1st Edition
Membrane Transport in Plants Annual Plant Reviews, Volume Fifteen
Research in to membrane transport has advanced rapidly in recent years, following the availability of new biophysical techniques, the integration of structural and molecular approaches, and developments in molecular genomics. With an expanding population, agricultural production is pushed increasingly into marginal areas, promoting interest in the genetic engineering of crop species to cope with these conditions. Membrane Transport in Plants provides on overview of our current understanding of plant membrane transport in the light of recent developments. The volume is directed at researchers and professionals in plant cell biology, biochemistry and physiology.
List of Contributors
Preface
Concepts and techniques in plant membrane physiology
Michael R. Blatt
Introduction
Plant membrane transport
Intracellular recording and the voltage clamp
Patch clamp
Separating and analsying membrane currents
Steady-state current
Current relaxations and ion channel gating
Analyzing single-channel current
Microinjection and perfusion
Radiotracer flux analysis
Conclusion
Acknowledgements
References
Electrophysiology equipment and software
Adrian Hills and Vadim Volkov
Introduction
Voltage clamp protocols
Voltage stepping protocols
Voltage ramp protocols
‘Tail current’ protocols
Time-variant protocols
Extended single-channel recording
Equipment and hardware
The working environment
Capillaries and micropipettes
Electronics
Data acquisition and control boards
Scientific Solutions ‘LabMaster’ Boards
Instrutech Corporation’s ITC Interfaces
Axon Instruments’ DigiData Systems
National Instruments Cards
Data Translation
Choosing a computer
Computer software
Basic requirements
Signal conditioning
Data analysis tools
IV analysis
Curve titting
Single-channel analysis
Data export
Commercially available software
Pulse+PulseFit (HEKA Elektronik GmbH)
The pClamp Suite (Axon Instruments)
Other commercial packages
Whole Cell Patch
Henry II’s EP Suite
Overview
The Henry II application
The protocol editor
Run-time monitoring and analysis
Post-acquisition data analysis
The Vicar V2 virtual chart recorder
Noise reduction and removal with N-Pro V2
The Pandora! application
The Y-Science ADC/DAC board drivers
References
Structure, function and regulation of primary H+ and Ca2+ pumps
Rosa L. López-Marqués, Morten Schiøtt, Mia Kyed Jakobsen and Michael G. Palmgren
Pumps in plants
Proton pumps in plant cells
Plasma membrane H+ -ATPase
Physiological role
Genetics
Structure and mechanism
Isoforms and expression in the plant
Regulation
V-ATPase
Physiological role
Genetics
Structure and mechanism
Isoforms and expression in the plant
Regulation
Vacuolar pyrophosphate
Physiological role
Structure and mechanism
Isoforms and expression in the plant
Regulation
Calcium pumps in plant cells
Calcium in plant cells
Ca+ -ATPase (P2 ATPases)
Physiological role
Genetics
Structure and mechanism
Isoforms and expression in the plant
Regulation
Other plant cation pumps
Acknowledgments
References
Ion-coupled transport of inorganic solutes
Malcom J. Hawkesford and Anthony J. Miller
Introduction
Ion gradients and ion-coupled transport mechanisms
Thermodynamics of ion-coupled transport
Determining the feasibility of co-transport mechanisms
Functions and relationships to physiology
Targeting and membrane location
Transporter expression and nutrient availability
Types of ion-coupled transporter
Nitrate
Physiology of nitrate transport mechanisms
Nitrate transporter gene families
Regulation of expression
Function in the root
Function in the leaf
Sulphate
The sulphate transporter gene family
Functional characterization
Regulation
Ammonium
NH4+uptake gene family
Function in the root
Function in the leaf
Energetic costs of transport
Nitrate and sulphate efflux
Ammonium efflux
Conclusions and future research
Gene families and functional diversity
Homeostasis of cell nutrients and nutrient sensors
Conclusions
Acknowledgements
References
Functional analysis of proton-coupled sucrose transport
Daniel R. Bush
Introduction
Defining basic properties of transport
Intact tissues
Membrane vesicles
Sucrose sensing
Heterologous expression systems
Sucrose transport in plant growth and development
Patterns of gene expression
Antisense expression and gene knockouts in transgenic plants
References
Voltage-gated ion channels
Ingo Dreyer, Bernd Müller-Röber and Barabara Köhler
Introduction
Voltage gating from a mechanistic point of view
Static- steady-state equilibrium
Kinetic- relaxation into an equilibrium
Comparison of the model with the in vivo situation
Voltage-gated ion channels uncovered in plants and their involvements in physiological processes
Plasma membrane potassium channels
Hyperpolarisation-activated K+ channels –Kin channels
Depolarisation-activated K+ channels –Kout channels
Weakly rectifying K+ channels –Kweak channels
Vacuolar potassium channels
Slow-activating vacuolar channel
Fast-activating vacuolar channel
Vacuolar K+ channels
Plasma membrane calcium channels
Hyperpolarisation-activated Ca2+ channels
Depolarisation-activated Ca2+ channels
Vacuolar calcium release channels
Calcium channels in the endoplasmatic reticulum
Plasma membrane anion channels
Depolarization-activated anion channels
Inward-rectifying anion channels
Vacuolar anion channels
