1
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Gwon S, Park J, Huque AM, Cheung LS. The Arabidopsis SWEET1 and SWEET2 uniporters recognize similar substrates while differing in subcellular localization. J Biol Chem 2023; 299:105389. [PMID: 37890779 PMCID: PMC10694572 DOI: 10.1016/j.jbc.2023.105389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Sugars Will Eventually be Exported Transporters (SWEETs) are central for sugar allocation in plants. The SWEET family has approximately 20 homologs in most plant genomes, and despite extensive research on their structures and molecular functions, it is still unclear how diverse SWEETs recognize different substrates. Previous work using SweetTrac1, a biosensor constructed by the intramolecular fusion of a conformation-sensitive fluorescent protein in the plasma membrane transporter SWEET1 from Arabidopsis thaliana, identified common features in the transporter's substrates. Here, we report SweetTrac2, a new biosensor based on the Arabidopsis vacuole membrane transporter SWEET2, and use it to explore the substrate specificity of this second protein. Our results show that SWEET1 and SWEET2 recognize similar substrates but some with different affinities. Sequence comparison and mutagenesis analysis support the conclusion that the differences in affinity depend on nonspecific interactions involving previously uncharacterized residues in the substrate-binding pocket. Furthermore, SweetTrac2 can be an effective tool for monitoring sugar transport at vacuolar membranes that would be otherwise challenging to study.
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Affiliation(s)
- Sojeong Gwon
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Jihyun Park
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Akm Mahmudul Huque
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Lily S Cheung
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
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2
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Sadoine M, De Michele R, Župunski M, Grossmann G, Castro-Rodríguez V. Monitoring nutrients in plants with genetically encoded sensors: achievements and perspectives. PLANT PHYSIOLOGY 2023; 193:195-216. [PMID: 37307576 PMCID: PMC10469547 DOI: 10.1093/plphys/kiad337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/14/2023]
Abstract
Understanding mechanisms of nutrient allocation in organisms requires precise knowledge of the spatiotemporal dynamics of small molecules in vivo. Genetically encoded sensors are powerful tools for studying nutrient distribution and dynamics, as they enable minimally invasive monitoring of nutrient steady-state levels in situ. Numerous types of genetically encoded sensors for nutrients have been designed and applied in mammalian cells and fungi. However, to date, their application for visualizing changing nutrient levels in planta remains limited. Systematic sensor-based approaches could provide the quantitative, kinetic information on tissue-specific, cellular, and subcellular distributions and dynamics of nutrients in situ that is needed for the development of theoretical nutrient flux models that form the basis for future crop engineering. Here, we review various approaches that can be used to measure nutrients in planta with an overview over conventional techniques, as well as genetically encoded sensors currently available for nutrient monitoring, and discuss their strengths and limitations. We provide a list of currently available sensors and summarize approaches for their application at the level of cellular compartments and organelles. When used in combination with bioassays on intact organisms and precise, yet destructive analytical methods, the spatiotemporal resolution of sensors offers the prospect of a holistic understanding of nutrient flux in plants.
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Affiliation(s)
- Mayuri Sadoine
- Institute of Cell and Interaction Biology, Heinrich-Heine Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Roberto De Michele
- Institute of Biosciences and Bioresources, National Research Council of Italy, Palermo 90129, Italy
| | - Milan Župunski
- Institute of Cell and Interaction Biology, Heinrich-Heine Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Guido Grossmann
- Institute of Cell and Interaction Biology, Heinrich-Heine Universität Düsseldorf, Düsseldorf 40225, Germany
- Cluster of Excellence on Plant Sciences, Heinrich-Heine Universität Düsseldorf, Düsseldorf 40225, Germany
| | - Vanessa Castro-Rodríguez
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Málaga 29071, Spain
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3
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Chen YN, Ho CH. Fluorescent Biosensor Imaging of Nitrate in Arabidopsis thaliana. Bio Protoc 2023; 13:e4743. [PMID: 37638290 PMCID: PMC10450734 DOI: 10.21769/bioprotoc.4743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/23/2023] [Accepted: 05/17/2023] [Indexed: 08/29/2023] Open
Abstract
Nitrate (NO3-) is an essential element and nutrient for plants and animals. Despite extensive studies on the regulation of nitrate uptake and downstream responses in various cells, our knowledge of the distribution of nitrogen forms in different root cell types and their cellular compartments is still limited. Previous physiological models have relied on in vitro biochemistry and metabolite level analysis, which limits the ability to differentiate between cell types and compartments. Here, to address this, we report a nuclear-localized, genetically encoded fluorescent biosensor, which we named nlsNitraMeter3.0, for the quantitative visualization of nitrate concentration and distribution at the cellular level in Arabidopsis thaliana. This biosensor was specifically designed for nitrate measurements, not nitrite. Through genetic engineering to create and select sensors using yeast, Xenopus oocyte, and Arabidopsis expression systems, we developed a reversible and highly specific nitrate sensor. This method, combined with fluorescence imaging systems such as confocal microscopy, allows for the understanding and monitoring of nitrate transporter activity in plant root cells in a minimally invasive manner. Furthermore, this approach enables the functional analysis of nitrate transporters and the measurement of nitrate distribution in plants, providing a valuable tool for plant biology research. In summary, we provide a protocol for sensor development and a biosensor that can be used to monitor nitrate levels in plants. Key features This protocol builds upon the concept of FRET biosensors for in vivo visualization of spatiotemporal nitrate levels at a cellular resolution. Nitrate levels can be quantified utilizing the biosensor in conjunction with either a plate reader or a fluorescence microscope.
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Affiliation(s)
- Yen-Ning Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Cheng-Hsun Ho
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
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4
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Park J, Abramowitz RG, Gwon S, Cheung LS. Exploring the Substrate Specificity of a Sugar Transporter with Biosensors and Cheminformatics. ACS Synth Biol 2023; 12:565-571. [PMID: 36719856 PMCID: PMC9942192 DOI: 10.1021/acssynbio.2c00571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Sugars will eventually be exported transporters (SWEETs) are conserved sugar transporters that play crucial roles in plant physiology and biotechnology. The genomes of flowering plants typically encode about 20 SWEET paralogs that can be classified into four clades. Clades I, II, and IV have been reported to favor hexoses, while clade III SWEETs prefer sucrose. However, the molecular features of substrates required for recognition by members of this family have not been investigated in detail. Here, we show that SweetTrac1, a previously reported biosensor constructed from the Clade I Arabidopsis thaliana SWEET1, can provide insight into the structural requirements for substrate recognition. The biosensor translates substrate binding to the transporter into a change in fluorescence, and its application in a small-molecule screen combined with cheminformatics uncovered 12 new sugars and their derivatives capable of eliciting a response. Furthermore, we confirmed that the wild-type transporter mediates cellular uptake of three of these species, including the diabetes drugs 1-deoxynojirimycin and voglibose. Our results show that SWEETs can recognize different furanoses, pyranoses, and acyclic sugars, illustrating the potential of combining biosensors and computational techniques to uncover the basis of substrate specificity.
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Affiliation(s)
- Jihyun Park
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ryan G. Abramowitz
- School
of Biological Sciences, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Sojeong Gwon
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Lily S. Cheung
- School
of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States,
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5
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Wu XX, Yuan DP, Chen H, Kumar V, Kang SM, Jia B, Xuan YH. Ammonium transporter 1 increases rice resistance to sheath blight by promoting nitrogen assimilation and ethylene signalling. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1085-1097. [PMID: 35170194 PMCID: PMC9129087 DOI: 10.1111/pbi.13789] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/01/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Sheath blight (ShB) significantly threatens rice yield production. However, the underlying mechanism of ShB defence in rice remains largely unknown. Here, we identified a highly ShB-susceptible mutant Ds-m which contained a mutation at the ammonium transporter 1;1 (AMT1;1) D358 N. AMT1;1 D358 N interacts with AMT1;1, AMT1;2 and AMT1;3 to inhibit the ammonium transport activity. The AMT1 RNAi was more susceptible and similar to the AMT1;1 D358 N mutant; however, plants with higher NH4+ uptake activity were less susceptible to ShB. Glutamine synthetase 1;1 (GS1;1) mutant gs1;1 and overexpressors (GS1;1 OXs) were more and less susceptible to ShB respectively. Furthermore, AMT1;1 overexpressor (AMT1;1 OX)/gs1;1 and gs1;1 exhibited a similar response to ShB, suggesting that ammonium assimilation rather than accumulation controls the ShB defence. Genetic and physiological assays further demonstrated that plants with higher amino acid or chlorophyll content promoted rice resistance to ShB. Interestingly, the expression of ethylene-related genes was higher in AMT1;1 OX and lower in RNAi mutants than in wild-type. Also, ethylene signalling positively regulated rice resistance to ShB and NH4+ uptake, suggesting that ethylene signalling acts downstream of AMT and also NH4+ uptake is under feedback control. Taken together, our data demonstrated that the AMT1 promotes rice resistance to ShB via the regulation of diverse metabolic and signalling pathways.
