Plant Aquaporins

Aquaporins are channel proteins that facilitate the diffusion of water and small uncharged solutes across cellular membranes. Plant aquaporins form a large family of highly divergent proteins that are involved in many different physiological processes. This book will summarize the recent advances regarding plant aquaporins, their phylogeny, structure, substrate specificity, mechanisms of regulation and roles in various important physiological processes related to the control of water flow and small solute distribution at the cell, tissue and plant level in an ever-changing environment.

Aquaporins (AQPs), a class of integral membrane proteins, form channels facilitating movement of water and many other solutes. In solute transport systems of all living organisms including plants, animals and fungi, AQPs play a vital role. Plants contain a much higher number of AQP genes compared to animals, the likely consequence of genome duplication events and higher ploidy levels. As a result of duplication and subsequent diversification, plant AQPs have evolved several subfamilies with very diverse functions. Plant AQPs are highly selective for specific solutes because of their unique structural features. For instance, ar/R selectivity filters and NPA domains have been found to be key elements in governing solute permeability through the AQP channels. Combination of conserved motifs and specific amino acids influencing pore morphology appears to regulate the permeability of specific solutes such as water, urea, CO2, H2O2, boric acid, silicic acid and many more. The discovery of novel AQPs has been accelerated over the last few years with the increasing availability of genomic and transcriptomic data. The expanding number of well characterised AQPs provides opportunities to understand factors influencing water transport, nutritional uptake, and elemental balance. Homology-based search tools and phylogenetic analyses offer efficient strategies for AQP identification. Subsequent characterization can be based on different approaches involving proteomics, genomics, and transcriptomic tools. The combination of these technological advances make it possible to efficiently study the inter-dependency of AQPs, regulation through phosphorylation and reversible phosphorylation, networking with other transporters, structural features, pH gating systems, trafficking and degradation. Several studies have supported the role of AQPs in differential phenotypic responses to abiotic and biotic stress in plants. Crop improvement programs aiming for the development of cultivars with higher tolerance against stresses like drought, flooding, salinity and many biotic diseases, can explore and exploit the finely tuned AQP-regulated transport system. For instance, a promising approach in crop breeding programs is the utilization of genetic variation in AQPs for the development of stress tolerant cultivars. Similarly, transgenic and mutagenesis approaches provide an opportunity to better understand the AQP transport system with subsequent applications for the development of climate-smart drought-tolerant cultivars. The contributions to this Frontiers in Plant Science Research Topic have highlighted the evolution and phylogenetic distribution of AQPs in several plant species. Numerous aspects of regulation that seek to explain AQP-mediated transport system have been addressed. These contributions will help to improve our understanding of AQPs and their role in important physiological aspects and will bring AQP research closer to practical applications.

This book provides up-to-date coverage at an advanced level of a range of topics in the biochemistry and molecular biology of plant hormones, with particular emphasis on biosynthesis, metabolism and mechanisms of action. Each contribution is written by acknowledged experts in the field, providing definitive coverage of the field. No other modern book covers this subject matter at such an advanced level so comprehensively. It will be invaluable to university libraries and scientists in the plant biotechnology industries.

Aquaporins summarizes the present knowledge in this expanding field of research, starting with the structural analysis of water channel proteins. Subsequent chapters begin with mammalian aquaporins, examining physiology and pathophysiology, analysis of knock-out model animals, and the regulation of aquaporin function. Also covered is the distribution and regulation of aquaporins in plants and the function of water and glycerol channels in microbial systems. Comprehensive treatment of a topical research field Authored by world leaders in the field Covers structural biology and physiology Covers different experimental and biological systems Chapters on plant and microbial systems Extensive treatment of mammalian physiology and pathophysiology Structural analysis excellently illustrated

