Heavy metal priming plant stress tolerance deciphering through physiological, biochemical, molecular and omics mechanism

In the wake of rapid industrialization and human-induced environmental changes, toxic heavy metal pollution has become a widespread concern, posing a significant threat to crop plants. This paper explores the mechanisms of plant stress tolerance in the face of heavy metal toxicity. Plants have evolved defense strategies, including reduced metal uptake, phytochelatin binding, and robust antioxidant systems, to counter these challenges. Our study focuses on deciphering these mechanisms through advanced omics technologies like genomics, transcriptomics, miRNAomics, metallomics, and metabolomics. These insights offer practical methods to enhance stress tolerance in crops and develop resilient genotypes. Key enzymes such as peroxidase, superoxide dismutase, and catalase, along with non-enzymatic antioxidants like ascorbic acid, play pivotal roles in plant defense against heavy metal stress. Both essential and non-essential metals induce adverse effects in plants, from inhibited growth to impaired photosynthesis, ultimately impacting plant survival. Effective defense tactics involve not only enzymatic and non-enzymatic antioxidants but also root exudates and cell wall reinforcement. This review provides a concise exploration of the complex mechanisms underlying plant stress tolerance, covering metal uptake, transport, damage, and chelation within cellular components. It sheds light on how plants adapt to thrive amidst these challenging stress factors.