Cytokinins As Central Regulators Of Plant Growth And Development

Plant development, growth and metabolism are highly complex processes requiring the precise fine-tuning of the different molecules involved. Plant growth regulators, also known as plant hormones or phytohormones, are signaling molecules that coordinate these processes, both locally and over greater distance, thereby influencing the growth, development and differentiation of cells, tissues and organs. By compiling open access research papers, the present books reviews the current knowledge on the main plant growth regulators: ABA, auxins, cytokinins, gibberellins, ethylene, brassinosteroids, jasmonic acid, nitric oxide, salicylic acid and strigolactones. In Chapter number 1, the editor presents a detailed overview of strigolactones, the plant growth regulators most recently identified, covering their structure and biosynthesis, signaling and biological functions. The role of ABCG-type ABC transporters in the transport of ABA, cytokinins and strigolactones is discussed in Chapter 2. In Chapter 3, the signaling process of ABA, as well as the role of the PYR/PYL/RCAR receptors, the PP2C phosphatases and the SnRK2 kinases in it, is briefly reviewed. While Chapter 4 exposes the well-known role of this phytohormone in abiotic stress signaling, Chapter 5 describes its function in regulating root length and architecture. In Chapter 6, the response to auxins through the pathways involving TIR1/AFB1, SKP2A, SAUR proteins, IBR5 and MPK12, and ABP1 and TMK1 is discussed. The different families of auxin transporters, as well as their role in monocot development, are reviewed in Chapter 7. Chapter 8 describes how auxin signaling, homeostasis, cross-talk with other phytohormones and interaction with environmental factors controls root hair growth. The homeostasis, signaling and cross-talks of brassinosteroids are described in Chapter 9, while Chapter 10 reviews the biological functions of this phytohormone in rice. Cytokinin signaling and transport are respectively described in Chapters 11 and 12, being a brief overview of the role of this hormone in regulating the architecture of inflorescences presented in Chapter 13. The interaction of ethylene and light signaling to promote hypocotyl growth is described in Chapter 14, while the biological functions of this phytohormone concerning seed dormancy.

Plant hormones have pivotal roles in the regulation of plant growth, development, and reproduction. Their signaling pathways are interconnected in a complex network, which provides plants with an enormous regulatory potential to rapidly adapt to their environment and to utilize their limited resources for growth and survival in a cost-efficient manner. Auxin is a hormone molecule whose activity levels are most important for its regulatory roles during plant cell, organ, and tissue development. Therefore, the precise regulation of auxin levels is an essential mechanism to fine-tune the activity of this powerful hormone during plant growth and development. Likewise, cytokinins exhibit a wide range of physiological functions, including regulation of shoot and root apical meristems, stimulation of branching, vascular development, chloroplast differentiation, stabilization of the structure and function of the photosynthetic machinery, delay of senescence, stomata opening, and elevation of the sink strength and nutritional signaling. Moreover, gibberellins also regulate many aspects of plant growth and development including seed germination, stem elongation, leaf expansion, and flower and fruit development. The broad implication of gibberellins in plant development is strictly associated with tight regulation of their metabolism by multiple environmental and endogenous factors, ranging from light and temperature to other hormones including feedback control. Understanding the significant roles of these phytohormones in plant biology, the current subject has attracted the attention of scientists from across the globe. This comprehensive volume “Auxins, Cytokinins and Gibberellins Signaling in Plants” highlights the various prospects involved in the current scenario. The book comprises the chapters from diverse areas dealing with biotechnology, molecular biology, proteomics, genomics, metabolomics, etc.

Cytokinins are hormones involved in all aspects of plant growth and development and are essential for in vitro manipulation of plant cells and tissues. Much information has been gathered regarding the chemistry and biology of cytokinins, while recent studies have focused on the genetics and cytokinin-related genes. However, other than proceedings of symposia, no single volume on cytokinins has been written. This book is the first of its kind, homing in on the key subject areas of cytokinin-chemistry, biosynthesis, metabolism, activity, function, genetics, and analyses. These areas are comprehensively reviewed in individual chapters by experts currently active in the field. In addition, a personal history on the discovery of cytokinin is presented by Professor Folke Skoog. This volume summarizes previous findings and identifies future research directions.

