ABSTRACT
Accumulation of heavy metals in soils is the most prevalent type of abiotic stress. Heavy metal toxicity depreciates the plant growth and development process. Some of these heavy metals can be of essential nature however their presence in excess can be detrimental for plants. These metals target the vital molecules and influence the physiology and metabolism of the plants. Heavy metal toxicity leads to oxidative stress by accumulation of reactive oxygen species (ROS). Plants act against these factors on molecular, cellular, and physiological levels. Metal sequestration into vacuole, regulation of metal intake by transporters, chelation, and escalation of antioxidative mechanisms are some of the main responses against metal toxicity. These responses are result of intricate signaling and transduction pathways which eventually result into these defense mechanisms. The pivotal signaling components are transcription factors (TFs) which control the expression of different stress-responsive genes and defense proteins. AP2/ERF, bZIP, MYB, NAC, WRKY TFs have been proved to have a pivotal role in alleviating as well as adapting to heavy metal stress. The genes responsible for TFs can do wonders in modifying the crops such that they can adapt in heavy metal-rich soils.