In plant cells, the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. Transactions at the plasma membrane include uptake of water and essential mineral nutrients, gas exchange, movement of metabolites, transport and perception of signaling molecules, and initial responses to external biota. Selective transporters control the rates and direction of small molecule movement across the membrane barrier and manipulate the turgor that maintains plant form and drives plant cell expansion. The plasma membrane provides an environment in which molecular and macromolecular interactions are enhanced by the clustering of proteins in oligimeric complexes for more efficient retention of biosynthetic intermediates, and by the anchoring of protein complexes to promote regulatory interactions. The coupling of signal perception at the membrane surface with intracellular second messengers also involves transduction across the plasma membrane. Finally, the generation and ordering of the external cell walls involves processes mediated at the plant cell surface by the plasma membrane. This volume is divided into three sections. The first section describes the basic mechanisms that regulate all plasma membrane functions. The second describes plasma membrane transport activity. The final section of the book describes signaling interactions at the plasma membrane. These topics are given a unique treatment in this volume, as the discussions are restricted to the plasma membrane itself as much as possible. A more complete knowledge of the plasma membrane’s structure and function is essential to current efforts to increase the sustainability of agricultural production of food, fiber, and fuel crops.

A guide to the chemical agents that protect plants from various environmental stressors Protective Chemical Agents in the Amelioration of Plant Abiotic Stress offers a guide to the diverse chemical agents that have the potential to mitigate different forms of abiotic stresses in plants. Edited by two experts on the topic, the book explores the role of novel chemicals and shows how using such unique chemical agents can tackle the oxidative damages caused by environmental stresses. Exogenous application of different chemical agents or chemical priming of seeds presents opportunities for crop stress management. The use of chemical compounds as protective agents has been found to improve plant tolerance significantly in various crop and non-crop species against a range of different individually applied abiotic stresses by regulating the endogenous levels of the protective agents within plants. This important book: Explores the efficacy of various chemical agents to eliminate abiotic stress Offers a groundbreaking look at the topic and reviews the most recent advances in the field Includes information from noted authorities on the subject Promises to benefit agriculture under stress conditions at the ground level Written for researchers, academicians, and scientists, Protective Chemical Agents in the Amelioration of Plant Abiotic Stress details the wide range of protective chemical agents, their applications, and their intricate biochemical and molecular mechanism of action within the plant systems during adverse situations.

Since the discovery of Aquaporin-1 (AQP1) as a water channel, many studies have revealed the importance of aquaporins in mammalian physiology and pathophysiology as well as plant and microbial biology. The studies have also shown aquaporins as potential drug targets and targets for improving crop properties. Written by an international group of contributors at the forefront of the field, Aquaporins in Health and Disease: New Molecular Targets for Drug Discovery presents the latest research advances in aquaporins and other major intrinsic protein (MIP) channels. The first section of the book describes the general concepts of aquaporin channel function, genomic research, structure-function analysis of aquaporins and glycerol facilitators, and regulation by gating and trafficking, including yeast aquaporin regulation and function. The second section discusses the physiological and pathophysiological roles of aquaporins in humans and microbes. The final section covers the development of inhibitors of aquaporin function. The book’s epilogue offers future perspectives and directions, mainly in the area of aquaporin-based diagnostics and therapeutics. Stimulating future research on this important protein family, this book facilitates a paradigm shift in the understanding and roles of aquaporin membrane proteins in all biological settings. It encourages scientists to develop novel approaches for the treatment of human diseases based on aquaporin function or dysfunction.

This edited book stands as a one place knowledge hub for plant metal(loid) transporters. The book comprehensively covers holistic aspect of metal(loid) transporters involved in uptake and translocation of essential as well as toxic metal(loid)s. Essential and beneficial metal(loid)s are required in every biological process for normal plant growth and development, however in excess they are toxic. There are toxic metal(loid)s also whose accumulation in plants interferes with normal cellular functioning and hampers growth of plants. Hence, metal(loid) uptake and accumulation in plants is a highly regulated phenomenon involving the role of several transporters, enzymes, metabolites, transcription factors and post translational modifications. The book contains chapters from the experts and the contents of the book are presented in simple language and represented through beautiful and scientifically informative figures and tables. This book is of interest to teachers, researchers, doctoral and graduate students working in the area of plant physiology, environmental biotechnology, plant biotechnology metal(loid) stress, phytoremediation and crop biofortification.