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Affiliation(s)
- Xian Xin Wu
- College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
| | - De Peng Yuan
- College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
| | - Huan Chen
- College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
| | - Vikranth Kumar
- Division of Plant SciencesUniversity of MissouriColumbiaMOUSA
| | | | - Baolei Jia
- School of BioengineeringState Key Laboratory of Biobased Material and Green PapermakingQilu University of Technology (Shandong Academy of Sciences)JinanChina
- Department of Life SciencesChung‐Ang UniversitySeoulSouth Korea
| | - Yuan Hu Xuan
- College of Plant ProtectionShenyang Agricultural UniversityShenyangChina
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6
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Chen YN, Ho CH. Concept of Fluorescent Transport Activity Biosensor for the Characterization of the Arabidopsis NPF1.3 Activity of Nitrate. SENSORS 2022; 22:s22031198. [PMID: 35161943 PMCID: PMC8839256 DOI: 10.3390/s22031198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/24/2022] [Accepted: 01/31/2022] [Indexed: 02/01/2023]
Abstract
The NRT1/PTR FAMILY (NPF) in Arabidopsis (Arabidopsis thaliana) plays a major role as a nitrate transporter. The first nitrate transporter activity biosensor NiTrac1 converted the dual-affinity nitrate transceptor NPF6.3 into fluorescence activity sensors. To test whether this approach is transferable to other members of this family, screening for genetically encoded fluorescence transport activity sensor was performed with the member of the NPF family in Arabidopsis. In this study, NPF1.3, an uncharacterized member of NPF in Arabidopsis, was converted into a transporter activity biosensor NiTrac-NPF1.3 that responds specifically to nitrate. The emission ratio change of NiTrac-NPF1.3 triggered by the addition of nitrate reveals the important function of NPF1.3 in nitrate transport in Arabidopsis. A functional analysis of Xenopus laevis oocytes confirmed that NPF1.3 plays a role as a nitrate transporter. This new technology is applicable in plant and medical research.
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7
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Development and quantitative analysis of a biosensor based on the Arabidopsis SWEET1 sugar transporter. Proc Natl Acad Sci U S A 2022; 119:2119183119. [PMID: 35046045 PMCID: PMC8794804 DOI: 10.1073/pnas.2119183119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2021] [Indexed: 01/01/2023] Open
Abstract
Transporters are the gatekeepers of the cell. Transporters facilitate the exchange of ions and metabolites between cellular and subcellular compartments, thus controlling processes from bacterial chemotaxis to the release of neurotransmitters. In plants, transporters have key roles in the allocation of carbon to nonphotosynthetic organs. Biosensors derived from transporters have been generated to monitor the activity of these proteins within the complex environment of the cell. However, a quantitative framework that reconciles molecular and cellular-level events to help interpret the response of biosensors is still lacking. Here, we created a sugar transporter biosensor and formulated a mathematical model to explain its response. These types of models can help realize multiscale, dynamic simulations of metabolite allocation to guide crop improvement. SWEETs are transporters with homologs in Archeae, plants, some fungi, and animals. As the only transporters known to facilitate the cellular release of sugars in plants, SWEETs play critical roles in the allocation of sugars from photosynthetic leaves to storage tissues in seeds, fruits, and tubers. Here, we report the design and use of genetically encoded biosensors to measure the activity of SWEETs. We created a SweetTrac1 sensor by inserting a circularly permutated green fluorescent protein into the Arabidopsis SWEET1, resulting in a chimera that translates substrate binding during the transport cycle into detectable changes in fluorescence intensity. We demonstrate that a combination of cell sorting and bioinformatics can accelerate the design of biosensors and formulate a mass action kinetics model to correlate the fluorescence response of SweetTrac1 with the transport of glucose. Our analysis suggests that SWEETs are low-affinity, symmetric transporters that can rapidly equilibrate intra- and extracellular concentrations of sugars. This approach can be extended to SWEET homologs and other transporters.
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8
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Sadoine M, Ishikawa Y, Kleist TJ, Wudick MM, Nakamura M, Grossmann G, Frommer WB, Ho CH. Designs, applications, and limitations of genetically encoded fluorescent sensors to explore plant biology. PLANT PHYSIOLOGY 2021; 187:485-503. [PMID: 35237822 PMCID: PMC8491070 DOI: 10.1093/plphys/kiab353] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/12/2021] [Indexed: 05/03/2023]
Abstract
The understanding of signaling and metabolic processes in multicellular organisms requires knowledge of the spatial dynamics of small molecules and the activities of enzymes, transporters, and other proteins in vivo, as well as biophysical parameters inside cells and across tissues. The cellular distribution of receptors, ligands, and activation state must be integrated with information about the cellular distribution of metabolites in relation to metabolic fluxes and signaling dynamics in order to achieve the promise of in vivo biochemistry. Genetically encoded sensors are engineered fluorescent proteins that have been developed for a wide range of small molecules, such as ions and metabolites, or to report biophysical processes, such as transmembrane voltage or tension. First steps have been taken to monitor the activity of transporters in vivo. Advancements in imaging technologies and specimen handling and stimulation have enabled researchers in plant sciences to implement sensor technologies in intact plants. Here, we provide a brief history of the development of genetically encoded sensors and an overview of the types of sensors available for quantifying and visualizing ion and metabolite distribution and dynamics. We further discuss the pros and cons of specific sensor designs, imaging systems, and sample manipulations, provide advice on the choice of technology, and give an outlook into future developments.
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Affiliation(s)
- Mayuri Sadoine
- Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Yuuma Ishikawa
- Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Thomas J. Kleist
- Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Michael M. Wudick
- Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
- Cluster of Excellence on Plant Sciences, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Masayoshi Nakamura
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Guido Grossmann
- Cluster of Excellence on Plant Sciences, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
- Institute for Cell and Interaction Biology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Wolf B. Frommer
- Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
- Cluster of Excellence on Plant Sciences, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Cheng-Hsun Ho
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
- Author for communication:
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9
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Waadt R, Kudla J, Kollist H. Multiparameter in vivo imaging in plants using genetically encoded fluorescent indicator multiplexing. PLANT PHYSIOLOGY 2021; 187:537-549. [PMID: 35237819 PMCID: PMC8491039 DOI: 10.1093/plphys/kiab399] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/03/2021] [Indexed: 05/20/2023]
Abstract
Biological processes are highly dynamic, and during plant growth, development, and environmental interactions, they occur and influence each other on diverse spatiotemporal scales. Understanding plant physiology on an organismic scale requires analyzing biological processes from various perspectives, down to the cellular and molecular levels. Ideally, such analyses should be conducted on intact and living plant tissues. Fluorescent protein (FP)-based in vivo biosensing using genetically encoded fluorescent indicators (GEFIs) is a state-of-the-art methodology for directly monitoring cellular ion, redox, sugar, hormone, ATP and phosphatidic acid dynamics, and protein kinase activities in plants. The steadily growing number of diverse but technically compatible genetically encoded biosensors, the development of dual-reporting indicators, and recent achievements in plate-reader-based analyses now allow for GEFI multiplexing: the simultaneous recording of multiple GEFIs in a single experiment. This in turn enables in vivo multiparameter analyses: the simultaneous recording of various biological processes in living organisms. Here, we provide an update on currently established direct FP-based biosensors in plants, discuss their functional principles, and highlight important biological findings accomplished by employing various approaches of GEFI-based multiplexing. We also discuss challenges and provide advice for FP-based biosensor analyses in plants.
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Affiliation(s)
- Rainer Waadt
- Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, Schlossplatz 7, Münster 48149, Germany
- Author for communication:
| | - Jörg Kudla
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, Schlossplatz 7, Münster 48149, Germany
| | - Hannes Kollist
- Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
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10
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Isoda R, Yoshinari A, Ishikawa Y, Sadoine M, Simon R, Frommer WB, Nakamura M. Sensors for the quantification, localization and analysis of the dynamics of plant hormones. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:542-557. [PMID: 33231903 PMCID: PMC7898640 DOI: 10.1111/tpj.15096] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/19/2020] [Indexed: 05/13/2023]
Abstract
Plant hormones play important roles in plant growth and development and physiology, and in acclimation to environmental changes. The hormone signaling networks are highly complex and interconnected. It is thus important to not only know where the hormones are produced, how they are transported and how and where they are perceived, but also to monitor their distribution quantitatively, ideally in a non-invasive manner. Here we summarize the diverse set of tools available for quantifying and visualizing hormone distribution and dynamics. We provide an overview over the tools that are currently available, including transcriptional reporters, degradation sensors, and luciferase and fluorescent sensors, and compare the tools and their suitability for different purposes.
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Affiliation(s)
- Reika Isoda
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8601Japan
| | - Akira Yoshinari
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8601Japan
| | - Yuuma Ishikawa
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8601Japan
- Molecular PhysiologyHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Mayuri Sadoine
- Molecular PhysiologyHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Rüdiger Simon
- Developmental GeneticsHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Wolf B. Frommer
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8601Japan
- Molecular PhysiologyHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Masayoshi Nakamura
- Institute of Transformative Bio‐Molecules (WPI‐ITbM)Nagoya UniversityChikusaNagoya464‐8601Japan
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11
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Yoshinari A, Moe-Lange J, Kleist TJ, Cartwright HN, Quint DA, Ehrhardt DW, Frommer WB, Nakamura M. Using Genetically Encoded Fluorescent Biosensors for Quantitative In Vivo Imaging. Methods Mol Biol 2020; 2200:303-322. [PMID: 33175384 DOI: 10.1007/978-1-0716-0880-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Fluorescent biosensors are powerful tools for tracking analytes or cellular processes in live organisms and allowing visualization of the spatial and temporal dynamics of cellular regulators. Fluorescent protein (FP)-based biosensors are extensively employed due to their high selectivity and low invasiveness. A variety of FP-based biosensors have been engineered and applied in plant research to visualize dynamic changes in pH, redox state, concentration of molecules (ions, sugars, peptides, ATP, reactive oxygen species, and phytohormones), and activity of transporters. In this chapter, we briefly summarize reported uses of FP-based biosensors in planta and show simple methods to monitor the dynamics of intracellular Ca2+ in Arabidopsis thaliana using a ratiometric genetically encoded Ca2+ indicator, MatryoshCaMP6s.
