Abstract: Adventitious roots form only at the proximal cut surface（PCS）but not at the distal cut surface（DCS）of mango cotyledon segments，it was suggested that polar auxin transport play important role in this process but the role of multi-drug-resistant/P-glycoprotein（MDR/PGP）in this rooting was unclear. In this study，two mango MDR/PGP genes，designated as MiPGP1 and MiPGP2，were isolated from the cotyledon of mango（Mangifera indica L.‘Yuexi 1’）using RT-PCR and RACE. The full-length cDNA of MiPGP1 and MiPGP2 were 4 650 and 4 107 bp，with the open reading frames of 4 092和3 851 bp，which encode two putative proteins of 1 363 and和1 289 amino acids，respectively. The genomic DNA sequences of MiPGP1 and MiPGP2 were 6 430 and 5 747 bp，with the lengths of 6 082 and 5 633 bp，respectively，from the start codon to the terminator codon. Phylogenetic tree analysis indicated that MiPGP1 and MiPGP2 belong to plant PGP1 group. Quantitative real-time PCR showed that MiPGP1 and MiPGP2 expressed in PCS（where adventitious root formed）or DCS（no adventitious root formed）throughout the adventitious root formation period. Meanwhile，the relative expression of MiPGP1 and MiPGP2 was low at 0 d，but which was significantly up-regulated from 6 h until adventitious root appeared at 10 d，and the relative expression was always higher in DCS than that of PCS. However，the relative expression of MiPGP2 was significantly up-regulated by the pre-treatment with indole-3-butyric acid（IBA）but not MiPGP1. Pre-treatment with 2,3,5-triiodobenzoic acid（TIBA）inhibited the relative expression of MiPGP1 and MiPGP2 at some time points. In additon，the results of MiPGP1 and MiPGP2 overexpression in Arabidopsis plants showed that there was a significant increasment in adventitious root quantity in MiPGP2 transgenic line in hypocotyl. In conclusion，MiPGP2 might play an important role during the adventitious root formation of mango cotyledon segments.

Key words: Mangifera indica, MiPGP1, MiPGP2, expression analysis, overexpression, Arabidopsis, adventitious root