PtrbZIP12 improves drought resistance in Populus trichocarpa by directly targeting PtrDHN and PtrPOD

Abstract

This research examines how the basic leucine zipper (bZIP) transcription factor (TF) influences drought stress responses in tree species, emphasizing its related regulatory pathways, and thus offering a theoretical framework for understanding drought response mechanisms regulated by the bZIP TF family. Specifically, we characterized the functional role of the S subfamily bZIP gene, PtrbZIP12 , from Populus trichocarpa , by developing transgenic poplars that either overexpressed or knocked down PtrbZIP12 . The findings indicated that PtrbZIP12 markedly improved drought tolerance in transgenic plants by facilitating reactive oxygen species scavenging, enhancing proline biosynthesis, and reducing plasma membrane peroxi- dation and cell death. To pinpoint PtrbZIP12 ’s downstream targets, RNA sequencing was performed, followed by chromatin immunoprecipitation-PCR (ChIP-PCR), yeast one-hybrid, and dual-luciferase assays. These analyses confirmed that PtrbZIP12 binds directly to the promoters of PtrDHN (dehydrin) and PtrPOD (peroxidase), leading to the activation of their expression. Transgenic poplars overexpressing (OE) PtrDHN or PtrPOD were subsequently generated, and similar to PtrbZIP12 , their OE conferred enhanced drought tolerance. Moreover, coexpression of PtrbZIP12 with PtrbZIP3 further elevated PtrDHN transcript levels, resulting in improved drought resilience in the PtrbZIP12 transgenic lines. Moreover, phosphorylation was identified as a key factor in boosting PtrbZIP12-mediated transcriptional regulation of PtrPOD and PtrDHN , underscoring the significance of posttranslational modification in plant drought stress responses.

Acknowledgements

This study was financially supported by the National Natural Science Foundation of China (Grant No. 32401600) and the National Key Research and Development Program of China (2016YFD0600106).

Author contributions

C.W. conceived and directed the research. M.Z. performed the overall data analysis. M.Z., Y.W., K.L.P.T., Y.C., X.L., and Y.L. constructed the overexpression vector and performed the experiments. M.Z. and C.W. wrote and revised the manuscript. All authors revised the manuscript. All authors read and approved the final manuscript.

Data availability

Data supporting the results are available in the article and its supplementary data.

Conflicts of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Supplementary material

Supplementary material is available at Horticulture Research online.

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