Involvement of CjMDR1, a plant multidrug-resistance-type ATP-binding cassette protein, in alkaloid transport in Coptis japonica.

摘要: Alkaloids comprise one of the largest groups plant secondary metabolites. Berberine, a benzylisoquinoline alkaloid, is preferentially accumulated in rhizome Coptis japonica, ranunculaceous plant, whereas gene expression for berberine biosynthetic enzymes has been observed specifically root tissues, which suggests that synthesized transported to rhizome, where there high accumulation. We recently isolated cDNA encoding multidrug-resistance protein (MDR)-type ATP-binding cassette (ABC) transporter (Cjmdr1) from berberine-producing cultured C. japonica cells, highly expressed rhizome. Functional analysis Cjmdr1 by using Xenopus oocyte system showed CjMDR1 an inward direction, resulting higher accumulation Cjmdr1-injected oocytes than control. Typical inhibitors ABC proteins, such as vanadate, nifedipine, and glibenclamide, well ATP depletion, clearly inhibited this CjMDR1-dependent uptake, suggesting functioned transporter. Conventional membrane separation methods was localized plasma cells. In situ hybridization indicated mRNA xylem tissues These findings strongly suggest involved translocation