Salicylic acid and heavy metal stress: current understanding and emerging perspectives

Salicylic acid (SA) is a phenolic intrinsic plant growth regulator that affects plants' various metabolic and physiological processes, influencing their development, proliferation, photosynthesis, and other metabolic functions. In the last few decades, SA has drawn a lot of interest for its function in signaling resistance to various abiotic stresses, including temperature, salinity, ozone, and heavy metals (HMs)/metal(loid)s. Soil pollution with HMs/metal(loid)s from natural and anthropogenic processes has become a global issue in recent years, affecting the environment and human health. Due to the rapid rate at which pollution is growing, it is imperative to create efficient systems that can aid in maintaining agricultural productivity and food quality. Finding techniques to boost tolerance is a huge challenge for plant biologists. So, the present review focuses on SA's physiological functions and mechanisms in developing plant HMs/metal(loid)s stress tolerance. SA interacts with various plant hormones during HMs/metal(loid)s stress, and encourages the production of antioxidant compounds and enzymes, which reduce HMs/metal(loid)s stress in plants. So, the current review examines recent literature on the functions and mechanisms of SA in plants affected by HMs/metal(loid)s stress to offer a comprehensive picture of SA and HMs/metal(loid)s and to guide future studies in this area.