Transcriptomics combined with physiological analysis provided new insights into the enhancing Dendrobium nobile resilience to Cu stress through Ce modulation

Abstract

In the face of escalating environmental challenges, understanding the mechanisms through which plants can resist heavy metal stress is paramount. This study delves into the efficacy of cerium (Ce), a rare earth element, in mitigating copper (Cu) toxicity in Dendrobium nobile Lindl., an orchid plant with significant medicinal and ornamental value. Through a comprehensive experimental approach that encompasses physiological, biochemical, and molecular analyses, we demonstrate that Ce application notably enhances D. nobile's tolerance to Cu stress. The investigation revealed that Ce supplementation significantly ameliorated the adverse effects of Cu on plant growth, evidenced by a notable decrease in Cu accumulation within the plant tissues. At the molecular level, transcriptome sequencing uncovered the upregulation of genes involved in antioxidant defense mechanisms, heavy metal chelation, and stress response signaling pathways. Key findings include the enhanced activities of antioxidant enzymes such as superoxide dismutase, peroxidase, and catalase, alongside an increase in the levels of antioxidants and phytochelatins, which collectively contribute to the detoxification of Cu. Furthermore, Ce was found to influence the subcellular distribution of Cu, promoting its sequestration in less harmful cellular compartments. Our study provides novel insights into the role of Ce in modulating plant responses to heavy metal stress, highlighting its potential as a mitigative agent against Cu toxicity. The elucidation of specific gene regulations and pathway activations offers a foundation for future research aimed at enhancing plant resilience to environmental stresses through biotechnological interventions.