Search

Plants face a range of environmental stresses, such as heat and drought, that significantly reduce their growth, development, and yield. Plants have developed complex signaling networks to regulate physiological processes and improve their ability to withstand stress. The key regulators of plant stress responses include polyamines (PAs) and gaseous signaling molecules (GSM), such as hydrogen sulfide (H2S), nitric oxide (NO), methane (CH4), carbon monoxide (CO), carbon dioxide (CO2), and ethylene (ET). The functions of PAs and GSM in stress perception, signal transduction, and stress-responsive pathways have been explored. However, there is a lack of detailed, updated information on the interaction of PAs and GSM in the adaptation of drought and heat stress. This review explores the interaction between PAs and GSM for the adaptation to drought and heat stress. It explores their synergistic effects in mitigating the negative impacts of drought and heat stress on plant growth, development, and productivity. Moreover, a comprehensive analysis of physiological, biochemical, and molecular approaches demonstrates that their interaction activates key stress-responsive pathways, enhances antioxidant systems, and modulates gene expression. These combined effects contribute to improved drought and heat tolerance in plants. The information presented in the review provides valuable insights into plant stress resilience strategies and suggests potential measures for developing climate-resilient crops to address the increasing environmental challenges. [ABSTRACT FROM AUTHOR]

Lignans are a prominent group of phenolic compounds ubiquitously present in the plant kingdom, playing a critical role in both plant physiology and human health. Structurally they are characterized by the dimerization of two phenylpropane units to attain diverse chemical configurations that contribute to their wide range of biological activities. In plants, lignans function primarily as defense molecules, protecting against pathogens, herbivores, and environmental stressors. These compounds also participate in plant growth regulation and lignification processes. From a nutritional and medicinal perspective, lignans are valued for their significant health benefits. They act as phytoestrogens, which can modulate estrogen receptors in humans, thereby offering protective effects against hormone-related diseases such as breast cancer and menopausal symptoms. Additionally, lignans possess potent antioxidant and anti-inflammatory properties, contributing to cardiovascular health and cancer prevention. This review aims to provide a comprehensive overview of the importance of lignans in plants, highlighting their chemical diversity, health-promoting properties and stress adaptation. By synthesizing recent research findings, this review underscores the significance of lignans in enhancing plant resilience under stress and human health. It explores their potential applications in the food and pharmaceutical industries. Besides, it will also focus on the widely used method for enhancing the production of these high-value secondary metabolites in plant cell cultures to meet their requirement in pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Ethylene is an essential plant hormone, critical in various physiological processes. These processes include seed germination, leaf senescence, fruit ripening, and the plant's response to environmental stressors. Ethylene biosynthesis is tightly regulated by two key enzymes, namely 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO). Initially, the prevailing hypothesis suggested that ACS is the limiting factor in the ethylene biosynthesis pathway. Nevertheless, accumulating evidence from various studies has demonstrated that ACO, under specific circumstances, acts as the rate-limiting enzyme in ethylene production. Under normal developmental processes, ACS and ACO collaborate to maintain balanced ethylene production, ensuring proper plant growth and physiology. However, under abiotic stress conditions, such as drought, salinity, extreme temperatures, or pathogen attack, the regulation of ethylene biosynthesis becomes critical for plants' survival. This review highlights the structural characteristics and examines the transcriptional, post-transcriptional, and post-translational regulation of ACS and ACO and their role under abiotic stress conditions. Reviews on the role of ethylene signaling in abiotic stress adaptation are available. However, a review delineating the role of ACS and ACO in abiotic stress acclimation is unavailable. Exploring how particular ACS and ACO isoforms contribute to a specific plant's response to various abiotic stresses and understanding how they are regulated can guide the development of focused strategies. These strategies aim to enhance a plant's ability to cope with environmental challenges more effectively. [ABSTRACT FROM AUTHOR]

During climate change, various unparalleled perils to agricultural systems have been observed worldwide. The detrimental impacts of heavy metal toxicity (HMs) lead to a considerable decrease in crop productivity and yield, thereby putting the agricultural system at risk and exerting a significant impact on food production. This has sparked significant worry regarding the achievement of the sustainable development goals (SDGs) pertaining to ensuring food and nutritional security for the constantly growing global population. In the current study, we have endeavored to reveal the significance of salicylic acid (SA) under arsenic (As) stress conditions in rice (Oryza sativa) plants. Being a toxic metalloid, As has adverse effects on the efficiency of photosynthesis and the assimilation of nitrogen (N) and sulphur (S) growth, and also causes alterations in defense systems and ethylene biosynthesis. The study revealed that the positive influence of SA in promoting nutrient metabolism, photosynthesis and growth under As stress was the result of its interplay with ethylene biosynthesis and the enhanced capacity of defense systems to reduce oxidative stress-mediated cellular injuries and cell deaths. In conclusion, SA can be considered a crucial physiological criterion for the development of As-tolerant rice plants. [ABSTRACT FROM AUTHOR]

In plants, sulfur plays a critical role in the formation of important biomolecules such as cysteine, methionine, and tripeptide glutathione. Thiol groups, composed of sulfur, are essential to numerous metabolic processes. The easy and reversible oxidation and reduction of thiol groups have drawn attention to the redox regulation of cellular metabolism. Reactive sulfur species (RSS), including hydrogen sulfide (H2S), persulfides, and polysulfides, are synthetized in all living organisms, mainly from cysteine, and have been recognized in the last two decades as very important molecules in redox regulation. RSS are considered potent signaling molecules, being involved in the regulation of virtually all aspects of cell function. With regard to stress, reactive species and the antioxidant machinery maintain a delicate balance that gets disturbed under stress conditions, wherein reactive species biosynthesis, transportation, scavenging, and overall metabolism become decisive for plant survival. While reactive oxygen and nitrogen species have been much discussed over recent years, research into RSS biosynthesis, signaling, and relation to abiotic stresses is still nascent. RSS evolved long before reactive oxygen species, and because both are metabolized by catalase, it has been suggested that "antioxidant" enzymes originally evolved to regulate RSS and may still do so today. In this review, we have tried to summarize the generation, signaling, and interaction of RSS in plant systems and to discuss in detail the roles under various abiotic stresses. [ABSTRACT FROM AUTHOR]