Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Global climate change and associated adverse abiotic stress conditions, such as drought, salinity, heavy metals, waterlogging, extreme temperatures, oxygen deprivation, etc., greatly influence plant growth and development, ultimately affecting crop yield and quality, as well as agricultural sustainability in general. Plant cells produce oxygen radicals and their derivatives, so-called reactive oxygen species (ROS), during various processes associated with abiotic stress. Moreover, the generation of ROS is a fundamental process in higher plants and employs to transmit cellular signaling information in response to the changing environmental conditions. One of the most crucial consequences of abiotic stress is the disturbance of the equilibrium between the generation of ROS and antioxidant defense systems triggering the excessive accumulation of ROS and inducing oxidative stress in plants. Notably, the equilibrium between the detoxification and generation of ROS is maintained by both enzymatic and nonenzymatic antioxidant defense systems under harsh environmental stresses. Although this field of research has attracted massive interest, it largely remains unexplored, and our understanding of ROS signaling remains poorly understood. In this review, we have documented the recent advancement illustrating the harmful effects of ROS, antioxidant defense system involved in ROS detoxification under different abiotic stresses, and molecular cross-talk with other important signal molecules such as reactive nitrogen, sulfur, and carbonyl species. In addition, state-of-the-art molecular approaches of ROS-mediated improvement in plant antioxidant defense during the acclimation process against abiotic stresses have also been discussed.

Reactive Oxygen Species and Antioxidant Defense in Plants under Abiotic Stress: Revisiting the Crucial Role of a Universal Defense Regulator

Phenolic compounds are an important class of plant secondary metabolites which play crucial physiological roles throughout the plant life cycle. Phenolics are produced under optimal and suboptimal conditions in plants and play key roles in developmental processes like cell division, hormonal regulation, photosynthetic activity, nutrient mineralization, and reproduction. Plants exhibit increased synthesis of polyphenols such as phenolic acids and flavonoids under abiotic stress conditions, which help the plant to cope with environmental constraints. Phenylpropanoid biosynthetic pathway is activated under abiotic stress conditions (drought, heavy metal, salinity, high/low temperature, and ultraviolet radiations) resulting in accumulation of various phenolic compounds which, among other roles, have the potential to scavenge harmful reactive oxygen species. Deepening the research focuses on the phenolic responses to abiotic stress is of great interest for the scientific community. In the present article, we discuss the biochemical and molecular mechanisms related to the activation of phenylpropanoid metabolism and we describe phenolic-mediated stress tolerance in plants. An attempt has been made to provide updated and brand-new information about the response of phenolics under a challenging environment.

https://www.mdpi.com/1420-3049/24/13/2452/pdf

Response of Phenylpropanoid Pathway and the Role of Polyphenols in Plants under Abiotic Stress.

Pesticides are extensively used in modern agriculture and are an effective and economical way to enhance the yield quality and quantity, thus ensuring food security for the ever-growing population around the globe. Approximately, 2 million tonnes of pesticides are utilized annually worldwide, where China is the major contributing country, followed by the USA and Argentina, which is increasing rapidly. However, by the year 2020, the global pesticide usage has been estimated to increase up to 3.5 million tonnes. Although pesticides are beneficial for crop production point of view, extensive use of pesticides can possess serious consequences because of their bio-magnification and persistent nature. Diverse pesticides directly or indirectly polluted air, water, soil and overall ecosystem which cause serious health hazard for living being. In the present manuscript, an attempt has been made to critically review the global usage of different pesticides and their major adverse impacts on ecosystem, which will provide guidance for a wide range of researchers in this area.

/pdf/worldwide-pesticide-usage-and-its-impacts-on-ecosystem-4wx35yntrp.pdf

Worldwide pesticide usage and its impacts on ecosystem

Nothing is solid about proteins. Governing rules and established laws are constantly broken. As an example, the last decade and a half have witnessed the fall of one of the major paradigms in structural biology. Contrarily to the more than a century-old belief that the unique function of a protein is determined by its unique structure, which, in its turn, is defined by the unique amino acid sequence, many biologically active proteins lack stable tertiary and/or secondary structure either entirely or at their significant parts. Such intrinsically disordered proteins (IDPs) and hybrid proteins containing ordered domains and functional IDP regions (IDPRs) are highly abundant in nature, and many of them are associated with various human diseases. Such disordered proteins and regions are very different from ordered and well-structured proteins and domains at a variety of levels and possess well-recognizable biases in their amino acid compositions and amino acid sequences. A characteristic feature of these proteins is their exceptional structural heterogeneity, where different parts of a given polypeptide chain can be ordered (or disordered) to different degrees. As a result, a typical IDP/IDPR contains a multitude of potentially foldable, partially foldable, differently foldable or not foldable structural segments. This distribution of conformers is constantly changing in time, where a given segment of a protein molecule has different structures at different time points. The distribution is also constantly changing in response to changes in the environment. This mosaic structural organization is crucial for their functions and many IDPs are engaged in biological functions that rely on high conformational flexibility and that are not accessible to proteins with unique and fixed structures. As a result, the functional repertoire of IDPs complements that of ordered proteins, with IDPs/IDPRs being often involved in regulation, signaling and control. This Sprenger Briefs volume is dedicated to IDPs and IDPRs and an attempt is made to compress a massive amount of knowledge and into a digest that aims to be of use to those wishing a fast entry into this promising field of structural biology.