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Affiliation(s)
- Akira Yoshinari
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan
| | - Jacob Moe-Lange
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Thomas J Kleist
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Heather N Cartwright
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - David A Quint
- Center for Cellular and Biomolecular Machines (NSF-Crest), University of California, Merced, CA, USA
| | - David W Ehrhardt
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Wolf B Frommer
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan
- Institute for Molecular Physiology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Masayoshi Nakamura
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan.
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12
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Seo JS, Kim JK. Nitrogen molecular sensors and their use for screening mutants involved in nitrogen use efficiency. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 298:110587. [PMID: 32771146 DOI: 10.1016/j.plantsci.2020.110587] [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: 03/31/2020] [Revised: 06/22/2020] [Accepted: 06/27/2020] [Indexed: 06/11/2023]
Abstract
Nitrogen (N) is an essential macronutrient that is required for plant growth and development and has a major impact on crop yield and biomass. However, excessive application of N-based fertilizer results in environmental pollution and increases cultivation cost. A significant target of crop biotechnology is to develop crop varieties with improved N use efficiency (NUE), thereby overcoming these issues. While various aspects of plant N uptake and utilization have been studied, many factors that fundamentally affect NUE remain uncharacterized. For example, much remains to be learnt about the genes that determine NUE. One of the significant barriers to studying NUE is the absence of an in vivo N monitoring system. There are currently several methods for measuring plant N status, but they have limitations in terms of screening for NUE mutants and sensitive NUE assessment. Here, we describe strategies for generating and screening mutant pools using N molecular sensors, comprised of the rice genes OsALN and OsUPS1, the expression of which is sensitive to endogenous N status. Forward and reverse genetic approaches using the molecular N sensors will help identify molecular mechanisms underlying NUE.
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Affiliation(s)
- Jun Sung Seo
- Crop Biotechnology Institute, GreenBio Science and Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
| | - Ju-Kon Kim
- Crop Biotechnology Institute, GreenBio Science and Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
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13
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Brito AS, Neuhäuser B, Wintjens R, Marini AM, Boeckstaens M. Yeast filamentation signaling is connected to a specific substrate translocation mechanism of the Mep2 transceptor. PLoS Genet 2020; 16:e1008634. [PMID: 32069286 PMCID: PMC7048316 DOI: 10.1371/journal.pgen.1008634] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 02/28/2020] [Accepted: 01/28/2020] [Indexed: 11/18/2022] Open
Abstract
The dimorphic transition from the yeast to the filamentous form of growth allows cells to explore their environment for more suitable niches and is often crucial for the virulence of pathogenic fungi. In contrast to their Mep1/3 paralogues, fungal Mep2-type ammonium transport proteins of the conserved Mep-Amt-Rh family have been assigned an additional receptor role required to trigger the filamentation signal in response to ammonium scarcity. Here, genetic, kinetic and structure-function analyses were used to shed light on the poorly characterized signaling role of Saccharomyces cerevisiae Mep2. We show that Mep2 variants lacking the C-terminal tail conserve the ability to induce filamentation, revealing that signaling can proceed in the absence of exclusive binding of a putative partner to the largest cytosolic domain of the protein. Our data support that filamentation signaling requires the conformational changes accompanying substrate translocation through the pore crossing the hydrophobic core of Mep2. pHluorin reporter assays show that the transport activity of Mep2 and of non-signaling Mep1 differently affect yeast cytosolic pH in vivo, and that the unique pore variant Mep2H194E, with apparent uncoupling of transport and signaling functions, acquires increased ability of acidification. Functional characterization in Xenopus oocytes reveals that Mep2 mediates electroneutral substrate translocation while Mep1 performs electrogenic transport. Our findings highlight that the Mep2-dependent filamentation induction is connected to its specific transport mechanism, suggesting a role of pH in signal mediation. Finally, we show that the signaling process is conserved for the Mep2 protein from the human pathogen Candida albicans. Fungal Mep2-type ammonium transport proteins of the conserved Mep-Amt-Rh family that includes human Rhesus factors are specifically required to allow filamentation in response to ammonium limitation. These proteins were therefore assigned a receptor role while the underlying mechanism of signal transduction remains poorly understood. The “transceptor” property has subsequently been proposed to concern transporters of all kind of micro- and macro- nutrients in eukaryotes, from fungi to human. However, bringing the firm demonstration of their existence remains challenging as variants with full uncoupling of transport and receptor functions are difficult to obtain. Our data question the involvement of the C-terminal extremity of Saccharomyces cerevisiae Mep2 in the signal mediation leading to filamentation. If signaling partners exist, they should also bind to cytosolic loops and/or membrane-embedded domains. The capacity of Mep2 to enable filamentation is closely intertwined to the mechanism of substrate translocation through the pore of the hydrophobic core of the protein. In Xenopus oocytes, the transport activity of non-signaling Mep1 is electrogenic while it is electroneutral for Mep2, the latter likely translocating the weak base NH3, but not the proton released after NH4+ recognition and depronotation. We propose that given consequences of a Mep2-specific transport process, such as an intracellular pH modification, could be the underlying cause of the filamentation signal ensured by Mep2-type proteins.
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Affiliation(s)
- Ana Sofia Brito
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
| | - Benjamin Neuhäuser
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Stuttgart, Germany
| | - René Wintjens
- Unité Microbiologie, Chimie Bioorganique et Macromoléculaire, Département RD3, Faculté de Pharmacie, Université Libre de Bruxelles, Brussels, Belgium
| | - Anna Maria Marini
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
- * E-mail: (AMM); (MB)
| | - Mélanie Boeckstaens
- Biology of Membrane Transport Laboratory, Molecular Biology Department, Université Libre de Bruxelles, Gosselies, Belgium
- * E-mail: (AMM); (MB)
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14
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Tang RJ, Luan M, Wang C, Lhamo D, Yang Y, Zhao FG, Lan WZ, Fu AG, Luan S. Plant Membrane Transport Research in the Post-genomic Era. PLANT COMMUNICATIONS 2020; 1:100013. [PMID: 33404541 PMCID: PMC7747983 DOI: 10.1016/j.xplc.2019.100013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/14/2019] [Accepted: 12/06/2019] [Indexed: 05/17/2023]
Abstract
Membrane transport processes are indispensable for many aspects of plant physiology including mineral nutrition, solute storage, cell metabolism, cell signaling, osmoregulation, cell growth, and stress responses. Completion of genome sequencing in diverse plant species and the development of multiple genomic tools have marked a new era in understanding plant membrane transport at the mechanistic level. Genes coding for a galaxy of pumps, channels, and carriers that facilitate various membrane transport processes have been identified while multiple approaches are developed to dissect the physiological roles as well as to define the transport capacities of these transport systems. Furthermore, signaling networks dictating the membrane transport processes are established to fully understand the regulatory mechanisms. Here, we review recent research progress in the discovery and characterization of the components in plant membrane transport that take advantage of plant genomic resources and other experimental tools. We also provide our perspectives for future studies in the field.
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Affiliation(s)
- Ren-Jie Tang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Mingda Luan
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Chao Wang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Dhondup Lhamo
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Yang Yang
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Fu-Geng Zhao
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Wen-Zhi Lan
- Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Ai-Gen Fu
- College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Corresponding author
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15
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Michniewicz M, Ho CH, Enders TA, Floro E, Damodaran S, Gunther LK, Powers SK, Frick EM, Topp CN, Frommer WB, Strader LC. TRANSPORTER OF IBA1 Links Auxin and Cytokinin to Influence Root Architecture. Dev Cell 2019; 50:599-609.e4. [PMID: 31327740 DOI: 10.1016/j.devcel.2019.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/29/2019] [Accepted: 06/14/2019] [Indexed: 10/26/2022]
Abstract
Developmental processes that control root system architecture are critical for soil exploration by plants, allowing for uptake of water and nutrients. Conversion of the auxin precursor indole-3-butyric acid (IBA) to active auxin (indole-3-acetic acid; IAA) modulates lateral root formation. However, mechanisms governing IBA-to-IAA conversion have yet to be elucidated. We identified TRANSPORTER OF IBA1 (TOB1) as a vacuolar IBA transporter that limits lateral root formation. Moreover, TOB1, which is transcriptionally regulated by the phytohormone cytokinin, is necessary for the ability of cytokinin to exert inhibitory effects on lateral root production. The increased production of lateral roots in tob1 mutants, TOB1 transport of IBA into the vacuole, and cytokinin-regulated TOB1 expression provide a mechanism linking cytokinin signaling and IBA contribution to the auxin pool to tune root system architecture.
