8890496 DOI: 10.1093/plphys/kiab122] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/02/2021] [Indexed: 05/05/2023]
Abstract
Calcium (Ca2+) and manganese (Mn2+) are essential elements for plants and have similar ionic radii and binding coordination. They are assigned specific functions within organelles, but share many transport mechanisms to cross organellar membranes. Despite their points of interaction, those elements are usually investigated and reviewed separately. This review takes them out of this isolation. It highlights our current mechanistic understanding and points to open questions of their functions, their transport, and their interplay in the endoplasmic reticulum (ER), vesicular compartments (Golgi apparatus, trans-Golgi network, pre-vacuolar compartment), vacuoles, chloroplasts, mitochondria, and peroxisomes. Complex processes demanding these cations, such as Mn2+-dependent glycosylation or systemic Ca2+ signaling, are covered in some detail if they have not been reviewed recently or if recent findings add to current models. The function of Ca2+ as signaling agent released from organelles into the cytosol and within the organelles themselves is a recurrent theme of this review, again keeping the interference by Mn2+ in mind. The involvement of organellar channels [e.g. glutamate receptor-likes (GLR), cyclic nucleotide-gated channels (CNGC), mitochondrial conductivity units (MCU), and two-pore channel1 (TPC1)], transporters (e.g. natural resistance-associated macrophage proteins (NRAMP), Ca2+ exchangers (CAX), metal tolerance proteins (MTP), and bivalent cation transporters (BICAT)], and pumps [autoinhibited Ca2+-ATPases (ACA) and ER Ca2+-ATPases (ECA)] in the import and export of organellar Ca2+ and Mn2+ is scrutinized, whereby current controversial issues are pointed out. Mechanisms in animals and yeast are taken into account where they may provide a blueprint for processes in plants, in particular, with respect to tunable molecular mechanisms of Ca2+ versus Mn2+ selectivity.
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Affiliation(s)
- Jie He
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nico Rössner
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Minh T T Hoang
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Santiago Alejandro
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Edgar Peiter
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
- Author for communication:
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18
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Fuglsang AT, Palmgren M. Proton and calcium pumping P-type ATPases and their regulation of plant responses to the environment. PLANT PHYSIOLOGY 2021; 187:1856-1875. [PMID: 35235671 PMCID: PMC8644242 DOI: 10.1093/plphys/kiab330] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/23/2021] [Indexed: 05/10/2023]
Abstract
Plant plasma membrane H+-ATPases and Ca2+-ATPases maintain low cytoplasmic concentrations of H+ and Ca2+, respectively, and are essential for plant growth and development. These low concentrations allow plasma membrane H+-ATPases to function as electrogenic voltage stats, and Ca2+-ATPases as "off" mechanisms in Ca2+-based signal transduction. Although these pumps are autoregulated by cytoplasmic concentrations of H+ and Ca2+, respectively, they are also subject to exquisite regulation in response to biotic and abiotic events in the environment. A common paradigm for both types of pumps is the presence of terminal regulatory (R) domains that function as autoinhibitors that can be neutralized by multiple means, including phosphorylation. A picture is emerging in which some of the phosphosites in these R domains appear to be highly, nearly constantly phosphorylated, whereas others seem to be subject to dynamic phosphorylation. Thus, some sites might function as major switches, whereas others might simply reduce activity. Here, we provide an overview of the relevant transport systems and discuss recent advances that address their relation to external stimuli and physiological adaptations.
