OsMADS27 regulates the root development in a NO3--Dependent manner and modulates the salt tolerance in rice (Oryza sativa L.).

OsMADS27 is one of the ANR1-like homologues in rice, whreas its functions in plant growth and development as well as the abiotic stress responses remain unclear. Here we investigated the roles of OsMADS27 in the root development in response to NO3- availability. Constitutive expression of OsMADS27 significantly inhibited the elongation of primary root (PR), but enhanced lateral root (LR) formation in a NO3--dependent manner. Furthermore, OsMADS27 overexpression promoted NO3- accumulation as well as the expression of NO3- transporter genes. ABA is reported to play an important role in mediating the effects of NO3- on the root development, thus it is supposed that OsMADS27 might regulate the root growth and development by ABA pathway. The root growth and development in OsMADS27 overexpression lines was shown to be more sensitive to exogenous ABA than wild type. Moreover, under NO3- conditions, higher levels of ABA accumulates in OsMADS27 overexpression plants. Yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays showed that OsMADS27 physically interacts with ABA-INSENSITIVE5 (OsABI5) via DELLA protein OsSLR1. More importantly, OsMADS27 overexpression could enhance the salt tolerance. Taken together, our findings suggested that OsMADS27 is an important regulator controlling the root system development and adaption to osmotic stress in rice.