The small phenolic compound salicylic acid (SA) is critical for plant defense against a broad spectrum of pathogens. SA is also involved in multi-layered defense responses, from pathogen-associated molecular pattern triggered basal defense, resistance gene-mediated defense, to systemic acquired resistance. Recent decades have witnessed tremendous progress towards our understanding of SA-mediated signaling networks. Many genes have been identified to have direct or indirect effect on SA biosynthesis or to regulate SA accumulation. Several SA receptors have been identified and characterization of these receptors has shed light on the mechanisms of SA-mediated defense signaling, which encompass chromosomal remodeling, DNA repair, epigenetics, to transcriptional reprogramming. Molecules from plant-associated microbes have been identified, which manipulate SA levels signaling. SA does not act alone. It engages in crosstalk with other signaling pathways, such as those mediated by other phytohormones, in an agonistic or antagonistic manner, depending on hormones and pathosystems. Besides affecting plant innate immunity, SA has also been implicated in other cellular processes, such as flowering time determination, lipid metabolism, circadian clock control, and abiotic stress responses, possibly contributing to the regulation of plant development. The multifaceted function of SA makes it critically important to further identify genes involved in SA signaling networks, understand their modes of action, and delineate interactions among the components of SA signaling networks. In addition, genetic manipulation of genes involved in SA signaling networks has also provided a promising approach to enhance disease resistance in economically important plants. This ebook collects articles in the research topic “Salicylic Acid Signaling Networks.” For this collection we solicited reviews, perspectives, and original research articles that highlight recent exciting progress on the understanding of molecular mechanisms underlying SA-mediated defense, SA-crosstalk with other pathways and how microbes impact these events.

Salicylic acid (SA) and methyl jasmonate (MJ) signaling is associated with phospholipids and the enzymes that metabolize them. However, despite the many studies conducted, the role of SA or MJ signalling via phospholipids in plant responses is not yet fully understood. The signaling pathways of SA and MJ have been evaluated in plant cell suspensions, and it was observed that these compounds regulate enzymatic activities to generate a rapid cellular response. This book discusses the immune responses induced by salicylic acid and jasmonic acids against plant parasites; the induction by SA of in vitro thermotolerance during thermotherapy; aalicylic acid, methyl jasmonate and phospholipid signaling in suspension cells; the self-association of salicylic acid derivatives in aqueous solutions studied by methods of absorption and fluorescence; and the role of exogenous salicylic acid applications for salt tolerance in tomato plants.

Demand for agricultural crops and nutritional requirement continues to escalate in response to increasing population. Also, climate change exerts adverse effects on agriculture crop productivity. Plant researchers have, therefore, focused to identify the scientific approaches that minimize the negative impacts of climate change on agricultural crops. Thus, it is the need of the hour to expedite the process for improving stress tolerance mechanisms in agricultural crops against various environmental factors, in order to fulfil the world’s food demand. Among the various applied approaches, the application of phytohormones has gained significant attention in inducing stress tolerance mechanisms. Jasmonates are phytohormones with ubiquitous distribution among plants and generally considered to modulate many physiological events in higher plants such as defence responses, flowering and senescence. Also, jasmonates mediate plant responses to many biotic and abiotic stresses by triggering a transcriptional reprogramming that allows cells to cope with pathogens and stresses. Likewise, salicylates are important signal molecules for modulating plant responses to environmental stresses. Salicylic acid influences a range of diverse processes in plants, including seed germination, stomatal closure, ion uptake and transport, membrane permeability and photosynthetic and growth rate. Understanding the significant roles of these phytohormones in plant biology and from agriculture point of view, the current subject has recently attracted the attention of scientists from across the globe. Therefore, we bring forth a comprehensive book “Jasmonates and Salicylates Signalling in Plants” highlighting the various prospects involved in the current scenario. The book comprises chapters from diverse areas dealing with biotechnology, molecular biology, proteomics, genomics, metabolomics, etc. We are hopeful that this comprehensive book furnishes the requisite of all those who are working or have interest in this topic.

Bei vielen physiologischen und Entwicklungsprozessen sowie bei Stressreaktionen spielen Hormonsignale, die Pflanzen aussenden, eine große Rolle. Mit Aufkommen der neuen post-genomischen Molekulartechnologien sind auch unsere Möglichkeiten, die Wirkung von Hormonsignalen auf die Genexpression und adaptive Prozesse zu verstehen, heute einzigartig. Wenn wir die molekularen Grundlagen dieser Prozesse entschlüsseln, ergeben sich für die Entwicklung neuer Pflanzenbiotechnologien und verbesserter Varianten von Kulturpflanzen große Chancen. Die Themen dieses Buches legen den Schwerpunkt auf die Genomik und funktionale Aspekte der Genomik. Damit lassen sich globale Veränderungen und Veränderungen auf Ebene des gesamten Genoms unter spezifischen Stressbedingungen verstehen. Mit funktionalen Werkzeugen der Genomik kann der Mechanismus von Phytohormonsignalen in Verbindung mit den zugehörigen Zielgenen systematischer definiert werden. Die integrierte Analyse von Phytohormonsignalen bei einzelnen oder mehreren Stressbedingungen ist unter Umständen für die Entwicklung stresstoleranter Kulturpflanzen eine außergewöhnliche Möglichkeit. Mechanism of Plant Hormone Signaling Under Stress beschreibt die jüngsten Fortschritte und zeigt, wie heutige Erkenntnisse in der wissenschaftlichen Erforschung von Pflanzen und Kulturpflanzen Anwendung finden. Dieses Buch ist für Pflanzenbiologen, Biologen, die sich mit Stressfaktoren beschäftigen, Forscher im Bereich Pflanzenbiotechnologie, Studenten und Dozenten überaus nützlich.

Although the role of salicylic acid (SA) in plant physiological processes has been widely studied for a long time, many open questions remain several fields. The importance of SA synthesis is illustrated by the four review papers published in this Special Issue that represent a wide range of approaches, indicating that a growing body of evidence needs to be summarized in a thought-provoking manner. The investigations presented in the six original studies extend upon the understanding of the involvement of SA in anthracnose infection and light-dependent cold acclimation, highlighting the use of SA mutant Arabidopsis plants. The studies also focused on the application of novel SA analogs or SA in combination with Rhizobacteria inoculation. We hope that the four reviews and six studies provide a deeper understanding of the role of SA and its complex tasks, as well as a new direction for research to address gaps and open questions, including both at the metabolite and gene expression levels, in the use of agriculturally important crop or mutant model plants, and in both basic research and practical applications.

Plant Signaling Molecule: Role and Regulation under Stressful Environments explores tolerance mechanisms mediated by signaling molecules in plants for achieving sustainability under changing environmental conditions. Including a wide range of potential molecules, from primary to secondary metabolites, the book presents the status and future prospects of the role and regulation of signaling molecules at physiological, biochemical, molecular and structural level under abiotic stress tolerance. This book is designed to enhance the mechanistic understanding of signaling molecules and will be an important resource for plant biologists in developing stress tolerant crops to achieve sustainability under changing environmental conditions. - Focuses on plant biology under stress conditions - Provides a compendium of knowledge related to plant adaptation, physiology, biochemistry and molecular responses - Identifies treatments that enhance plant tolerance to abiotic stresses - Illustrates specific physiological pathways that are considered key points for plant adaptation or tolerance to abiotic stresses