A Putative Auxin Efflux Carrier, REH1 Functional Analysis In Rice (Oryza Sativa L.)

Auxin is a small molecule that has long been implicated in a confounding number of processes in plants. It is thought to be synthesized in young apical tissues and to be transported downward to the maturing stem and to the roots by a polar transport system that can be blocked with specific inhibitors. The polar auxin transport is required for important growth and developmental processes in plants, including the regulation of branching processes in shoots and roots. Current models suggest that asymmetrical localization of auxin influx and efflux carriers within the plasma membrane control the establishment of auxin gradients via facilitated transport REH1, a putative auxin efflux carrier PIN-FORMED1 family gene in rice, was identified in this study. REHl expressed in the vascular tissues and the root primordia. which was consistent with AtPIN1. The crown roots emergence delayed in the REHl RNA interfering plants, which could be phynocopied by NPA treatment and be rescued by NAA treatment. Additionally, abnormal expression of REH1 also affected tilling and broke the balance of shoot/root ratio. Taken together, these data suggested that REHl plays an important role in auxin-dependent crown roots emergence. tillering and the shoot/root ratio.