Current Protein and Peptide Science - Volume 22, Issue 5, 2021

Abiotic stresses arising from atmosphere change belie plant growth and yield, leading to food reduction. The cultivation of a large number of crops in the contaminated environment is the main concern of environmentalists at present. To achieve food safety, a highly developed nanotechnology is a useful tool for promoting food production and assuring sustainability. Nanotechnology helps in better production in agriculture by promoting the efficiency of inputs and reducing relevant losses. This review examines the research performed in the past to show how zinc oxide nanoparticles (ZnO-NPs) influence the negative effects of abiotic stresses. The application of ZnO-NPs is one of the most effectual options for considerable enhancement of agricultural yield globally under stressful conditions. ZnO-NPs can transform the agricultural and food industry with the help of several innovative tools in reversing oxidative stress symptoms induced by abiotic stresses. In addition, the effect of ZnO-NPs on physiological, biochemical, and antioxidative activities in various plants has also been examined properly. This review summarizes the current understanding and the future possibilities of plant-ZnO-NPs research.

Being sessile organisms, plants are persistently confronted by a diverse array of biotic agents, including viruses, bacteria, fungi, herbivores, and nematodes. Understanding the mechanism of host-pathogen interactions is essential for improving plant resistance against these biotic factors. In this review, we have discussed various means and mechanisms by which pathogens influence the host plant defense. A virulent pathogen can reduce the growth and development of a plant, which eventually lowers its yield by multiple processes, like enhancement in cell death, as well as modification of plant architecture. This review also explains the various strategies used by plants to control pathogen-caused diseases. These mainly include either resistance or tolerance by activating cell signaling pathways, which further regulate the synthesis and accumulation of several cellular products, such as phytohormones, enzymes, proteins, and secondary metabolites. To minimize the influence of infection on their vigor, plants also exhibit immunity regardless of the amount of pathogen multiplication. The current review provides an important insight into the mechanisms of host-pathogen interaction, which is very significant for efficient disease management.

Many unfavorable stress conditions, such as wounding, drought, extreme temperatures, salinity and pathogen attacks, control growth, development and plant yield. To survive in such environments, plants have developed many strategies. They are able to induce the expression of a large number of genes that encode effectors, receptors, as well as signaling proteins and protective molecules. Among all, pathogenesis-related proteins (PRs) were found to be activated in response to different biotic and abiotic threats. Those proteins have a wide range of functions; acting as chitinases, peroxidases, anti-microbial agents, hydrolases, protease inhibitors, and other activities. Activation of PR proteins has been demonstrated in different plant families as a response to different stresses. In this review, we have summarized the structural, biological and functional characteristics of the different PRs families in plants, their regulation, as well as their roles in plant defense against abiotic and biotic stresses.

Harsh or extreme environmental conditions largely determine the vegetative and reproductive development of plants. In the case of cultivated plants, their growth and yield are clearly diminished if they are exposed to severe conditions such as drought, waterlogging, extreme heat or cold, UV radiation, or toxic substances in the soil such as salts, heavy metals and pesticides. Melatonin has been studied for decades as a molecule capable of reducing the negative effects of abiotic stressors by increasing tolerance to these adverse growth conditions. This work presents a review of the most outstanding studies with various plant species in each of the above-mentioned stress situations, including proteomic and post-translational studies. Melatonin mediates plant responses to abiotic stress, generally inducing an antioxidative response, and also regulating a complex gene response adapted to individual stressors. Plants are able to increase their endogenous melatonin levels through the application of exogenous melatonin or through the inductive mechanism of endogenous melatonin biosynthesis. In such ways, plants are able to cope with the stressful situation at hand, accommodating their metabolism, morphology and physiology in order to increase overall survival and induce greater tolerance to stress. The agronomic implications of the use of melatonin are discussed.

Plants, as sessile organisms, are susceptible to a myriad of stress factors, especially abiotic stresses. Over the course of evolution, they have developed multiple mechanisms to sense and transduce environmental stimuli for appropriate responses. Among those, phosphorylation and dephosphorylation, regulated by protein kinases and protein phosphatases, respectively, are considered crucial signal transduction mechanisms. Regarding the latter group, protein phosphatases type 2C (PP2Cs) represent the largest division of PPs. In addition, the discovery of regulatory functions of PP2Cs in the abscisic acid (ABA)-signaling pathway, the major signal transduction pathway in abiotic stress responses, indicates the significant importance of PP2C members in plant adaptation to adverse environmental factors. In this review, current understanding of the roles of PP2Cs in different phytohormone-dependent pathways related to abiotic stress is summarized, highlighting the crosstalk between the ABA-signaling pathway with other hormonal pathways via certain ABA-related PP2Cs. We also updated the progress of in planta characterization studies of PP2Cs under abiotic stress conditions, providing knowledge of PP2C manipulation in developing abiotic stress-tolerant crops.