Two B-type ATP-binding cassette (ABC) transporters localize to the plasma membrane in <i>Thalictrum minus</i>

Abstract

Alkaloids play important roles in plant defenses against herbivores and some alkaloids have medicinal uses. Medicinal alkaloids can be purified from plant tissues or produced axenically in cell culture systems. In culture, cells generally accumulate these toxic metabolites in the vacuole; however, treatment with benzyladenine (BA) induces cultured Thalictrum minus cells to produce the isoquinoline alkaloid berberine, which they release into the medium. A previous biochemical analysis suggested that B-type ATP-binding cassette (ABC) transporters participate in berberine efflux from cultured T. minus cells. In this study, we isolated full-length cDNAs of two novel B-type ABC transporter genes from T. minus, Tmabcb1 and Tmabcb2. The encoded transporters show significant amino acid sequence identity to the Coptis japonica berberine transporters CjABCB1 and CjABCB2. Real-time quantitative reverse transcription PCR analyses showed that BA induces an increase in Tmabcb1 and Tmabcb2 mRNA levels in cultured cells. Membrane separation and immunoblot analyses indicated that these proteins localize to the plasma membrane in T. minus cells. These data suggest that TmABCB1 and TmABCB2 participate in berberine transport in T. minus cells.

Genome-wide transcriptome profiling of Gossypium spp. roots during early growth after infection with Rotylenchulus reniformis

“…Plant ATP binding cassette (ABC) transporters move various substrates, using energy obtained by ATP hydrolysis, and are involved in several physiological functions, including detoxification of xenobiotics in addition to transport of hormones and secondary metabolites (Verrier et al, 2008;Yazaki et al, 2009;Kang et al, 2011;Shoji, 2014;Shitan et al, 2015). They tend to also accumulate in high concentrations in root tissue (Shitan et al, 2015) compared to leaf or stem tissue. The DEG annotations GO name F: protein serine/threonine kinase activity refers to a receptor that interacts with other proteins.…”