The ATP binding cassette transporter, VmTPT2/VmABCG1, is involved in export of the monoterpenoid indole alkaloid, vincamine in Vinca minor leaves

Abstract

Vinca minor is a herbaceous plant from the Apocynaceae family known to produce over 50 monoterpene indole alkaloids (MIAs). These include several biologically active MIAs that have a range of pharmaceutical activities. The present study shows that the MIAs, vincamine, akuammicine, minovincinine, lochnericine and vincadifformine tend to be secreted on V. minor leaf surfaces. A secretion mechanism of MIAs, previously described for Catharanthus roseus, appears to be mediated by a member (CrTPT2) of the pleiotropic drug resistance ABC transporter subfamily. The molecular cloning of an MIA transporter (VmTPT2/VmABCG1) that is predominantly expressed in V. minor leaves was functionally characterized in yeast and established it as an MIA efflux transporter. The similar function of VmTPT2/VmABCG1 to CrTPT2 increases the likelihood that this MIA transporter family may have co-evolved within members of Apocynaceae family to secrete selected MIAs and to regulate leaf MIA surface chemistry.

Keywords: ABC transporter; Apocynaceae; Monoterpene indole alkaloid; Pleiotropic drug resistance (PDR); Vinca minor; Vincadifformine; Vincamine.