Improved accumulation of ajmalicine and tetrahydroalstonine in Catharanthus cells expressing an ABC transporter.
ABSTRACT The biosynthetic pathway of monoterpenoid indole alkaloids in Catharanthus roseus is located throughout various membranes at both the cellular and intercellular levels. ATP-binding cassette (ABC) transporters are known to export vincristine and vinblastine from human cancer cells. It has recently been shown that ABC transporters are also involved in the transport of various monoterpenoid alkaloids in Catharanthus roseus cells. Over-expression of an ABC transporter in this plant might therefore affect the regulation of the alkaloid biosynthetic pathway. CjMDR1, an ABC transporter gene originally isolated from Coptis japonica, was expressed in Catharanthus roseus cell cultures. Cells showing a positive PCR signal of the transgene in both cDNA and genomic DNA samples were subject to transport studies using selected substrates. Unexpectedly, transport of the isoquinoline alkaloid berberine, the main substrate of CjMDR1 transporter in Coptis japonica, was not affected as compared with control and wild-type Catharanthus cells. On the other hand, the endogenous alkaloids ajmalicine and tetrahydroalstonine were accumulated significantly more in Catharanthus roseus cells expressing CjMDR1 in comparison with control lines after feeding these alkaloids.
- SourceAvailable from: Zahid Hameed Siddiqui[Show abstract] [Hide abstract]
ABSTRACT: Catharanthus roseus (L.) G. Don. is a well known medicinal plant. It produces several phyto-compounds many of which show anticancerous properties. The yields of these compounds are however, very low. In this present article, the current development of secondary metabolite synthesis in C. roseus involving biotechnology has been reviewed keeping in mind the various basic fac-tors that influence yield. The importance of cell culture, the role of culturing conditions and other approaches aiming at higher production of alkaloids have been discussed. The genes encoding important enzymes, proteomics, expressed sequence tag and transcription factors in relation to alka-loid yield have also been summarized in order to under-stand the regulatory mechanisms of C. roseus.· 1.67 Impact Factor
- 12/2013: pages 325–384; , ISBN: Print ISBN: 978-1-4665-8525-6; eBook ISBN: 978-1-4665-8531-7
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ABSTRACT: In order to improve the production of the anticancer dimeric indole alkaloids in Catharanthuse roseus, much research has been dedicated to culturing cell lines, hairy roots, and efforts to elucidate the regulation of the monoterpenoid indole alkaloid (MIA) biosynthesis. In this study, the ORCA3 (Octadecanoid-derivative Responsive Catharanthus AP2-domain) gene alone or integrated with the G10H (geraniol 10-hydroxylase) gene were first introduced into C. roseus plants. Transgenic C. roseus plants overexpressing ORCA3 alone (OR lines), or co-overexpressing G10H and ORCA3 (GO lines) were obtained by genetic modification. ORCA3 overexpression induced an increase of AS, TDC, STR and D4H transcripts but did not affect CRMYC2 and G10H transcription. G10H transcripts showed a significant increase under G10H and ORCA3 co-overexpression. ORCA3 and G10H overexpression significantly increased the accumulation of strictosidine, vindoline, catharanthine and ajmalicine but had limited effects on anhydrovinblastine and vinblastine levels. NMR-based metabolomics confirmed the higher accumulation of monomeric indole alkaloids in OR and GO lines. Multivariate data analysis of (1)H NMR spectra showed change of amino acid, organic acid, sugar and phenylpropanoid levels in both OR and GO lines compared to the controls. The result indicated that enhancement of MIA biosynthesis by ORCA3 and G10H overexpression might affect other metabolic pathways in the plant metabolism of C. roseus.PLoS ONE 01/2012; 7(8):e43038. · 3.73 Impact Factor