Molecular cloning and functional characterization of MdPIN1 in apple

Auxin has been identified to play critical roles in regulating plant growth and development. The polar transport of auxin is regulated by auxin transporters. In the present study, an auxin efflux carrier gene MdPIN1 was cloned from Malus×domestic, Royal Gala, and introduced into wild-type Arabidopsis thaliana (Col-0). The transgenic plants exhibited the phenotype of inhibition of primary root (PR) elongation and increased lateral root (LR) number in compared with Col-0. Overexpression of MdPIN1 affected auxin transport, and enhanced phototropic responses and geotropism reaction, whereas had no significant difference in the auxin biosynthesis. These findings suggest that the MdPIN1 gene plays a vital role in auxin transport and root development.