Phyto Oxylipins

Oxylipins are an important class of signaling molecules in plants, which play an important role in plant defence and innate immunity. Oxylipins have critical roles in plant growth and plant responses to physical damage caused by herbivores, insects, and pathogenic microbes. Over the last decade, our understanding of oxylipin production, metabolism, and function, particularly jasmonates, has advanced considerably. Jasmonates have provided further mechanistic insights into enzyme function and signalling cascades. Other oxylipins, such as hydroxy fatty acids, have recently been shown to exhibit individual signaling features and crosstalk with other phytohormones. There is scant literature on plant oxylipins and their relevance to our understanding and therefore, understanding oxylipin production, metabolism, and function is pivotal. As a result, researchers, students, professors, and other book readers will have a thorough understanding of plant oxylipin biosynthesis, structure, and function, assisting in the improvement of plant science. Plant oxylipins: metabolism, physiological roles, and profiling techniques address the mechanism, metabolism, and roles of oxylipins in plant resistance to various biotic and abiotic stimuli in detail. This book covers fundamental ideas in oxylipin production, metabolism, structural biochemistry, and signaling pathways. It also discusses cutting-edge methodologies for oxylipin metabolic profiling, with an emphasis on computing applications. This book is an excellent resource for plant scientists, plant biochemists, biotechnologists, botanists, phytochemists, toxicologists, chemical ecologists, taxonomists, and other scholars in those subjects. The book is written by a global team of professionals. Features Presents concrete and extensive information about a basic and applied aspect of plant oxylipins as well as expanded coverage of signaling mechanisms. Highlights the fundamental concepts of the biosynthesis, metabolism, structural biochemistry, and signaling pathway of oxylipins. Details the state-of-the-art methods and techniques in metabolic profiling of oxylipins in plants. Presents insights on computational applications in the evaluation and study of oxylipins in plants.

Plants are continuously exposed to different environmental stresses that negatively impact their physiology and morphology, resulting in production reduction. As a result of constant pressure, plants evolve different mechanisms for sustenance and survival. Hormones play a major role in defences against the stresses and stimulate regulatory mechanisms. One of the ways through which they mitigate stress is via the production of hormones like auxins, ethylene, jasmonic acid, etc. The phytohormones help in signaling and enhance the chances of their survival. Plant hormones play many vital roles from integrating developmental events, physiological and biochemical processes to mediating both abiotic and biotic stresses. This book aims to highlight these issues and provide scope for the development of tolerance in crops against abiotic stresses to maximize yield for the growing population. There is an urgent need for the development of strategies, methods and tools for the broad-spectrum tolerance in plants supporting sustainable crop production under hostile environmental conditions. The salient features are as follows: • It includes both traditional and non-traditional phytohormones and focuses on the latest progress emphasizing the roles of different hormones under abiotic stresses. • It provides a scope of the best plausible and suitable options for overcoming these stresses and puts forward the methods for crop improvement. • It is an amalgamation of the biosynthesis of phytohormones and also provides molecular intricacies and signalling mechanisms in different abiotic stresses. • This book serves as a reference book for scientific investigators from recent graduates, academicians and researchers working on phytohormones and abiotic stresses.

The phytochemical constituents of plants fall into two main categories based on their role in basic metabolic processes: primary and secondary. Primary metabolites are involved in basic life functions and are similar in all living cells, whereas secondary metabolites are derived from subsidiary pathways. Although traditionally referred to as secondary metabolites, more recently these compounds have been termed 'plant specialized metabolites', as the exact biochemical boundary between primary and secondary metabolites has not been fully established. Plant specialized metabolites are the main element in the study and use of 'medicinal' plants and herbs, as well as in nutrition and food chemistry. In modern medicine, plant specialized metabolites provide many of the lead compounds in the production of medicines targeted at treating a broad variety of diseases. Such metabolites also play an important role in sessile plants: to resist and withstand different biotic and abiotic stresses. Plant specialized metabolites are classified according to their chemical structures and this book will present the different classes in turn, while discussing their sources and distribution in plant families, their biosynthetic pathways, and their important and notable uses in phytochemistry and pharmacology. Chemical Diversity of Plant Specialized Metabolites will be a useful guide and reference point for chemists and students in many disciplines including synthetic organic chemists, medicinal chemists, plant scientists, pharmacognosists, chemical ecologists, bioengineers, and synthetic biologists, in addition to those working in related fields.

