Figure 3.

Oxidative and genotoxic stress in plants in response to heavy metal mediated toxicity. Heavy metal induced oxidative and genotoxic stress response in plants for maintaing the intracellular balance in redox system and genome stability to mitigate the harmful affects of heavy metal mediated oxidative and genotoxic damages. Plant cells activate the antioxidant enzymes and non-enzymatic anti-oxidants like phenylpropanoids for the inactivation and detoxification of heavy metal induced reactive oxygen species to minimixe the oxidative damages of cellular components. The heavy metal induced ROS also causes oxidative damage of bases in the DNA double helix and disrupts the phyco-chemical structure of the DNA, thus influences genome instability, leading the activation of DNA damage response, signaling and repair processes. Role of SOG1 (Suppressor of gamma response1), an unique NAC domain transcription factor in plants, has been shown in coupling the oxidative stress with the genotoxic stress mediated responses via another essential signaling component BRCA1 (breast cancer susceptibility 1) for the activation of various downstream responses, such as DNA damage repair, transcriptional response, cell cycle checkpoint functions and programmed cell death. An interesting switch from cell division to endoreduplication under stress has been indicated as part of stress adaptation mechanism in plant genome.