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Affiliation(s)
- Anja T Fuglsang
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
- Author for communication:
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19
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Resentini F, Grenzi M, Ancora D, Cademartori M, Luoni L, Franco M, Bassi A, Bonza MC, Costa A. Simultaneous imaging of ER and cytosolic Ca2+ dynamics reveals long-distance ER Ca2+ waves in plants. PLANT PHYSIOLOGY 2021; 187:603-617. [PMID: 34608947 PMCID: PMC8491065 DOI: 10.1093/plphys/kiab251] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/12/2021] [Indexed: 05/07/2023]
Abstract
Calcium ions (Ca2+) play a key role in cell signaling across organisms. In plants, a plethora of environmental and developmental stimuli induce specific Ca2+ increases in the cytosol as well as in different cellular compartments including the endoplasmic reticulum (ER). The ER represents an intracellular Ca2+ store that actively accumulates Ca2+ taken up from the cytosol. By exploiting state-of-the-art genetically encoded Ca2+ indicators, specifically the ER-GCaMP6-210 and R-GECO1, we report the generation and characterization of an Arabidopsis (Arabidopsis thaliana) line that allows for simultaneous imaging of Ca2+ dynamics in both the ER and cytosol at different spatial scales. By performing analyses in single cells, we precisely quantified (1) the time required by the ER to import Ca2+ from the cytosol into the lumen and (2) the time required to observe a cytosolic Ca2+ increase upon the pharmacological inhibition of the ER-localized P-Type IIA Ca2+-ATPases. Furthermore, live imaging of mature, soil-grown plants revealed the existence of a wounding-induced, long-distance ER Ca2+ wave propagating in injured and systemic rosette leaves. This technology enhances high-resolution analyses of intracellular Ca2+ dynamics at the cellular level and in adult organisms and paves the way to develop new methodologies aimed at defining the contribution of subcellular compartments in Ca2+ homeostasis and signaling.
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Affiliation(s)
| | - Matteo Grenzi
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Daniele Ancora
- Department of Physics, Politecnico di Milano, Milan 20133, Italy
| | - Mara Cademartori
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Laura Luoni
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Marianna Franco
- Department of Biosciences, University of Milan, Milan 20133, Italy
| | - Andrea Bassi
- Department of Physics, Politecnico di Milano, Milan 20133, Italy
| | | | - Alex Costa
- Department of Biosciences, University of Milan, Milan 20133, Italy
- Institute of Biophysics, Consiglio Nazionale Delle Ricerche, Milan 20133, Italy
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20
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Grenzi M, Resentini F, Vanneste S, Zottini M, Bassi A, Costa A. Illuminating the hidden world of calcium ions in plants with a universe of indicators. PLANT PHYSIOLOGY 2021; 187:550-571. [PMID: 35237821 PMCID: PMC8491032 DOI: 10.1093/plphys/kiab339] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/15/2021] [Indexed: 05/20/2023]
Abstract
The tools available to carry out in vivo analysis of Ca2+ dynamics in plants are powerful and mature technologies that still require the proper controls.
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Affiliation(s)
- Matteo Grenzi
- Department of Biosciences, University of Milan, 20133 Milano, Italy
| | | | - Steffen Vanneste
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Department of Plants and Crops, Ghent University, 9000 Ghent, Belgium
- Laboratory of Plant Growth Analysis, Ghent University Global Campus, Incheon 21985, South Korea
| | - Michela Zottini
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Andrea Bassi
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy
- Institute of Photonics and Nanotechnologies, National Research Council of Italy (CNR), 20133 Milano, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milano, Italy
- Institute of Biophysics, National Research Council of Italy (CNR), 20133 Milano, Italy
- Author for communication:
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21
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Jezek M, Silva-Alvim FAL, Hills A, Donald N, Ishka MR, Shadbolt J, He B, Lawson T, Harper JF, Wang Y, Lew VL, Blatt MR. Guard cell endomembrane Ca 2+-ATPases underpin a 'carbon memory' of photosynthetic assimilation that impacts on water-use efficiency. NATURE PLANTS 2021; 7:1301-1313. [PMID: 34326530 DOI: 10.1038/s41477-021-00966-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
Stomata of most plants close to preserve water when the demand for CO2 by photosynthesis is reduced. Stomatal responses are slow compared with photosynthesis, and this kinetic difference erodes assimilation and water-use efficiency under fluctuating light. Despite a deep knowledge of guard cells that regulate the stoma, efforts to enhance stomatal kinetics are limited by our understanding of its control by foliar CO2. Guided by mechanistic modelling that incorporates foliar CO2 diffusion and mesophyll photosynthesis, here we uncover a central role for endomembrane Ca2+ stores in guard cell responsiveness to fluctuating light and CO2. Modelling predicted and experiments demonstrated a delay in Ca2+ cycling that was enhanced by endomembrane Ca2+-ATPase mutants, altering stomatal conductance and reducing assimilation and water-use efficiency. Our findings illustrate the power of modelling to bridge the gap from the guard cell to whole-plant photosynthesis, and they demonstrate an unforeseen latency, or 'carbon memory', of guard cells that affects stomatal dynamics, photosynthesis and water-use efficiency.
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Affiliation(s)
- Mareike Jezek
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | | | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Naomi Donald
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Maryam Rahmati Ishka
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Jessica Shadbolt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK
| | - Bingqing He
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Yizhou Wang
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Virgilio L Lew
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow, UK.
- Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
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22
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A Molecular Pinball Machine of the Plasma Membrane Regulates Plant Growth-A New Paradigm. Cells 2021; 10:cells10081935. [PMID: 34440704 PMCID: PMC8391756 DOI: 10.3390/cells10081935] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/23/2021] [Accepted: 07/25/2021] [Indexed: 12/31/2022] Open
Abstract
Novel molecular pinball machines of the plasma membrane control cytosolic Ca2+ levels that regulate plant metabolism. The essential components involve: 1. an auxin-activated proton pump; 2. arabinogalactan glycoproteins (AGPs); 3. Ca2+ channels; 4. auxin-efflux "PIN" proteins. Typical pinball machines release pinballs that trigger various sound and visual effects. However, in plants, "proton pinballs" eject Ca2+ bound by paired glucuronic acid residues of numerous glycomodules in periplasmic AGP-Ca2+. Freed Ca2+ ions flow down the electrostatic gradient through open Ca2+ channels into the cytosol, thus activating numerous Ca2+-dependent activities. Clearly, cytosolic Ca2+ levels depend on the activity of the proton pump, the state of Ca2+ channels and the size of the periplasmic AGP-Ca2+ capacitor; proton pump activation is a major regulatory focal point tightly controlled by the supply of auxin. Auxin efflux carriers conveniently known as "PIN" proteins (null mutants are pin-shaped) pump auxin from cell to cell. Mechanosensitive Ca2+ channels and their activation by reactive oxygen species (ROS) are yet another factor regulating cytosolic Ca2+. Cell expansion also triggers proton pump/pinball activity by the mechanotransduction of wall stress via Hechtian adhesion, thus forming a Hechtian oscillator that underlies cycles of wall plasticity and oscillatory growth. Finally, the Ca2+ homeostasis of plants depends on cell surface external storage as a source of dynamic Ca2+, unlike the internal ER storage source of animals, where the added regulatory complexities ranging from vitamin D to parathormone contrast with the elegant simplicity of plant life. This paper summarizes a sixty-year Odyssey.
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23
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Weigand C, Kim SH, Brown E, Medina E, Mares M, Miller G, Harper JF, Choi WG. A Ratiometric Calcium Reporter CGf Reveals Calcium Dynamics Both in the Single Cell and Whole Plant Levels Under Heat Stress. FRONTIERS IN PLANT SCIENCE 2021; 12:777975. [PMID: 34975960 PMCID: PMC8718611 DOI: 10.3389/fpls.2021.777975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/17/2021] [Indexed: 05/02/2023]
Abstract
Land plants evolved to quickly sense and adapt to temperature changes, such as hot days and cold nights. Given that calcium (Ca2+) signaling networks are implicated in most abiotic stress responses, heat-triggered changes in cytosolic Ca2+ were investigated in Arabidopsis leaves and pollen. Plants were engineered with a reporter called CGf, a ratiometric, genetically encoded Ca2+ reporter with an mCherry reference domain fused to an intensiometric Ca2+ reporter GCaMP6f. Relative changes in [Ca2+]cyt were estimated based on CGf's apparent K D around 220 nM. The ratiometric output provided an opportunity to compare Ca2+ dynamics between different tissues, cell types, or subcellular locations. In leaves, CGf detected heat-triggered cytosolic Ca2+ signals, comprised of three different signatures showing similarly rapid rates of Ca2+ influx followed by differing rates of efflux (50% durations ranging from 5 to 19 min). These heat-triggered Ca2+ signals were approximately 1.5-fold greater in magnitude than blue light-triggered signals in the same leaves. In contrast, growing pollen tubes showed two different heat-triggered responses. Exposure to heat caused tip-focused steady growth [Ca2+]cyt oscillations to shift to a pattern characteristic of a growth arrest (22%), or an almost undetectable [Ca2+]cyt (78%). Together, these contrasting examples of heat-triggered Ca2+ responses in leaves and pollen highlight the diversity of Ca2+ signals in plants, inviting speculations about their differing kinetic features and biological functions.
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Affiliation(s)
- Chrystle Weigand
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Elizabeth Brown
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Emily Medina
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Moises Mares
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Jeffrey F. Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- *Correspondence: Jeffrey F. Harper,
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- Won-Gyu Choi,
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