**5. Conclusions**

In conclusion, the AP2/ERF superfamily gene *IlAP2*, confirmed to interact with *IlMT2a* in this study, was analyzed using quantitative real-time PCR, transgenics and transcriptome sequencing to understand its regulation function and mechanism in improving plant tolerance to cadmium stress. The results showed that *IlAP2* could interact with IlMT2a in the nucleus and may cooperate with other transcription factors to regulate genes related to signal transduction and plant hormones, leading to reduced cadmium toxicity. These findings provide insights into the mechanism of *IlAP2*-mediated stress responses to cadmium and highlight *IlAP2* as an important gene resource for improving plant stress tolerance in phytoremediation to manage cadmium soil contamination.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/plants12040823/s1, Figure S1: Relative changes in expression of genes analyzed using qRT-PCR; Table S1: 1/2 Hoagland's solution composition.

**Author Contributions:** Conceptualization, Z.W. and C.G.; formal analysis, L.N. and Z.W.; investigation, Z.W., L.N., L.L. and H.Y.; writing—original draft preparation, Z.W. and L.N.; writing—review and editing, Z.W. and C.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (31772351) and the 333 Talents Project of Jiangsu Province (BRA2017498).

**Data Availability Statement:** No new data were created or analyzed in this study. Data sharing is not applicable to this article.

**Conflicts of Interest:** The authors declare no conflict of interest.