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Affiliation(s)
- Marta Michniewicz
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Cheng-Hsun Ho
- Institute for Molecular Physiology, Heinrich Heine Universität Düsseldorf, Institute for Biotransformative Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Tara A Enders
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Eric Floro
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Suresh Damodaran
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Lauren K Gunther
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Samantha K Powers
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Elizabeth M Frick
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | | | - Wolf B Frommer
- Institute for Molecular Physiology, Heinrich Heine Universität Düsseldorf, Institute for Biotransformative Molecules (WPI-ITbM), Nagoya University, Nagoya, Japan
| | - Lucia C Strader
- Department of Biology, Washington University, St. Louis, MO 63130, USA; Center for Engineering MechanoBiology, Washington University, St. Louis, MO 63130, USA; Center for Science & Engineering of Living Systems, Washington University, St. Louis, MO 63130, USA.
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16
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Abstract
With the rapid development of DNA synthesis and next-generation sequencing, synthetic biology that aims to standardize, modularize, and innovate cellular functions, has achieved vast progress. Here we review key advances in synthetic biology of the yeast Saccharomyces cerevisiae, which serves as an important eukaryal model organism and widely applied cell factory. This covers the development of new building blocks, i.e., promoters, terminators and enzymes, pathway engineering, tools developments, and gene circuits utilization. We will also summarize impacts of synthetic biology on both basic and applied biology, and end with further directions for advancing synthetic biology in yeast.
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Affiliation(s)
- Zihe Liu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing Key Laboratory of Bioprocess , Beijing University of Chemical Technology , Beijing 100029 , China
| | - Yueping Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing Key Laboratory of Bioprocess , Beijing University of Chemical Technology , Beijing 100029 , China
| | - Jens Nielsen
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing Key Laboratory of Bioprocess , Beijing University of Chemical Technology , Beijing 100029 , China.,Department of Biology and Biological Engineering , Chalmers University of Technology , Gothenburg SE41296 , Sweden.,Novo Nordisk Foundation Center for Biosustainability , Technical University of Denmark , Kongens Lyngby DK2800 , Denmark
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17
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Greenwald EC, Mehta S, Zhang J. Genetically Encoded Fluorescent Biosensors Illuminate the Spatiotemporal Regulation of Signaling Networks. Chem Rev 2018; 118:11707-11794. [PMID: 30550275 DOI: 10.1021/acs.chemrev.8b00333] [Citation(s) in RCA: 295] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cellular signaling networks are the foundation which determines the fate and function of cells as they respond to various cues and stimuli. The discovery of fluorescent proteins over 25 years ago enabled the development of a diverse array of genetically encodable fluorescent biosensors that are capable of measuring the spatiotemporal dynamics of signal transduction pathways in live cells. In an effort to encapsulate the breadth over which fluorescent biosensors have expanded, we endeavored to assemble a comprehensive list of published engineered biosensors, and we discuss many of the molecular designs utilized in their development. Then, we review how the high temporal and spatial resolution afforded by fluorescent biosensors has aided our understanding of the spatiotemporal regulation of signaling networks at the cellular and subcellular level. Finally, we highlight some emerging areas of research in both biosensor design and applications that are on the forefront of biosensor development.
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Affiliation(s)
- Eric C Greenwald
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Sohum Mehta
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
| | - Jin Zhang
- University of California , San Diego, 9500 Gilman Drive, BRFII , La Jolla , CA 92093-0702 , United States
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18
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Geisler M. Seeing is better than believing: visualization of membrane transport in plants. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:104-112. [PMID: 30253307 DOI: 10.1016/j.pbi.2018.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/30/2018] [Accepted: 09/03/2018] [Indexed: 05/27/2023]
Abstract
Recently, the plant transport field has shifted their research focus toward a more integrative investigation of transport networks thought to provide the basis for long-range transport routes. Substantial progress was provided by of a series of elegant techniques that allow for a visualization or prediction of substrate movements in plant tissues in contrast to established quantitative methods offering low spatial resolution. These methods are critically evaluated in respect to their spatio-temporal resolution, invasiveness, dynamics and overall quality. Current limitations of transport route predictions-based on transporter locations and transport modeling are addressed. Finally, the potential of new tools that have not yet been fully implemented into plant research is indicated.
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Affiliation(s)
- Markus Geisler
- University of Fribourg, Department of Biology, Chemin du Musée 10, CH-1700 Fribourg, Switzerland.
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19
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Hilleary R, Choi WG, Kim SH, Lim SD, Gilroy S. Sense and sensibility: the use of fluorescent protein-based genetically encoded biosensors in plants. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:32-38. [PMID: 30041101 DOI: 10.1016/j.pbi.2018.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/27/2018] [Accepted: 07/05/2018] [Indexed: 05/09/2023]
Abstract
Fluorescent protein-based biosensors are providing us with an unprecedented, quantitative view of the dynamic nature of the cellular networks that lie at the heart of plant biology. Such bioreporters can visualize the spatial and temporal kinetics of cellular regulators such as Ca2+ and H+, plant hormones and even allow membrane transport activities to be monitored in real time in living plant cells. The fast pace of their development is making these tools increasingly sensitive and easy to use and the rapidly expanding biosensor toolkit offers great potential for new insights into a wide range of plant regulatory processes. We suggest a checklist of controls that should help avoid some of the more cryptic issues with using these bioreporter technologies.
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Affiliation(s)
- Richard Hilleary
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, USA
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia Street, University of Nevada, Reno, NV 89557, USA
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia Street, University of Nevada, Reno, NV 89557, USA
| | - Sung Don Lim
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia Street, University of Nevada, Reno, NV 89557, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Drive, Madison, WI 53706, USA.
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20
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Metabolic heterogeneity in clonal microbial populations. Curr Opin Microbiol 2018; 45:30-38. [DOI: 10.1016/j.mib.2018.02.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 11/22/2022]
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21
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In vivo biosensors: mechanisms, development, and applications. ACTA ACUST UNITED AC 2018; 45:491-516. [DOI: 10.1007/s10295-018-2004-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/30/2017] [Indexed: 01/09/2023]
Abstract
Abstract
In vivo biosensors can recognize and respond to specific cellular stimuli. In recent years, biosensors have been increasingly used in metabolic engineering and synthetic biology, because they can be implemented in synthetic circuits to control the expression of reporter genes in response to specific cellular stimuli, such as a certain metabolite or a change in pH. There are many types of natural sensing devices, which can be generally divided into two main categories: protein-based and nucleic acid-based. Both can be obtained either by directly mining from natural genetic components or by engineering the existing genetic components for novel specificity or improved characteristics. A wide range of new technologies have enabled rapid engineering and discovery of new biosensors, which are paving the way for a new era of biotechnological progress. Here, we review recent advances in the design, optimization, and applications of in vivo biosensors in the field of metabolic engineering and synthetic biology.
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22
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Walia A, Waadt R, Jones AM. Genetically Encoded Biosensors in Plants: Pathways to Discovery. ANNUAL REVIEW OF PLANT BIOLOGY 2018; 69:497-524. [PMID: 29719164 DOI: 10.1146/annurev-arplant-042817-040104] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Genetically encoded biosensors that directly interact with a molecule of interest were first introduced more than 20 years ago with fusion proteins that served as fluorescent indicators for calcium ions. Since then, the technology has matured into a diverse array of biosensors that have been deployed to improve our spatiotemporal understanding of molecules whose dynamics have profound influence on plant physiology and development. In this review, we address several types of biosensors with a focus on genetically encoded calcium indicators, which are now the most diverse and advanced group of biosensors. We then consider the discoveries in plant biology made by using biosensors for calcium, pH, reactive oxygen species, redox conditions, primary metabolites, phytohormones, and nutrients. These discoveries were dependent on the engineering, characterization, and optimization required to develop a successful biosensor; they were also dependent on the methodological developments required to express, detect, and analyze the readout of such biosensors.
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Affiliation(s)
- Ankit Walia
- Sainsbury Laboratory, Cambridge University, Cambridge CB2 1LR, United Kingdom;
| | - Rainer Waadt
- Centre for Organismal Studies, Ruprecht-Karls-Universität Heidelberg, Heidelberg 69120, Germany
| | - Alexander M Jones
- Sainsbury Laboratory, Cambridge University, Cambridge CB2 1LR, United Kingdom;
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23
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Pflüger T, Hernández CF, Lewe P, Frank F, Mertens H, Svergun D, Baumstark MW, Lunin VY, Jetten MSM, Andrade SLA. Signaling ammonium across membranes through an ammonium sensor histidine kinase. Nat Commun 2018; 9:164. [PMID: 29323112 PMCID: PMC5764959 DOI: 10.1038/s41467-017-02637-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 12/15/2017] [Indexed: 01/07/2023] Open
Abstract
Sensing and uptake of external ammonium is essential for anaerobic ammonium-oxidizing (anammox) bacteria, and is typically the domain of the ubiquitous Amt/Rh ammonium transporters. Here, we report on the structure and function of an ammonium sensor/transducer from the anammox bacterium "Candidatus Kuenenia stuttgartiensis" that combines a membrane-integral ammonium transporter domain with a fused histidine kinase. It contains a high-affinity ammonium binding site not present in assimilatory Amt proteins. The levels of phosphorylated histidine in the kinase are coupled to the presence of ammonium, as conformational changes during signal recognition by the Amt module are transduced internally to modulate the kinase activity. The structural analysis of this ammonium sensor by X-ray crystallography and small-angle X-ray-scattering reveals a flexible, bipartite system that recruits a large uptake transporter as a sensory module and modulates its functionality to achieve a mechanistic coupling to a kinase domain in order to trigger downstream signaling events.
