Ion Transport at the Plant Plasma Membrane

Abstract

Membrane transport plays a fundamental role in virtually every aspect of homeostasis, signalling, growth and development in plants. At the plasma membrane, the boundary with the outside world, ion and solute fluxes underpin inorganic mineral nutrient uptake, they trigger rapid changes in second messengers such as cytosolic‐free Ca 2+ concentrations and they power the osmotic gradients that drive cell expansion, to name just a few roles. Our understanding of the transporters – the ion pumps that generate an H + electrochemical driving force, H + ion‐coupled symport and antiport systems and ion channels – now, more than ever, builds on developments in molecular genetics, genomics, protein chemistry and crystallography to gain insights into the fine structure and mechanics of these remarkable enzymes. Even so, it is the interface with the biophysical detail of ion transport that drives scientific enquiry in the field and will continue to be essential in informing both the most fundamental research as well as efforts to apply the knowledge gained in resolving some of the dilemmas that face society today. Key Concepts Study of ion transport is the key for our understanding of mineral nutrition in plants. Ion transporters and their biophysical properties form the basis for understanding of the membrane potentials. Plasma membrane H + ‐ATPase of plants and the Na + /K + ‐ATPase of animals are both members of the P‐type membrane ATPase superfamily. The transport of many solutes is coupled by H + across plasma membrane of plant cells. Ion channels carry much larger current than pumps and cotransporters on a unit protein basis. Membrane vesicle traffic regulates ion transport by controlling the population and availability of transporters at the membrane and, in some cases, by direct binding with ion transporters. Plasma membrane ion transporters have coevolved with the evolution of land plants.

Does Molecular and Structural Evolution Shape the Speedy Grass Stomata?

“…In addition to stomatal morphological structure and development, many genetic and environmental factors are involved in stomatal response (Lawson and Vialet-Chabrand, 2018). Light (Shimazaki et al, 2007;Babla et al, 2019), CO 2 (Engineer et al, 2014;Kolbe et al, 2018), GC membrane transport (Blatt, 2000;Hanba et al, 2004;Sade et al, 2010;Perrone et al, 2012;Lawson and Blatt, 2014), abscisic acid (ABA), reactive oxygen species (ROS), nitric oxide (NO), Ca 2+ , and pH signaling (Yang et al, 2005;Bussis et al, 2006;Hettenhausen et al, 2012;Chen et al, 2016;Wang et al, 2018), and mesophyll photosynthesis (McAusland et al, 2016;Lawson and Vialet-Chabrand, 2018) all determine the speed and magnitude of stomatal movement. Moreover, many environmental stimuli regulate stomatal opening and closure via coordinated cell signaling and membrane transport activities (Kollist et al, 2014).…”

Optimized Protocol for OnGuard2 Software in Studying Guard Cell Membrane Transport and Stomatal Physiology

“…In light, H + -ATPase was activated to hyperpolarization of the plasma membrane, allowing K + uptake through inward-rectifying K + channels that open stomata (Jezek and Blatt, 2017;Wang et al, 2018). Overexpression of H + -ATPase had a significant effect on light induced stomatal opening and enhance plant growth in Arabidopsis (Wang et al, 2014b).…”

“…In plants, a complex intracellular signaling network regulates ionic fluxes-mainly K + , Cl − , and malate-across both plasma membrane and tonoplast, which adjusts the osmotic load and turgor pressure of guard cell that drive the opening and closing of stomata (Blatt, 2000;Hetherington, 2001;Schroeder et al, 2001). Our deep knowledge of this network has made guard cells one of the best-known models in plant cell biology for studying membrane transport, signaling, and ion homeostasis (Willmer and Fricker, 1995;Zhang et al, 2014;Murata et al, 2015;Eisenach and De Angeli, 2017;Jezek and Blatt, 2017;Wang et al, 2018;Sussmilch et al, 2019). However, predicting the full breadth of stomatal behavior from this body of knowledge is much more difficult than had been expected (Blatt et al, 2014).…”

Molecular Evolution and Interaction of Membrane Transport and Photoreception in Plants

“…Light is used as photosynthetic energy source as well as a vital regulator that can affect plant photomorphogenesis through the perception of the spectrum regulated by photoreceptors and potentially the downstream signaling component-membrane transporters. Membrane transport plays a central role virtually in all the aspects of plant ion and solute homeostasis and signaling transduction (Wang et al, 2018). Specialized plant membrane transporters are a promising target to increase crop yields, enhance produce quality, and improve resistance to abiotic and biotic stresses for the sustainable production of nutritious foods (Schroeder et al, 2013).…”

“…Comprehensive knowledge on plant membrane transporters and photoreceptors systems along with the increasing number of sequenced plant genomes have enabled the comparative genomic and evolutionary analysis of many gene families (Cai et al, 2017; Chen et al, 2017; Wang et al, 2018; Zhao et al, 2019). Discovering orthologous membrane transporters and photoreceptors and deciphering their key functions have also led to a growing interest in the manipulation of these genes to enhance crop yield and quality (Boccalandro et al, 2003; Ganesan et al, 2017).…”