Mechanisms of Copper Stress Response in Plants: Implications for the Medicinal Plant Platycodon grandiflorus.
- 2026-06-15
- Biology 15(12)
- Chi Liu
- Shan Jiang
- Junbai Ma
- Meitong Pan
- WenJing Sun
- Denghua Wen
- Ruoxi Zhang
- Wei Ma
- Xiubo Liu
- PubMed: 42345790
- DOI: 10.3390/biology15120934
Study Design
- Type
- Review
Copper is an essential trace element for plant growth; however, in excessive amounts, it can cause severe toxicity by inducing bursts of reactive oxygen species and disrupting metabolic balance. As a root-based medicinal plant and food, Platycodon grandiflorus has its roots in direct contact with the soil. Its ability to accumulate copper is the most pronounced among various heavy metals; consequently, it is particularly susceptible to copper stress, which in turn affects its normal growth and medicinal quality. This paper focuses on the intrinsic stress potential and possible response pathways of Platycodon grandiflorus to copper stress. Drawing on existing research and relevant literature, it conducts an integrated analysis of its defence mechanisms across four levels: physical barriers, non-enzymatic antioxidants, conserved physiological and biochemical pathways, and transcriptional regulation. Regarding physical barriers, the cell wall forms the first line of defence through pectin adsorption and lignin deposition; in terms of endogenous antioxidant defence, secondary metabolites such as polysaccharides and saponins can directly participate in the scavenging of reactive oxygen species; regarding conserved pathways, the glutathione-phytochelate system acts in concert with antioxidant enzymes such as SOD and CAT to participate in copper ion chelation and the alleviation of oxidative stress, with hormone signalling regulation also playing a crucial coordinating role in this process; regarding transcriptional regulation, transcription factors such as PgWRKY may mediate the perception of stress signals and the expression of downstream genes. These pathways act in a coordinated and sequential manner, collectively forming a multi-level defence network through which Platycodon grandiflorus responds to copper stress. At the same time, this paper highlights the functional limitations of this defence system, summarises the shortcomings in current research, and proposes directions for future studies, with a view to guiding the safe cultivation and quality assurance of Platycodon grandiflorus in copper-polluted areas, as well as for the breeding of heavy-metal-tolerant medicinal plants.