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Affiliation(s)
- Tobias Pflüger
- Institute for Biochemistry, University of Freiburg, Albertstr. 21, Freiburg, 79104, Germany
| | - Camila F Hernández
- Institute for Biochemistry, University of Freiburg, Albertstr. 21, Freiburg, 79104, Germany
| | - Philipp Lewe
- Institute for Biochemistry, University of Freiburg, Albertstr. 21, Freiburg, 79104, Germany
| | - Fabian Frank
- Institute for Biochemistry, University of Freiburg, Albertstr. 21, Freiburg, 79104, Germany
| | - Haydyn Mertens
- European Molecular Biology Laboratory, Hamburg Unit, EMBL c/o DESY, Notkestr. 85, Hamburg, D-22603, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Unit, EMBL c/o DESY, Notkestr. 85, Hamburg, D-22603, Germany
| | - Manfred W Baumstark
- Center for Medicine, Institute for Exercise and Occupational Medicine, Medical Center, University of Freiburg, Hugstetterstr. 55, Freiburg, 79106, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, 79106, Germany
| | - Vladimir Y Lunin
- Institute of Mathematical Problems of Biology RAS, Keldysh Institute of Applied Mathematics of Russian Academy of Sciences, Vitkevicha str. 1, Pushchino, 142290, Russia
| | - Mike S M Jetten
- Department of Microbiology, Radboud University, Institute for Water and Wetland Research, Heyendaalseweg 135, Nijmegen, NL-6525 AJ, The Netherlands
| | - Susana L A Andrade
- Institute for Biochemistry, University of Freiburg, Albertstr. 21, Freiburg, 79104, Germany. .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestr. 1, Freiburg, 79104, Germany.
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24
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Lee DK, Redillas MCFR, Jung H, Choi S, Kim YS, Kim JK. A Nitrogen Molecular Sensing System, Comprised of the ALLANTOINASE and UREIDE PERMEASE 1 Genes, Can Be Used to Monitor N Status in Rice. FRONTIERS IN PLANT SCIENCE 2018; 9:444. [PMID: 29720986 PMCID: PMC5915567 DOI: 10.3389/fpls.2018.00444] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/21/2018] [Indexed: 05/14/2023]
Abstract
Nitrogen (N) is an essential nutrient for plant growth and development, but its concentration in the soil is often insufficient for optimal crop production. Consequently, improving N utilization in crops is considered as a major target in agricultural biotechnology. However, much remains to be learnt about crop N metabolism for application. In this study, we have developed a molecular sensor system to monitor the N status in rice (Oryza sativa). We first examined the role of the ureide, allantoin, which is catabolized into allantoin-derived metabolites and used as an N source under low N conditions. The expression levels of two genes involved in ureide metabolism, ALLANTOINASE (OsALN) and UREIDE PERMEASE 1 (OsUPS1), were highly responsive to the N status. OsALN was rapidly up-regulated under low N conditions, whereas OsUPS1 was up-regulated under high N conditions. Taking advantage of the responses of these two genes to N status, we generated transgenic rice plants harboring the molecular N sensors, proALN::ALN-LUC2 and proUPS1::UPS1-LUC2, comprising the gene promoters driving expression of the luciferase reporter. We observed that expression of the transgenes mimicked transcriptional regulation of the endogenous OsALN and OsUPS1 genes in response to exogenous N status. Importantly, the molecular N sensors showed similar levels of specificity to nitrate and ammonium, from which we infer their sensing abilities. Transgenic rice plants expressing the proUPS1::UPS1-LUC2 sensor showed strong luminescence under high exogenous N conditions (>1 mM), whereas transgenic plants expressing the proALN::ALN-LUC2 sensor showed strong luminescence under low exogenous N conditions (<0.1 mM). High exogenous N (>1 mM) substantially increased internal ammonium and nitrate levels, whereas low exogenous N (<0.1 mM) had no effect on internal ammonium and nitrate levels, indicating the luminescence signals of molecular sensors reflect internal N status in rice. Thus, proALN::ALN-LUC2 and proUPS1::UPS1-LUC2 represent N molecular sensors that operate over a physiological and developmental range in rice.
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Affiliation(s)
| | | | | | | | | | - Ju-Kon Kim
- *Correspondence: Dong-Keun Lee, Ju-Kon Kim,
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25
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Liu Y, Liu Y, Wang M. Design, Optimization and Application of Small Molecule Biosensor in Metabolic Engineering. Front Microbiol 2017; 8:2012. [PMID: 29089935 PMCID: PMC5651080 DOI: 10.3389/fmicb.2017.02012] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/29/2017] [Indexed: 11/13/2022] Open
Abstract
The development of synthetic biology and metabolic engineering has painted a great future for the bio-based economy, including fuels, chemicals, and drugs produced from renewable feedstocks. With the rapid advance of genome-scale modeling, pathway assembling and genome engineering/editing, our ability to design and generate microbial cell factories with various phenotype becomes almost limitless. However, our lack of ability to measure and exert precise control over metabolite concentration related phenotypes becomes a bottleneck in metabolic engineering. Genetically encoded small molecule biosensors, which provide the means to couple metabolite concentration to measurable or actionable outputs, are highly promising solutions to the bottleneck. Here we review recent advances in the design, optimization and application of small molecule biosensor in metabolic engineering, with particular focus on optimization strategies for transcription factor (TF) based biosensors.
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Affiliation(s)
- Yang Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Ye Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Meng Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
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26
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Okumoto S, Versaw W. Genetically encoded sensors for monitoring the transport and concentration of nitrogen-containing and phosphorus-containing molecules in plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 39:129-135. [PMID: 28750256 DOI: 10.1016/j.pbi.2017.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/06/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
Nitrogen and phosphorus are macronutrients indispensable for plant growth. The acquisition and reallocation of both elements require a multitude of dedicated transporters that specifically recognize inorganic and organic forms of nitrogen and phosphorous. Although many transporters have been discovered through elegant screening processes and sequence homology, many remain uncharacterized for their functions in planta. Genetically encoded sensors for nitrogen and phosphorous molecules offer a unique opportunity for studying transport mechanisms that were previously inaccessible. In the past few years, sensors for some of the key nitrogen molecules became available, and many improvements have been made for existing sensors for phosphorus molecules. Methodologies for detailed in vivo analysis also improved. We summarize the recent improvements in genetically encoded sensors for nitrogen and phosphorus molecules, and the discoveries made by using such sensors.
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Affiliation(s)
- Sakiko Okumoto
- Department of Soil and Crop Sciences, Texas A&M University, HEEP Center, College Station, TX 77843 USA.
| | - Wayne Versaw
- Department of Biology, Texas A&M University, Biological Sciences Building East, College Station, TX 77843 USA
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27
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Rizza A, Walia A, Lanquar V, Frommer WB, Jones AM. In vivo gibberellin gradients visualized in rapidly elongating tissues. NATURE PLANTS 2017; 3:803-813. [PMID: 28970478 DOI: 10.1038/s41477-017-0021-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/24/2017] [Indexed: 05/27/2023]
Abstract
The phytohormone gibberellin (GA) is a key regulator of plant growth and development. Although the upstream regulation and downstream responses to GA vary across cells and tissues, developmental stages and environmental conditions, the spatiotemporal distribution of GA in vivo remains unclear. Using a combinatorial screen in yeast, we engineered an optogenetic biosensor, GIBBERELLIN PERCEPTION SENSOR 1 (GPS1), that senses nanomolar levels of bioactive GAs. Arabidopsis thaliana plants expressing a nuclear localized GPS1 report on GAs at the cellular level. GA gradients were correlated with gradients of cell length in rapidly elongating roots and dark-grown hypocotyls. In roots, accumulation of exogenously applied GA also correlated with cell length, intimating that a root GA gradient can be established independently of GA biosynthesis. In hypocotyls, GA levels were reduced in a phytochrome interacting factor (pif) quadruple mutant in the dark and increased in a phytochrome double mutant in the light, indicating that PIFs elevate GA in the dark and that phytochrome inhibition of PIFs could lower GA in the light. As GA signalling directs hypocotyl elongation largely through promoting PIF activity, PIF promotion of GA accumulation represents a positive feedback loop within the molecular framework driving rapid hypocotyl growth.
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Affiliation(s)
- Annalisa Rizza
- Sainsbury Laboratory, Cambridge University, Cambridge, UK
| | - Ankit Walia
- Sainsbury Laboratory, Cambridge University, Cambridge, UK
| | - Viviane Lanquar
- Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, USA
| | - Wolf B Frommer
- Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, USA.
- Institute for Molecular Physiology, Heinrich Heine Universität, 40225, Düsseldorf, Germany.
- Max Planck Institute for Plant Breeding Research, 50829, Cologne, Germany.
| | - Alexander M Jones
- Sainsbury Laboratory, Cambridge University, Cambridge, UK.
- Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, USA.
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Ratiometric Matryoshka biosensors from a nested cassette of green- and orange-emitting fluorescent proteins. Nat Commun 2017; 8:431. [PMID: 28874729 PMCID: PMC5585204 DOI: 10.1038/s41467-017-00400-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 06/24/2017] [Indexed: 01/25/2023] Open
Abstract
Sensitivity, dynamic and detection range as well as exclusion of expression and instrumental artifacts are critical for the quantitation of data obtained with fluorescent protein (FP)-based biosensors in vivo. Current biosensors designs are, in general, unable to simultaneously meet all these criteria. Here, we describe a generalizable platform to create dual-FP biosensors with large dynamic ranges by employing a single FP-cassette, named GO-(Green-Orange) Matryoshka. The cassette nests a stable reference FP (large Stokes shift LSSmOrange) within a reporter FP (circularly permuted green FP). GO- Matryoshka yields green and orange fluorescence upon blue excitation. As proof of concept, we converted existing, single-emission biosensors into a series of ratiometric calcium sensors (MatryoshCaMP6s) and ammonium transport activity sensors (AmTryoshka1;3). We additionally identified the internal acid-base equilibrium as a key determinant of the GCaMP dynamic range. Matryoshka technology promises flexibility in the design of a wide spectrum of ratiometric biosensors and expanded in vivo applications.Single fluorescent protein biosensors are susceptible to expression and instrumental artifacts. Here Ast et al. describe a dual fluorescent protein design whereby a reference fluorescent protein is nested within a reporter fluorescent protein to control for such artifacts while preserving sensitivity and dynamic range.
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Barnett LM, Hughes TE, Drobizhev M. Deciphering the molecular mechanism responsible for GCaMP6m's Ca2+-dependent change in fluorescence. PLoS One 2017; 12:e0170934. [PMID: 28182677 PMCID: PMC5300113 DOI: 10.1371/journal.pone.0170934] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/12/2017] [Indexed: 11/19/2022] Open
Abstract
The goal of this work is to determine how GCaMP6m's fluorescence is altered in response to Ca2+-binding. Our detailed spectroscopic study reveals the simplest explanation for how GCaMP6m changes fluorescence in response to Ca2+ is with a four-state model, in which a Ca2+-dependent change of the chromophore protonation state, due to a shift in pKa, is the predominant factor. The pKa shift is quantitatively explained by a change in electrostatic potential around the chromophore due to the conformational changes that occur in the protein when calmodulin binds Ca2+ and interacts with the M13 peptide. The absolute pKa values for the Ca2+-free and Ca2+-saturated states of GCaMP6m are critical to its high signal-to-noise ratio. This mechanism has important implications for further improvements to GCaMP6m and potentially for other similarly designed biosensors.
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Affiliation(s)
- Lauren M. Barnett
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States
| | - Thomas E. Hughes
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States
| | - Mikhail Drobizhev
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana, United States
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Jacoby RP, Millar AH, Taylor NL. Opportunities for wheat proteomics to discover the biomarkers for respiration-dependent biomass production, stress tolerance and cytoplasmic male sterility. J Proteomics 2016; 143:36-44. [DOI: 10.1016/j.jprot.2016.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/10/2016] [Accepted: 02/17/2016] [Indexed: 01/23/2023]
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Provart NJ, Alonso J, Assmann SM, Bergmann D, Brady SM, Brkljacic J, Browse J, Chapple C, Colot V, Cutler S, Dangl J, Ehrhardt D, Friesner JD, Frommer WB, Grotewold E, Meyerowitz E, Nemhauser J, Nordborg M, Pikaard C, Shanklin J, Somerville C, Stitt M, Torii KU, Waese J, Wagner D, McCourt P. 50 years of Arabidopsis research: highlights and future directions. THE NEW PHYTOLOGIST 2016; 209:921-44. [PMID: 26465351 DOI: 10.1111/nph.13687] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/24/2015] [Indexed: 05/14/2023]
Abstract
922 I. 922 II. 922 III. 925 IV. 925 V. 926 VI. 927 VII. 928 VIII. 929 IX. 930 X. 931 XI. 932 XII. 933 XIII. Natural variation and genome-wide association studies 934 XIV. 934 XV. 935 XVI. 936 XVII. 937 937 References 937 SUMMARY: The year 2014 marked the 25(th) International Conference on Arabidopsis Research. In the 50 yr since the first International Conference on Arabidopsis Research, held in 1965 in Göttingen, Germany, > 54 000 papers that mention Arabidopsis thaliana in the title, abstract or keywords have been published. We present herein a citational network analysis of these papers, and touch on some of the important discoveries in plant biology that have been made in this powerful model system, and highlight how these discoveries have then had an impact in crop species. We also look to the future, highlighting some outstanding questions that can be readily addressed in Arabidopsis. Topics that are discussed include Arabidopsis reverse genetic resources, stock centers, databases and online tools, cell biology, development, hormones, plant immunity, signaling in response to abiotic stress, transporters, biosynthesis of cells walls and macromolecules such as starch and lipids, epigenetics and epigenomics, genome-wide association studies and natural variation, gene regulatory networks, modeling and systems biology, and synthetic biology.
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Affiliation(s)
- Nicholas J Provart
- Department of Cell & Systems Biology/CAGEF, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Jose Alonso
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Siobhan M Brady
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
| | - Jelena Brkljacic
- Arabidopsis Biological Resource Center, The Ohio State University, Columbus, OH, 43210, USA
| | - John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Vincent Colot
- Departement de Biologie École Normale Supérieure, Biologie Moleculaire des Organismes Photosynthetiques, F-75230, Paris, France
| | - Sean Cutler
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92507, USA
| | - Jeff Dangl
- Department of Biology and Howard Hughes Medical Institute, Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - David Ehrhardt
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Joanna D Friesner
- Department of Plant Biology, Agricultural Sustainability Institute, University of California, Davis, CA, 95616, USA
| | - Wolf B Frommer
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Erich Grotewold
- Center for Applied Plant Science, The Ohio State University, Columbus, OH, 43210, USA
| | - Elliot Meyerowitz
- Division of Biology and Biological Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Jennifer Nemhauser
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Magnus Nordborg
- Gregor Mendel Institute of Molecular Plant Biology, A-1030, Vienna, Austria
| | - Craig Pikaard
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Chris Somerville
- Energy Biosciences Institute, University of California, Berkeley, CA, 94704, USA
| | - Mark Stitt
- Metabolic Networks Department, Max Planck Institute for Molecular Plant Physiology, D-14476, Potsdam, Germany
| | - Keiko U Torii
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Jamie Waese
- Department of Cell & Systems Biology/CAGEF, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Doris Wagner
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Peter McCourt
- Department of Cell & Systems Biology/CAGEF, University of Toronto, Toronto, ON, M5S 3B2, Canada
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Development of biosensors and their application in metabolic engineering. Curr Opin Chem Biol 2015; 28:1-8. [DOI: 10.1016/j.cbpa.2015.05.013] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/04/2015] [Accepted: 05/14/2015] [Indexed: 01/30/2023]
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Neuhäuser B, Dynowski M, Ludewig U. Switching substrate specificity of AMT/MEP/ Rh proteins. Channels (Austin) 2015; 8:496-502. [PMID: 25483282 DOI: 10.4161/19336950.2014.967618] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In organisms from all kingdoms of life, ammonia and its conjugated ion ammonium are transported across membranes by proteins of the AMT/Rh family. Efficient and successful growth often depends on sufficient ammonium nutrition. The proteins mediating this transport, the so called Ammonium Transporter (AMT) or Rhesus like (Rh) proteins, share a very similar trimeric overall structure and a high sequence similarity even throughout the kingdoms. Even though structural components of the transport mechanism, like an external substrate recruitment site, an essential twin histidine pore motif, a phenylalanine gate and the hydrophobic pore are strongly conserved and have been analyzed in detail by molecular dynamic simulations and mutational studies, the substrate(s), which pass the central pores of the AMT/Rh subunits, NH4(+), NH3 + H(+), NH4(+) + H(+) or NH3, are still a matter of debate for most proteins, including the best characterized AmtB protein from Escherichia coli. The lack of a robust expression system for functional analysis has hampered proof of structural and mutational studies, although the NH3 transport function for Rh-like proteins is rarely disputed. In plant transporters belonging to the subfamily AMT1, transport is associated with electrical currents, while some plant transporters, notably of the AMT2 type, were suggested to transport NH3 across the membrane, without associated ionic currents. Here we summarize data in favor of each substrate for the distinct AMT/Rh classes, discuss mutants and how they differ in structure and functionality. A common mechanism with deprotonation and subsequent NH3 transport through the central subunit pore is suggested.
