BackgroundDeep rooting is an important factor affecting rice drought resistance. However, few genes have been identified to control this trait in rice. Previously, we identified several candidate genes by QTL mapping of the ratio of deep rooting and gene expression analysis in rice.ResultsIn the present work, we cloned one of these candidate genes,OsSAUR11, which encodes a small auxin-up RNA (SAUR) protein. Overexpression ofOsSAUR11significantly enhanced the ratio of deep rooting of transgenic rice, but knockout of this gene did not significantly affect deep rooting. The expression ofOsSAUR11in rice root was induced by auxin and drought, and OsSAUR11-GFP was localized both in the plasma membrane and cell nucleus. Through an electrophoretic mobility shift assay and gene expression analysis in transgenic rice, we found that the transcription factor OsbZIP62 can bind to the promoter ofOsSAUR11and promote its expression. A luciferase complementary test showed that OsSAUR11 interacts with the protein phosphatase OsPP36. Additionally, expression of several auxin synthesis and transport genes (e.g.,OsYUC5andOsPIN2) were down-regulated inOsSAUR11-overexpressing rice plants.ConclusionsThis study revealed a novel geneOsSAUR11positively regulates deep rooting in rice, which provides an empirical basis for future improvement of rice root architecture and drought resistance.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-023-04320-w.