Salicylic Acid as Plant Biostimulant

Dear Colleagues,

Anthropogenic activities intensify the negative impact of climate change, compromising the ability to produce sufficient food. The increasing demand for sustainable biosolutions in agriculture has brought biostimulants to the forefront as valuable tools for regenerative farming. Given their varied biological activities, biostimulants play a key role in enhancing crop growth, improving nutrient efficiency, sustaining resilience to environmental stressors, and restoring soil health. Salicylic acid (SA) is an essential plant hormone interconnected with other plant hormones. It can mitigate the accumulation of excessive reactive oxygen species (ROS), effectively acting as an antioxidant and plant growth regulator, while modulating the adverse effects of biotic and abiotic stresses. Salicylic acid affects a variety of physiological, biochemical, and developmental processes, e.g., stomatal closure, membrane permeability, seed germination, photosynthesis, transpiration rate, plant immunity, and growth yield. By modulating the expression of pathogenesis-related (PR) genes, influencing redox homeostasis, and regulating programmed cell death (PCD), it contributes to the hypersensitive response (HR) against pathogens while also affecting cellular differentiation and metabolic adaptation. SA belongs to a diverse group of plant phenolics which have been associated with the chemical defense of plants against microbes, insects, and herbivores. During abiotic stress conditions, minimal concentrations of SA can induce the synthesis of osmolytes, such as proline, ameliorating osmotic potential. The impact of salicylic acid on plants may differ depending on the plant species, concentration used, exposure time, and the way it is applied. Salicylic acid has been suggested to have potential for mitigating abiotic stress in major agricultural crops, improving their stress resistance, and acting as an antioxidant, osmo-regulator, biostimulant, and signaling molecule in systemic acquired resistance (SAR) and local defense mechanisms.

This Topic will help elucidate the molecular mechanisms of SA activity on plant metabolism and will highlight the complexity of SA interactions with other hormones in activating a regulatory response network to environmental stresses. This knowledge will enhance our understanding of plant responses to stress factors, which can help in the development of realistic interventions to increase agricultural productivity. Scientists from all around the world are invited to submit original research and review articles on the impact of SA on any aspects related to crop agriculture and plant physiology and development, including growth, water relations, nutrition, photosynthesis, and other related plant physiological processes.

Prof. Dr. Michael Moustakas
Dr. Julietta Moustaka
Topic Editors