A Novel AP2/ERF Transcription Factor, OsRPH1, Negatively Regulates Plant Height in Rice

Ziming Ma; Tao Wu; Kai Huang; Yong-Mei Jin; Zhao Li; Mojun Chen; Sokyong Yun; Hongjia Zhang; Xue Yang; Haoyuan Chen; Huijiao Bai; Lin Du; Shanshan Ju; Liping Guo; Mingdi Bian; Lanjuan Hu; Xinglin Du; Wenzhu Jiang

doi:10.3389/fpls.2020.00709

A Novel AP2/ERF Transcription Factor, OsRPH1, Negatively Regulates Plant Height in Rice

Front Plant Sci. 2020 May 27:11:709. doi: 10.3389/fpls.2020.00709. eCollection 2020.

Authors

Ziming Ma¹, Tao Wu¹, Kai Huang¹, Yong-Mei Jin², Zhao Li¹, Mojun Chen², Sokyong Yun³, Hongjia Zhang¹, Xue Yang¹, Haoyuan Chen¹, Huijiao Bai¹, Lin Du¹, Shanshan Ju¹, Liping Guo¹, Mingdi Bian¹, Lanjuan Hu¹, Xinglin Du¹, Wenzhu Jiang¹

Affiliations

¹ Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun, China.
² Jilin Academy of Agricultural Sciences, Changchun, China.
³ Kye Ung Sang College of Agriculture of Kim II Sung University, Pyongyang, North Korea.

Abstract

The APETALA 2/ethylene response factors (AP2/ERF) are widespread in the plant kingdom and play essential roles in regulating plant growth and development as well as defense responses. In this study, a novel rice AP2/ERF transcription factor gene, OsRPH1, was isolated and functionally characterized. OsRPH1 falls into group-IVa of the AP2/ERF family. OsRPH1 protein was found to be localized in the nucleus and possessed transcriptional activity. Overexpression of OsRPH1 resulted in a decrease in plant height and length of internode and leaf sheath as well as other abnormal characters in rice. The length of the second leaf sheath of OsRPH1-overexpressing (OE) plants recovered to that of Kitaake (non-transgenic recipient) in response to exogenous gibberellin A₃ (GA₃) application. The expression of GA biosynthesis genes (OsGA20ox1-OsGA20ox4, OsGA3ox1, and OsGA3ox2) was significantly downregulated, whereas that of GA inactivation genes (OsGA2ox7, OsGA2ox9, and OsGA2ox10) was significantly upregulated in OsRPH1-OE plants. Endogenous bioactive GA contents significantly decreased in OsRPH1-OE plants. OsRPH1 interacted with a blue light receptor, OsCRY1b, in a blue light-dependent manner. Taken together, our results demonstrate that OsRPH1 negatively regulates plant height and bioactive GA content by controlling the expression of GA metabolism genes in rice. OsRPH1 is involved in blue light inhibition of leaf sheath elongation by interacting with OsCRY1b.

Keywords: AP2/ERF transcription factor; OsCRY1b; OsPRH1; plant height; rice.