Gating modifiers
Phosphorylation
Nitrosylation and other redox reactions
Calcium ions
Protons
Cytosolic pH changes
Extracellular/luminal pH changes
Potassium ions
Anions
Phytohormones
Auxins
Abscisic acid
Lipids and their hydrolysis products
Proteins and peptides
G-proteins
14-3-3 Proteins
Calmodulin
Outlook- voltage ion channels in ‘Systems Biology’
References
Ligand-gated ion channels
Frans Maathuis
Introduction
Acetylcholine receptors, the archetypal ligand-gated ion channels
Techniques to study ligand-gated channels
Plant ligand-gated ion channels
Ca2+ release channels from endomembranes
Ip3-gated channels
cADPR-gated channels
NAADP-gated channels
Non-selective ligand-gated ion channels
Glutamate receptors
Cyclic-nucleotide-gated channels
Concluding remarks
References
Aquaporins in plants
Clare Vander Willigen, Lionel Verdoucq, Yann Boursiac and Christophe Maurel
Introduction
Water transport measurements: principles and methods
Theory
Stopped-flow techniques
Swelling of isolated cells, protoplasts and vacuoles
The pressure probe technique
Water transport measurements on excised organs
Nuclear magnetic resonance techniques
Aquaporins at the level of molecules, cells and tissues
Classification of plant aquaporins
Molecular level: a variety of selectivity profiles
Transport selectivity
Aquaporin structure and molecular basis of aquaporin selectivity
Significance of CO2 transport
Cell level: subcellular targeting
Pattern of aquaporin expression within the cell
Role of aquaporins in cell osmoregulation
Tissue level: the role of aquaporins in root water uptake
Cell-specific expression patterns
Role of cell membranes and aquaporins in water uptake
Mechanisms of regulation
Levels of regulation
Regulation of gene expression
Protein translation and degradation
Protein targeting
Molecular mechanisms of aquaporin gating
Regulation by phosphorylation
Regulation by protons
Conclusion
References
Ca2+ and pH as integrating signals in transport control
Tatiana N. Bibikova, Sarah M. Assmann and Simon Gilroy
Introduction
Transport and the control of development
Plant and algal transporters and tip-growth control
Tip growth shows oscillations in fluxes and growth
How are local Ca2+ gradients formed?
G-proteins regulating ion fluxes at the apex
Regulation of H+ fluxes
Transport and the reversible control of cell volume
The mechanistic basis of reversible cell volume change
Calcium and volume change in motor cells
Ca2+, secretion and the cytoskeleton
How are Ca2+ oscillations generated?
G-proteins regulating signaling in guard cells
Regulation of H+ fluxes
Roles of extracellular Ca2+ and pH in wall structure/activity of guard cells and pulvinar cells
Conclusions and perspectives
Acknowledgements
References
Vesicle traffic and plasma membrane transport
Annette C. Hurst, Gerhard Thiel and Ulrike Homann
Introduction
Membrane turnover in plants
Turnover of membrane proteins
Cycling and redistribution of PIN
Cycling of K+ channels in guard cells
Auxin-induced channel expression in elongating cells
Parallels to mechanisms in animal cells
Regulatory mechanisms in membrane trafficking and their implications for activity of ion transport proteins
ER export as control step in surface expression of ion channels
Ca2+ and exocytosis
Membrane tension and exo- and endocytosis
SNARE proteins and their possible role in ion channel trafficking and gating
Acknowledgements
References
Potassium nutrition and salt stress
Anna Amtmann, Patrick Armengaud and Vadim Volkov
The physiology of potassium nutrition and salt stress
The physiology of potassium nutrition
Roles of potassium in the plant
Symptoms of potassium starvation and impact on agriculture
Potassium mutants
Potassium homeostasis
The physiology of salt stress
The problem with salt
Sodium toxicity
Sodium mutants
Sodium homeostasis
Setting the scene for K+ and Na+ transport
Driving forces for K+ and Na + movement across membranes
Tissues and membranes involved in K+ and Na+ transport
Functional genomics of K+ and Na+ transport: linking experimental evidence
Function types of transporters involved in K+ homeostasis and salt stress
Transport pathways for K+ and Na+
Voltage-dependent channels
Voltage-independent channels
Genes encoding cation-selective channels
Active transport of K+ and Na+
The KUP/HAK/KYA family
HKT
Antiporter genes
Other cation transporters
Providing the driving force for K+ and Na+ transport: proton pumps
Other transporters involved in K+ homeostasis and salt stress
ABC transporters
Aquaporins
Regulation and integration of K+ and Na+ transport
Perception of K+ and Na+
Intracellular signaling of cation stress
Cytoplasmic Ca2+, kinases and phosphatases
Cyclic nucleotides
Other regulators of ion transport
Hormonal control of ion homeostasis
Abscisic acid
Jasmonic acid and polyamines
Future prospects
Technologies
Model plants
Concluding remarks
References
Membrane transport and soil bioremediation
Susan Rosser and Peter Dominy
Introduction
Phytostabilisation
Root exudation
Enrichment of microbial degraders
Enhancement of microbial biodegradation activity
Mechanisms of exudation
Phytoextraction
Uptake of heavy metals from the rhizosphere
Formation and transport of intracellular chelates
Transport to the shoot
Distribution and compartmentation in the shoot
Discussion
References
Index
Biography
Michael R. Blatt
