Functional analysis of <i>PagERF021</i> gene in salt stress tolerance in <i>Populus alba × P. glandulosa</i>

Poplar trees are crucial for timber and greening, but high levels of salt in the soil have severely limited the yield of poplar. Ethylene response factor (ERF) transcription factors play an important role in growth, development, and stress response in eukaryotes. Our study focused on the PagERF021 gene from Populus alba × P. glandulosa, which was significantly upregulated in various tissues under salt stress [Correction added on October 4, 2024, after first online publication: "ETS2 reporter factor" is changed to "Ethylene response factor".]. Both the tissue-specific expression pattern and β-glucuronidase (GUS) staining of proPagERF021-GUS plants indicated that this gene was predominantly expressed in the roots and stems. The subcellular localization showed that the protein was only localized in the nucleus. The yeast assay demonstrated that this protein had transcriptional activation activity at its C-terminal and could specifically binding to the MYB-core cis-element. The overexpression of PagERF021 gene could scavenge the accumulation of reactive oxygen species and reduce the degree of cellular membrane damage, indicating that this gene enhanced the salt tolerance of poplars. This finding will provide a feasible insight for future research into the regulatory mechanisms of ERF genes in resisting to abiotic stress and the development of new stress-resistant varieties in plants.