Abstract: It has been known that auxin plays an important role in regulating fruit development. The
transcription factors ARF and repressor protein Aux/IAA were the key factors in auxin signal transduction
system，both of them are involved in regulating physiological activities at the transcriptional level. To
explore the role of auxin in regulating the expression of the target gene during peach fruit development，the
full-length of the cDNA sequences of the six related genes were isolated and analyzed by bioinformatics.
One of them was PpARF1 selected from ARF family and the other five were PpIAA3，PpIAA9，PpIAA17，
PpIAA26 and PpIAA29 selected from Aux/IAA family. The relative expression levels in mesocarp and seed of peach fruit at different developmental stages were also detected by quantitative real-time PCR. The
results showed that：The number of the base pairs of the six genes were 2 037，594，1 194，618，384 and
723 bp，which encoded six proteins containing 678，197，397，205，127 and 240 amino acids respectively.
The sequence of PpARF1 amino acid shares 90.56% homology with FvARF1（XP_004300014.1）in
Fragaria vesca；Homology of the five proteins belongs to the PpIAA family was very low，only 23.77%.
The expression of PpIAA3 and PpIAA17 were significantly increased in mesocarp at the 52 days after full
flowering（hard core period）；The expression of PpIAA26，PpIAA29 and PpARF1 in seed also increased
significantly during that period. The results suggested that auxin might play an important role in regulating
development of peach fruit at hard core stage.

Key words: Prunus persica, ARF, Aux/IAA, cloning, expression analysis