Abstract
The growth hormone export PIN-FORMED (PIN) is an important carrier for regulating the polar transport of plant growth hormones and plays an important role in plant growth and development. However, little is known about the characteristics and functions of PINs in potatoes. In this study, 10 PIN members were identified from potatoes and named StPIN1, StPIN2, StPIN3, StPIN4, StPIN5, StPIN6, StPIN7, StPIN8, StPIN9, and StPIN10 according to their positions in the potato chromosome In addition, the expression of 10 StPINs was analyzed by qRT-PCR during potato root development. The results showed that the StPIN4 gene plays an important regulatory role in potato root development, and its tissue expression varied greatly. Several cis-regulatory elements related to growth factors were also detected in the promoter region of the StPIN gene. The transgenic overexpressing StPIN4 in potato showed suppressed growth in root length and lateral root number, and StPIN4-interfering plants showed the opposite. These results suggested that StPIN4 plays a key role in the regulation of the potato root architecture.