An Overview of Metal and Metalloid Toxicity and Signaling in Plants

Anthropogenic factors are mostly to blame for the rising incidences of metal and metalloid toxicity in the world. Given that it has an effect on the production of crops; metals and metalloids can go through the food chain and, lead to bio-magnification and subsequent environmental changes that affect human health. Throughout evolution, plants have created sophisticated defenses against these biotic and abiotic stressors. The accumulation of these heavy metals and metalloids disrupts essential functions in plant cells. By producing excess reactive oxygen species, indirectly or directly, heavy metals can affect plants in a number of ways. By enhancing defense responses, including sequestration within vacuoles, metal chelation, metal intake regulation via transporters, and anti-oxidative process amplification, plants combat such environmental metal overexposure. Plants respond to these stressors in this manner and the complex signaling networks interact within the cell to translate external inputs into an intracellular reaction. The 3 important signaling mechanisms involved—calcium, hormone, and mitogen-activated protein kinase (MAPK) signaling are addressed herein book chapter. A significant element in controlling heavy metal stress is played by regulators other than signaling components, including microRNAs and transcription factors. This book chapter highlights the critical part MAPKs play in synchronizing control of other signaling regulators and components in stress caused by metals. Additionally, we also discussed chelators and metal transporters which are controlled by mitogen-activated protein kinase signaling.