Fungi are sessile, highly sensitive organisms that actively compete for environmental resources both above and below the ground. They assess their surroundings, estimate how much energy they need for particular goals, and then realise the optimum variant. They take measures to control certain environmental resources. They perceive themselves and can distinguish between ‘self’ and ‘non-self’. They process and evaluate information and then modify their behaviour accordingly. These highly diverse competences show us that this is possible owing to sign(aling)-mediated communication processes within fungal cells (intraorganismic), between the same, related and different fungal species (interorganismic), and between fungi and non-fungal organisms (transorganismic). Intraorganismic communication involves sign-mediated interactions within cells (intracellular) and between cells (intercellular). This is crucial in coordinating growth and development, shape and dynamics. Such communication must function both on the local level and between widely separated mycelium parts. This allows fungi to coordinate appropriate response behaviors in a differentiated manner to their current developmental status and physiological influences.

This book focuses on signaling molecules in plant defense, outlining some of the most important cellular and chemical plant defense strategies during periods of stress and growth. Written by leading experts, it covers topics such as the diversity of plant-growth-promoting fungi, the gene-to-metabolite network of plant-microbe interactions, modulation of plant cellular responses to stress, and how plant nutritional deficiency affects crop production. Together with the companion volume Bioactive Molecules in Plant Defense: Saponins, this book offers an essential source of information for postgraduate students and researchers interested in plant pathology, mycology and sustainable agriculture.

Oxophytodienoic acid reductases (OPRs) are flavoenzymes closely related to Old Yellow Enzyme (OYE) from Saccharomyces. The physiological role of plant OPRs could only be clarified for OPR3: OPR3 from tomato and Arabidopsis reduce the double bond of the α,β-unsaturated carbonyl group of (9S,13S)-oxophytodienoic acid (OPDA), the precursor of the phytohormone jasmonic acid (JA). OPR3 is therefore an important step for JA biosynthesis and the following JA-triggered defensive and developmental adaptations of the plant. Since the production of phytohormones, including JA, is regulated in an extremely time- and tissue specific manner, the regulatory step of JA-biosynthesis was sought. The conversion of OPDA by OPR3 was proposed as the rate-limiting step in biosynthesis as OPR3 turned out to form a self-inhibiting dimer when crystallized. In the OPR3 crystal, the L6-loop from each protomer reaches into the active site cavity of the other protomer. The dimerization-dependent block of the active site provides a hypothetical mechanism for the regulation of OPR3 activity. Interestingly, two sulfate ions were enclosed in the interacting site of the protomers, suggesting that the dimer might be stabilized in vivo by reversible sulfation or phosphorylation of the tyrosine 364(SlOPR3) or 365 (AtOPR3), respectively. The role of this hypothesized sulfation/phosphorylation was subject of this study. Neither sulfation nor phosphorylation of Y365 could be detected by mass spectrometry. Hence, studies were continued with an in vitro approach where OPR3 was expressed with sulfotyrosine incorporated co-translationally at position 365 (Y365SY). Biochemical characterization led to contradictory results: On the one hand, interaction strength of Y365SY was unaltered in comparison to wild-type OPR3, while on the other hand, activity of Y365SY was reduced. Closer examination indicated that substrate binding or product release was reduced in Y365SY. These changes could be traced back to the additional charge of the SO42—ion, which leads to a narrowing of the entrance to the active site cavity. With this finding, the proposed regulating mechanism by sulfation/phosphorylation is still valid, but independent from dimerization. In order to link this potential regulatory mechanism with a post-translational modification in vivo, an untargeted screen was performed, in which OPR3 was expressed as a fusion protein with a promiscous biotin ligase (BioID2). With this method, potentially interacting proteins were biotinylated in vivo and subsequently isolated and analyzed by MS/MS. Many candidate proteins were identified for OPR3, including kinases and phosphatases. Additionally, OPR1, OPR2 and OPR4 from Arabidopsis were also expressed as BioID2 fusion proteins in order to clarify their physiological role. The most promising results were obtained for OPR4, which was found to be association with stress granule and P-body proteins.