**5. Conclusions**

We identified a drought-induced WRKYII gene *ZmWRKY106* based on maize drought *de novo* transcriptome sequencing data (SRP144573). *ZmWRKY106* was only observed in the nucleus. The expression of *ZmWRKY106* was induced significantly by drought, high-temperature, and exogenous abscisic acid (ABA) treatments, but was induced weakly by salt. Further research revealed that overexpression of *ZmWRKY106* could improve tolerance to drought and heat in transgenic *Arabidopsis* by regulating stress-related genes through the ABA-signaling pathway, and could reduce the ROS content in transgenic lines by enhancing the activities of SOD, POD and CAT under drought stress. These results may provide a basis for understanding the functions of *ZmWRKY106* in abiotic stress response in maize.

**Supplementary Materials:** Supplementary materials can be found at http://www.mdpi.com/1422-0067/19/10/ 3046/s1.

**Author Contributions:** Conceptualization, C.-T.W., J.-N.R., and J.-F.Y.; methodology, C.-T.W., J.-N.R., and Y.-W.L.; validation, C.-T.W., J.-N.R., and Y.-W.L.; formal analysis, C.-T.W. and J.-N.R.; investigation, C.-T.W. and J.-N.R.; data, C.-T.W. and J.-N.R.; writing—original draft preparation, C.-.T.W. and J.-N.R.; writing—review and editing, Z.-S.X. and J.-D.F.; supervision, J.-F.Y. and Y.-W.L.; project administration, Z.-S.X. and J.-D.F.; funding acquisition, M.L. and D.Z.

**Funding:** This study was financially supported by the Funding Project for Beijing Advanced Innovation Center for Food Nutrition and Human Health, and the Open Research Fund Program of Beijing Key Lab of Plant Resource Research and Development, Beijing Technology and Business University.

**Acknowledgments:** We thank Li-Na Ning for critically reading the manuscript.

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