Comprehensive physiological and transcriptomic analysis revealed the tolerance mechanism of heavy metal cadmium in...

Cd contamination poses significant ecological risks. Quercus dentata, a tree species of high ecological value, exhibits exceptional tolerance to adverse environmental conditions. This study used Q. dentata as material to investigate its physiological response characteristics and potential molecular mechanisms under different concentrations of Cd stress (0, 200, 400, 600 mg/L). Results showed that with increasing stress concentration, the growth and photosynthesis parameters of Q. dentata continued to decline, while cell membrane permeability parameters, antioxidant enzyme activities, osmoregulatory substances, and Cd accumulation in various tissues continued to increase. Transcriptome sequencing also showed significant enrichment of photosynthesis, oxidative stress, amino acid synthesis, and ion binding-related genes (RBOH, SOS, POD). Based on the transcriptomic analysis, we found that numerous transcription factors (MYB, AP2, and WRKY) and heavy metal transport proteins (MTP, OPT, and HMP) played significant roles in the molecular mechanisms of Q. dentata's response to Cd stress. According to qPCR results, we identified the key gene QdMTP10.3, whose expression was continuously upregulated in different tissues with increasing treatment concentrations, conferring Cd²⁺, Fe²⁺, and Mn²⁺ tolerance to yeast cells. In summary, it is concluded that Q. dentata enhances its tolerance to Cd stress by modulating plasma membrane permeability, osmoregulatory substance content, and antioxidant enzyme system activity, while QdMTP10.3 gene plays a pivotal role in Cd response to heavy metal stress similarly, conferring potential for genetic improvement of heavy metal tolerance in plants.