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Affiliation(s)
- Benjamin Neuhäuser
- a Institute of Crop Science; Nutritional Crop Physiology ; University of Hohenheim ; Stuttgart , Germany
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Ast C, De Michele R, Kumke MU, Frommer WB. Single-fluorophore membrane transport activity sensors with dual-emission read-out. eLife 2015; 4:e07113. [PMID: 26090909 PMCID: PMC4491562 DOI: 10.7554/elife.07113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/18/2015] [Indexed: 01/28/2023] Open
Abstract
We recently described a series of genetically encoded, single-fluorophore-based sensors, termed AmTrac and MepTrac, which monitor membrane transporter activity in vivo (De Michele et al., 2013). However, being intensiometric, AmTrac and Meptrac are limited in their use for quantitative studies. Here, we characterized the photophysical properties (steady-state and time-resolved fluorescence spectroscopy as well as anisotropy decay analysis) of different AmTrac sensors with diverging fluorescence properties in order to generate improved, ratiometric sensors. By replacing key amino acid residues in AmTrac we constructed a set of dual-emission AmTrac sensors named deAmTracs. deAmTracs show opposing changes of blue and green emission with almost doubled emission ratio upon ammonium addition. The response ratio of the deAmTracs correlated with transport activity in mutants with altered capacity. Our results suggest that partial disruption of distance-dependent excited-state proton transfer is important for the successful generation of single-fluorophore-based dual-emission sensors.
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Affiliation(s)
- Cindy Ast
- Department of Plant Biology, Carnegie Institution for Science, Stanford California, United States
| | - Roberto De Michele
- Institute of Biosciences and Bioresources, Italian National Research Council, Palermo, Italy
| | - Michael U Kumke
- Department of Physical Chemistry, Institute of Chemistry, University of Potsdam, Potsdam, Germany
| | - Wolf B Frommer
- Department of Plant Biology, Carnegie Institution for Science, Stanford California, United States
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Abstract
Soluble sugars serve five main purposes in multicellular organisms: as sources of carbon skeletons, osmolytes, signals, and transient energy storage and as transport molecules. Most sugars are derived from photosynthetic organisms, particularly plants. In multicellular organisms, some cells specialize in providing sugars to other cells (e.g., intestinal and liver cells in animals, photosynthetic cells in plants), whereas others depend completely on an external supply (e.g., brain cells, roots and seeds). This cellular exchange of sugars requires transport proteins to mediate uptake or release from cells or subcellular compartments. Thus, not surprisingly, sugar transport is critical for plants, animals, and humans. At present, three classes of eukaryotic sugar transporters have been characterized, namely the glucose transporters (GLUTs), sodium-glucose symporters (SGLTs), and SWEETs. This review presents the history and state of the art of sugar transporter research, covering genetics, biochemistry, and physiology-from their identification and characterization to their structure, function, and physiology. In humans, understanding sugar transport has therapeutic importance (e.g., addressing diabetes or limiting access of cancer cells to sugars), and in plants, these transporters are critical for crop yield and pathogen susceptibility.
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Affiliation(s)
- Li-Qing Chen
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305;
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Reddy MM, Ulaganathan K. Nitrogen Nutrition, Its Regulation and Biotechnological Approaches to Improve Crop Productivity. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ajps.2015.618275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yuan L, Grotewold E. Metabolic engineering to enhance the value of plants as green factories. Metab Eng 2014; 27:83-91. [PMID: 25461830 DOI: 10.1016/j.ymben.2014.11.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 11/08/2014] [Accepted: 11/11/2014] [Indexed: 12/21/2022]
Abstract
The promise of plants to serve as the green factories of the future is ever increasing. Plants have been used traditionally for construction, energy, food and feed. Bioactive compounds primarily derived from specialized plant metabolism continue to serve as important scaffold molecules for pharmaceutical drug production. Yet, the past few years have witnessed a growing interest on plants as the ultimate harvesters of carbon and energy from the sun, providing carbohydrate and lipid biofuels that would contribute to balancing atmospheric carbon. How can the metabolic output from plants be increased even further, and what are the bottlenecks? Here, we present what we perceive to be the main opportunities and challenges associated with increasing the efficiency of plants as chemical factories. We offer some perspectives on when it makes sense to use plants as production systems because the amount of biomass needed makes any other system unfeasible. However, there are other instances in which plants serve as great sources of biological catalysts, yet are not necessarily the best-suited systems for production. We also present emerging opportunities for manipulating plant genomes to make plant synthetic biology a reality.
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Affiliation(s)
- Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, 1401 University Drive, Lexington, KY 40546, United States
| | - Erich Grotewold
- Center for Applied Plant Sciences (CAPS), Department of Molecular Genetics and Department of Horticulture and Crop Science, The Ohio State University, 012 Rightmire Hall, 1060 Carmack Rd, Columbus, OH 43210, United States.
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Ruberti C, Barizza E, Bodner M, La Rocca N, De Michele R, Carimi F, Schiavo FL, Zottini M. Mitochondria change dynamics and morphology during grapevine leaf senescence. PLoS One 2014; 9:e102012. [PMID: 25009991 PMCID: PMC4092070 DOI: 10.1371/journal.pone.0102012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/12/2014] [Indexed: 11/29/2022] Open
Abstract
Leaf senescence is the last stage of development of an organ and is aimed to its ordered disassembly and nutrient reallocation. Whereas chlorophyll gradually degrades during senescence in leaves, mitochondria need to maintain active to sustain the energy demands of senescing cells. Here we analysed the motility and morphology of mitochondria in different stages of senescence in leaves of grapevine (Vitis vinifera), by stably expressing a GFP (green fluorescent protein) reporter targeted to these organelles. Results show that mitochondria were less dynamic and markedly changed morphology during senescence, passing from the elongated, branched structures found in mature leaves to enlarged and sparse organelles in senescent leaves. Progression of senescence in leaves was not synchronous, since changes in mitochondria from stomata were delayed. Mitochondrial morphology was also analysed in grapevine cell cultures. Mitochondria from cells at the end of their growth curve resembled those from senescing leaves, suggesting that cell cultures might represent a useful model system for senescence. Additionally, senescence-associated mitochondrial changes were observed in plants treated with high concentrations of cytokinins. Overall, morphology and dynamics of mitochondria might represent a reliable senescence marker for plant cells.
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Affiliation(s)
- Cristina Ruberti
- Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy
| | - Elisabetta Barizza
- Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy
| | - Martina Bodner
- Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy
| | - Nicoletta La Rocca
- Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy
| | - Roberto De Michele
- Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche (CNR-IBBR), Corso Calatafimi, Palermo, Italy
| | - Francesco Carimi
- Istituto di Bioscienze e Biorisorse, Consiglio Nazionale delle Ricerche (CNR-IBBR), Corso Calatafimi, Palermo, Italy
| | | | - Michela Zottini
- Dipartimento di Biologia, Università degli Studi di Padova, Padova, Italy
- * E-mail:
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Sozzani R, Busch W, Spalding EP, Benfey PN. Advanced imaging techniques for the study of plant growth and development. TRENDS IN PLANT SCIENCE 2014; 19:304-10. [PMID: 24434036 PMCID: PMC4008707 DOI: 10.1016/j.tplants.2013.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/29/2013] [Accepted: 12/11/2013] [Indexed: 05/07/2023]
Abstract
A variety of imaging methodologies are being used to collect data for quantitative studies of plant growth and development from living plants. Multi-level data, from macroscopic to molecular, and from weeks to seconds, can be acquired. Furthermore, advances in parallelized and automated image acquisition enable the throughput to capture images from large populations of plants under specific growth conditions. Image-processing capabilities allow for 3D or 4D reconstruction of image data and automated quantification of biological features. These advances facilitate the integration of imaging data with genome-wide molecular data to enable systems-level modeling.
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Affiliation(s)
- Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Wolfgang Busch
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Edgar P Spalding
- Department of Botany, University of Wisconsin, Madison, WI 53706 USA
| | - Philip N Benfey
- Department of Biology, Duke Center for Systems Biology, and Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA.
