DBC1, an allelic OsDRP2B gene, regulating plant height by controlling cell division in Oryza sativa L.

Plant height directly affects the lodging resistance and yield of rice, a staple food for almost half the world's population. To investigate the molecular mechanism of plant height development, a dwarf and brittle mutant dbc1 was obtained from the progeny of Ethylmethane sulfonate (EMS) treated indica restorer line Jinhui10. Cultivated in the paddy field, the dbc1 had a decreased plant height from the seedling stage through to maturity. All internodes of dbc1 were reduced in length at a highly significant level, compared with those of the wild type. However, paraffin sectioning showed that their cell sizes displayed no obvious difference. Additionally, the dbc1 developed more slowly than the wild type, having a developmental delay of 7 days. Cells at the root apical meristem (RAM) containing two nuclei were much more abundant in dbc1 compared to those of the wild type. The regulated gene of dbc1 was confirmed as encoding a dynamin-related protein 2B (OsDRP2B) by mapped-based cloning strategy. qPCR indicated that the expression of cell cycle related genes decreased in the mutant and was partially restored in DBC1-overexpressed plant. Gibberellin response assay showed that the dbc1 was less sensitive to exogenous GA(3), the endogenous bioactive GA(1) decreased significantly, and these results agreed with the qPCR analysis. The OsDRP2B/DBC1 was proposed to control plant height by regulating cell division, and the process was partially influenced by the gibberellin pathway.