Intrinsically Disordered Proteins

Cross Talk Among Reactive Oxygen, Nitrogen and Sulfur During Abiotic Stress in Plants

Osmolytes and osmoprotectants have long been identified as pivotal abiotic stress busters because they help plants overcome extremely harsh environmental conditions by constant cellular homeostatic monitoring. This group mainly consists of sugars, polyols, amino acids, and betaines. Together, they shield plants by exercising a number of physiological responses such as membrane integrity strengthening, enzymatic/antioxidant activity balancing, and water adjustments under various abiotic stresses (e.g., temperature fluctuations, water deficit, salinity, heavy metals) and, more recently, pesticide exposure. Crop plant cultivation across the globe needs such comprehensive protection strategies against a vast array of ever-changing environmental conditions by developing tolerance at genetic and molecular levels. Currently, this is being achieved via osmoprotectant genetic engineering of plant genomes and exogenous application of antistress agents to crop plants to obtain high-yield, stress-resistant varieties. A newer modification to this two-dimensional approach is osmoprotectant activation via “omics”—an integral approach comprised of genomics, metabolomics, and transcriptomics. This chapter gives a cumulative account of their biosynthesis, classification, and functioning with respect to transgene induction, exogenous application, and omic approaches for an improved agricultural dimension.

Chapter 17 – Osmolyte Dynamics: New Strategies for Crop Tolerance to Abiotic Stress Signals

Boron in plants: uptake, deficiency and biological potential

The present investigation has been an attempt to evaluate antifungal and antioxidant potential of two ethno botanically important liverworts viz, Plagiochasma appendiculatum and Pellia endivaefolia. The methanolic extract was tested against three fungal species viz. Alternaria alternata, Aspergillus flavus and Aspergillus niger. Plagiochasma sp. proved to be more effective against all tested fungi; especially, A. flavus. Similarly Pellia sp. inhibited A. alternata the most. The antioxidant system viz. antioxidants and antioxidant enzymes were also evaluated. The values were enough closer to those of higher plants. Guaiacol peroxidase and catalase activity of Plagiochasma sp. was found to be higher than that of Pellia sp. All other evaluated parameters like superoxide dismutase, ascorbic acid, proline, glutathione and total phenols were higher in Pellia sp. as compared to Plagiochasma sp. This is the first report regarding the antioxidant system of these two liverworts.

Antifungal and Antioxidant Profile of Ethnomedicinally Important Liverworts ( Pellia endivaefolia and Plagiochasma appendiculatum ) Used by Indigenous Tribes of District Reasi: North West Himalayas

Plants are sessile organisms that use a large number of signals either originated in their body or in the environment, which help them to regulate the behavior of their body. In agricultural systems, abiotic stress is one of the challenging threats that lead to serious reduction in growth and development of crop plants. To thrive in such adverse conditions of nature, plants have well-developed mechanisms to perceive the stress signals and respond accordingly. During abiotic stress conditions, plant growth regulators act as signal molecules and initiate signal transduction via secondary messengers that activate downstream metabolic pathways resulting in alteration of gene expression. The present chapter makes an approach to emphasize the role of various plant hormones in abiotic stress conditions.

Neha Handa

Papers

Cross Talk Among Reactive Oxygen, Nitrogen and Sulfur During Abiotic Stress in Plants

Chapter 17 – Osmolyte Dynamics: New Strategies for Crop Tolerance to Abiotic Stress Signals

Boron in plants: uptake, deficiency and biological potential

Antifungal and Antioxidant Profile of Ethnomedicinally Important Liverworts ( Pellia endivaefolia and Plagiochasma appendiculatum ) Used by Indigenous Tribes of District Reasi: North West Himalayas

Role and Regulation of Plant Hormones as a Signal Molecule in Response to Abiotic Stresses