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Jones AM, Danielson JA, Manojkumar SN, Lanquar V, Grossmann G, Frommer WB. Abscisic acid dynamics in roots detected with genetically encoded FRET sensors. eLife 2014; 3:e01741. [PMID: 24737862 PMCID: PMC3985517 DOI: 10.7554/elife.01741] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cytosolic hormone levels must be tightly controlled at the level of influx, efflux, synthesis, degradation and compartmentation. To determine ABA dynamics at the single cell level, FRET sensors (ABACUS) covering a range ∼0.2–800 µM were engineered using structure-guided design and a high-throughput screening platform. When expressed in yeast, ABACUS1 detected concentrative ABA uptake mediated by the AIT1/NRT1.2 transporter. Arabidopsis roots expressing ABACUS1-2µ (Kd∼2 µM) and ABACUS1-80µ (Kd∼80 µM) respond to perfusion with ABA in a concentration-dependent manner. The properties of the observed ABA accumulation in roots appear incompatible with the activity of known ABA transporters (AIT1, ABCG40). ABACUS reveals effects of external ABA on homeostasis, that is, ABA-triggered induction of ABA degradation, modification, or compartmentation. ABACUS can be used to study ABA responses in mutants and quantitatively monitor ABA translocation and regulation, and identify missing components. The sensor screening platform promises to enable rapid fine-tuning of the ABA sensors and engineering of plant and animal hormone sensors to advance our understanding of hormone signaling. DOI:http://dx.doi.org/10.7554/eLife.01741.001 Plants are able to respond to detrimental changes in their environment—when, for example, water becomes scarce or the soil becomes too salty—in ways that minimize stress and damage caused by these changes. Hormones are chemicals that trigger the plant’s response under these circumstances. Abscisic acid is the hormone that regulates how plants respond to drought and salt stress, and also controls growth and development. In the past, it was possible to measure the average level of this hormone in a given tissue, but not the level in individual cells in a living plant, nor in specific compartments within a cell. Moreover, it was difficult to follow directly how abscisic acid moved between the plant cells, tissues or organs. Now, Jones et al. (and independently Waadt et al.) have developed tools that can measure the levels of abscisic acid within defined compartments of individual cells in living plants and in real time. The plants were genetically engineered to produce sensor proteins with two properties: they can bind to abscisic acid in a reversible manner, and they contain two ‘reporters’ that fluoresce at different wavelengths. Shining light onto the plant at a specific wavelength that is only absorbed by one of the reporters causes both of the reporters on the sensor proteins to fluoresce. However, the two reporters fluoresce differently when the sensor binds to abscisic acid. Specifically, one reporter fluoresces more and the other less. Hence, measuring the ratio of these two wavelengths in the light that is given off by the sensor proteins can be used as a measure of the concentration of abscisic acid in a plant cell. Jones et al. used a high-throughput platform to engineer five sensor proteins that detect abscisic acid over a wide range of concentrations. Using these ‘ABACUS’ sensors in living plants could track the uptake of abscisic acid into root cells, and revealed that the concentration of the hormone inside the cell stayed below the levels provided on the outside. Since known abscisic acid-transporters are capable of raising the hormone concentration inside a cell above that provided on the outside, abscisic acid transport into plant roots may occur via as-yet-undiscovered transporter proteins. Jones et al. also show that root cells rapidly eliminate abscisic acid, and that adding extra abscisic acid to the roots increases the rate of elimination within minutes. Plants were also engineered to target the sensor proteins specifically to the cell nucleus. In the future, targeting these sensors to the cell wall should allow tracking of the cell-to-cell movement of this hormone. Further aims include using ABACUS to track abscisic acid in plants undergoing stress, and to use the high-throughput platform to develop new sensors to track other hormones in living organisms (including animals). DOI:http://dx.doi.org/10.7554/eLife.01741.002
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Affiliation(s)
- Alexander M Jones
- Department of Plant Biology, Carnegie Institution for Science, Stanford, United States
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41
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Tohge T, Fernie AR. Lignin, mitochondrial family, and photorespiratory transporter classification as case studies in using co-expression, co-response, and protein locations to aid in identifying transport functions. FRONTIERS IN PLANT SCIENCE 2014; 5:75. [PMID: 24672529 PMCID: PMC3955873 DOI: 10.3389/fpls.2014.00075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
Whole genome sequencing and the relative ease of transcript profiling have facilitated the collection and data warehousing of immense quantities of expression data. However, a substantial proportion of genes are not yet functionally annotated a problem which is particularly acute for transport proteins. In Arabidopsis, for example, only a minor fraction of the estimated 700 intracellular transporters have been identified at the molecular genetic level. Furthermore it is only within the last couple of years that critical genes such as those encoding the final transport step required for the long distance transport of sucrose and the first transporter of the core photorespiratory pathway have been identified. Here we will describe how transcriptional coordination between genes of known function and non-annotated genes allows the identification of putative transporters on the premise that such co-expressed genes tend to be functionally related. We will additionally extend this to include the expansion of this approach to include phenotypic information from other levels of cellular organization such as proteomic and metabolomic data and provide case studies wherein this approach has successfully been used to fill knowledge gaps in important metabolic pathways and physiological processes.
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Affiliation(s)
- Takayuki Tohge
- *Correspondence: Takayuki Tohge, Department 1 (Willmitzer), Central Metabolism, Max Planck Institute for Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany e-mail:
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Ho CH, Frommer WB. Fluorescent sensors for activity and regulation of the nitrate transceptor CHL1/NRT1.1 and oligopeptide transporters. eLife 2014; 3:e01917. [PMID: 24623305 PMCID: PMC3950950 DOI: 10.7554/elife.01917] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
To monitor nitrate and peptide transport activity in vivo, we converted the dual-affinity nitrate transceptor CHL1/NRT1.1/NPF6.3 and four related oligopeptide transporters PTR1, 2, 4, and 5 into fluorescence activity sensors (NiTrac1, PepTrac). Substrate addition to yeast expressing transporter fusions with yellow fluorescent protein and mCerulean triggered substrate-dependent donor quenching or resonance energy transfer. Fluorescence changes were nitrate/peptide-specific, respectively. Like CHL1, NiTrac1 had biphasic kinetics. Mutation of T101A eliminated high-affinity transport and blocked the fluorescence response to low nitrate. NiTrac was used for characterizing side chains considered important for substrate interaction, proton coupling, and regulation. We observed a striking correlation between transport activity and sensor output. Coexpression of NiTrac with known calcineurin-like proteins (CBL1, 9; CIPK23) and candidates identified in an interactome screen (CBL1, KT2, WNKinase 8) blocked NiTrac1 responses, demonstrating the suitability for in vivo analysis of activity and regulation. The new technology is applicable in plant and medical research. DOI:http://dx.doi.org/10.7554/eLife.01917.001 About 1% of global energy output is used to produce nitrogen-enriched fertiliser to improve crop yields, but much of this energy is wasted because plants absorb only a fraction of the nitrogen that is applied as fertiliser. Even worse, the excess nitrogen leaches into water sources, poisoning the environment and causing health problems. However, to date, most efforts to increase the efficiency of nitrogen uptake in plants have been unsuccessful. The key to improving the uptake efficiency of a nutrient is to identify obstacles in its journey from the soil to cells inside the plant. The first obstacle that nitrate ions encounter is the membrane of the cells on the surface of the roots of the plant. Many researchers believe that it would be possible to increase the amount of nitrogen absorbed by the plant if more was known about the ways that plants control how nitrate ions and other chemicals enter cells. The cell membrane contains gated pores called transporters that allow particular molecules to pass through it. Although the transporters responsible for the uptake of nitrate ions, peptides, and ammonium ions (the main nitrogen compounds that plants acquire) have been identified, current experimental techniques cannot determine when and where a specific transporter is active within a living plant. This makes it difficult to know where to target modifications and to determine how effective they have been at each step. The nitrate transporter also acts as an antenna that measures nitrate concentration to ensure it is used optimally in the plant, but current techniques cannot show how this actually works. Now, Ho and Frommer have exploited the fact that a transporter changes shape as it does its job to create sensors that can track the movement of nitrate and peptides through the cell membrane. By using fluorescent proteins to monitor how the shape of the transporter changes, Ho and Frommer were able to measure how structural mutations and regulatory proteins influenced the movement of nitrate and peptides through the membrane. For efficiency, all of this work was performed in yeast cells. The next goal is to use the technique in plants to uncover how they adjust to changes in nutrient levels in the soil. DOI:http://dx.doi.org/10.7554/eLife.01917.002
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Affiliation(s)
- Cheng-Hsun Ho
- Department of Plant Biology, Carnegie Institution for Science, Stanford, United States
| | - Wolf B Frommer
- Department of Plant Biology, Carnegie Institution for Science, Stanford, United States
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De Michele R, Carimi F, Frommer WB. Mitochondrial biosensors. Int J Biochem Cell Biol 2014; 48:39-44. [PMID: 24397954 DOI: 10.1016/j.biocel.2013.12.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/26/2013] [Indexed: 10/25/2022]
Abstract
Biosensors offer an innovative tool for measuring the dynamics of a wide range of metabolites in living organisms. Biosensors are genetically encoded, and thus can be specifically targeted to specific compartments of organelles by fusion to proteins or targeting sequences. Mitochondria are central to eukaryotic cell metabolism and present a complex structure with multiple compartments. Over the past decade, genetically encoded sensors for molecules involved in energy production, reactive oxygen species and secondary messengers have helped to unravel key aspects of mitochondrial physiology. To date, sensors for ATP, NADH, pH, hydrogen peroxide, superoxide anion, redox state, cAMP, calcium and zinc have been used in the matrix, intermembrane space and in the outer membrane region of mitochondria of animal and plant cells. This review summarizes the different types of sensors employed in mitochondria and their main limits and advantages, and it provides an outlook for the future application of biosensor technology in studying mitochondrial biology.
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Affiliation(s)
- Roberto De Michele
- Institute of Biosciences and Bioresources, National Research Council of Italy (CNR-IBBR), Corso Calatafimi 414, 90129 Palermo, Italy.
| | - Francesco Carimi
- Institute of Biosciences and Bioresources, National Research Council of Italy (CNR-IBBR), Corso Calatafimi 414, 90129 Palermo, Italy
| | - Wolf B Frommer
- Department of Plant Biology, Carnegie Institute for Science, 260 Panama Street, Stanford, CA 94305, USA
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Ammonium transport sensors. Nat Methods 2013. [DOI: 10.1038/nmeth.2621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wang Y, Javitch JA. Getting to grips with ammonium. eLife 2013; 2:e01029. [PMID: 23840933 PMCID: PMC3699818 DOI: 10.7554/elife.01029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A fluorescent sensor that can monitor levels of extracellular ammonium has been made by using a fused green fluorescent protein to detect conformational changes in ammonium transport proteins.
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Affiliation(s)
- Yi Wang
- is in the Department of Psychiatry and the Center for Molecular Recognition , Columbia University , New York , United States , and the Division of Molecular Therapeutics , New York State Psychiatric Institute , New York , United States
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