Plant Hormones: Biosynthesis and Mechanisms of Action is based on research funded by the Chinese government’s National Natural Science Foundation of China (NSFC). This book brings a fresh understanding of hormone biology, particularly molecular mechanisms driving plant hormone actions. With growing understanding of hormone biology comes new outlooks on how mankind values and utilizes the built-in potential of plants for improvement of crops in an environmentally friendly and sustainable manner. This book is a comprehensive description of all major plant hormones: how they are synthesized and catabolized; how they are perceived by plant cells; how they trigger signal transduction; how they regulate gene expression; how they regulate plant growth, development and defense responses; and how we measure plant hormones. This is an exciting time for researchers interested in plant hormones. Plants rely on a diverse set of small molecule hormones to regulate every aspect of their biological processes including development, growth, and adaptation. Since the discovery of the first plant hormone auxin, hormones have always been the frontiers of plant biology. Although the physiological functions of most plant hormones have been studied for decades, the last 15 to 20 years have seen a dramatic progress in our understanding of the molecular mechanisms of hormone actions. The publication of the whole genome sequences of the model systems of Arabidopsis and rice, together with the advent of multidisciplinary approaches has opened the door to successful experimentation on plant hormone actions. Offers a comprehensive description of all major plant hormones including the recently discovered strigolactones and several peptide hormones Contains a chapter describing how plant hormones regulate stem cells Offers a fresh understanding of hormone biology, particularly molecular mechanisms driving plant hormone actions Discusses the built-in potential of plants for improvement of crops in an environmentally friendly and sustainable manner

Hormone Action in Plant Development - A Critical Appraisal documents the proceedings of the Tenth Long Ashton Symposium, September 1986. The symposium was convened to assess the evidence for and against the view that plant hormones are endogenous regulators of plant development. The meeting also aimed to focus on and assess promising strategies for future research. The symposium opened with the Douglas Wills Lecture, given by Professor Carl Leopold. In many respects, progress in research on animal hormones seems greater than in the plant sciences and there may well be merit in following progress in animal hormone research as suggested by Professor Leopold. The symposium was comprised of four sessions. The introductory session considered the coordinating role of hormones in plant growth and development, and focused on hormone action at the molecular level, including their binding to receptors and their control of gene expression. The next two sessions embraced contributions on the experimental manipulation of development by genetic (notably by biochemical mutants), chemical (for example, with gibberellin/biosynthesis inhibitors), and environmental (including drought stress) means. All these approaches consolidated the central importance of hormones in plant growth. In the final session, three speakers suggested some promising avenues for future research into the physiology, biochemistry, and molecular biology of plant hormones.

The Role of Plant Growth Regulators and Phytohormones in Overcoming Environmental Stress is a comprehensive resource on all major PGRs. These include auxins, cytokinins, jasmonates, polyammines, plant growth promoting rhizobacteria (PGPR), and more. In the last two decades, researchers have explored a lot about the roles of plant growth regulators (PGRs) in boosting the resistance of plants under stress conditions. These PGRs acts as stimulators for various physiological processes by regulating key cell signaling pathways. This title is an essential read for any scientist wanting to understand the latest advances in combatting abiotic stresses using plant growth regulators. In the present era, plants are facing a lot of challenges during their lifecycle, including growth declines due to abiotic stress. The main abiotic stresses threatening plants are water scarcity, salinity, extreme temperatures, heavy metals and pesticides. These stresses directly or indirectly cause toxicity to plants, causing hindrance to their growth and development, and ultimately reduce plant productivity. Provides the latest research on all major Plant Growth Regulators (PGRs) Focuses on the mechanistic approaches of the physiological and molecular actions of PGRs Highlights crosstalk between PGRs and phytohormones