PIN2-mediated polar auxin transport regulation of root gravitropism in Arabidopsis thaliana

Auxin efflux carrier PIN2,PIN2-mediated polar auxin transport(PAT) and induced auxin synthesis effects on auxin nonsymmetric distribution and gravity response were examined in Arabidopsis roots.It was showed that mutated pin2,endogenously induced IAA and inhibition of PAT with NPA or TIBA severely impaired auxin nonsymmetric distribution and in turn inhibited root gravity response,indicated that PIN2-mediated PAT could regulate root gravity response through modulating auxin nonsymmetric distribution in the root tip.These findings would be helpful to understand the molecular mechanisms underlying auxin regulation of root gravitropism in plants.