Comparative physiological and transcriptome analysis revealed the role of cerium in alleviating copper stress in Dendrobium nobile Lindl.

Abstract Low concentrations of rare earth elements can be used as mitigants to alleviate metal toxicity in plants. The aim of this experiment was to investigate the mechanism of cerium (Ce) mitigation of copper (Cu) stress in Dendrobium nobile Lindl . It was found that Cu treatment caused significant stress, while Ce spray significantly improved the growth under Cu stress and reduced the Cu content in the plant by 9.48%. Ce promoted photosynthesis of D. nobile and enhanced the ability to scavenge reactive oxygen species by increasing the activity of antioxidant enzymes. Ce combines with heavy metal ions to form chelates and transports Cu into the vesicles, thus reducing the toxicity of metals to plants. Transcriptome analysis revealed 959 differential genes in the Cu + Ce group compared to the Cu group (511up, 458down). Analysis of differential genes related to metabolic pathways for detoxification revealed that Ce can enhance tolerance of D. nobile under Cu stress through various pathways such as regulated metabolic pathways Isoquinoline alkaloid biosynthesis, MAPK signaling pathway, Phenylpropanoid Bioynthesis, Plant hormone signal transduction, Pyruvate metabolism pathway and ABC transporter to regulate GSH, amino acids, metallothionein, thus affecting antioxidant enzyme activity, synergistic ion transport and metal chelate synthesis. GST, AOC3, cat, PP2C, OMT, GCSH, N4OMT, ACS, MKK9, CML may be the key genes in D. nobile to resist Cu stress. This study initially reveals the mechanism of Ce alleviation of Cu stress and lays a theoretical foundation for further research on the molecular regulatory mechanism of D. nobile in adversity.