Optimization of Nutritive Factors in Culture Media for Growth and Tropane Alkaloid Production from Anisodus acutangulus Hairy Roots.

Anisodus acutangulus hairy roots were grown in N6 medium which was optimal for growth and alkaloid production. The cell biomass and alkaloid yield reached 2.7 g l-1 and 3.9 mg l-1 (dry weight) respectively in sucrose medium, higher than those obtained in other carbon source media. 90 mM nitrogen (NH4 +/NO3 – = 4:1) gave the highest cell yield (4.5 g l-1) and the maximum alkaloid production (9.9 mg l-1). The cell yield (4.1 g l-1) of hairy roots grown at pH 6.5 was 2 times higher than that at pH 4.5. However, the maximum alkaloid production (7.2 mg l-1) was yielded at pH 4.5.

Enhancement of camptothecin production in Camptotheca acuminata hairy roots by overexpressing ORCA3 gene.

Being a good anti-tumor drug, camptothecin (CPT) is a kind of modified monoterpene indole alkaloid firstly isolated from the deciduous Chinese happy tree with rapidly increasing clinical demand. Due to the great importance and low content of this compound, it is very important to improve CPT production by modern biotechnology. ORCA3 is a jasmonateresponsive APETALA2-domain transcript factor isolated from Catharanthus roseus, with strong ability to up-regulate expression of serveral key genes involved in TIA biosynthetic pathway. To investigate physiological function of ORCA3 gene in Camptotheca acuminata, the ORCA3 gene was transformed using Agrobacterium-mediated gene transfer technology. PCR analysis confirmed that the ORCA3 gene was integrated into the plant genome. HPLC showed that overexpression of ORCA3 in transgenic hairy root lines can effectively enhance the production of camptothecin with 1.5-fold compared with the control (1.12 mg/g dw). The results revealed that ORCA3 is an effective regulatory gene for improving metabolic flux in camptothecin biosynthetic pathway at the first time.

cDNA cloning and characterization of a mannose-binding lectin from Zingiber officinale Roscoe (ginger) rhizomes.

Using RNA extracted from Zingiber officinale rhizomes and primers designed according to the conservative regions of monocot mannose-binding lectins, the full-length cDNA of Z. officinale agglutinin (ZOA) was cloned by rapid amplification of cDNA ends (RACE). The full-length cDNA of zoa was 746 bp and contained a 510 bp open reading frame (ORF) encoding a lectin precursor of 169 amino acids with a signal peptide. ZOA was a mannose-binding lectin with three typical mannose-binding sites (QDNY). Semi-quantitative RT-PCR analysis revealed that zoa expressed in all the tested tissues of Z. officinale including leaf, root and rhizome, suggesting it to be a constitutively expressing form. ZOA protein was successfully expressed in Escherichia coli with the molecular weight expected. To our knowledge, this is the first mannose-binding lectin cDNA cloned from the family Zingiberaceae. Our results demonstrate that monocot mannose-binding lectins also occur within the family Zingiberaceae.

Isolation and characterization of a new mannose-binding lectin gene from Taxus media.

In this paper, we report the cloning and characterization of the first mannose-binding lectin gene from a gymnosperm plant species, Taxus media. The full-length cDNA of T. media agglutinin (TMA) consisted of 676 bp and contained a 432 bp open reading frame (ORF) encoding a 144 amino acid protein. Comparative analysis showed that TMA had high homology with many previously reported plant mannose-binding lectins and that tma encoded a precursor lectin with a 26-aa signal peptide. Molecular modelling revealed that TMA was a new mannosebinding lectin with three typical mannose-binding boxes like lectins from species of angiosperms. Tissue expression pattern analyses revealed that tma is expressed in a tissue-specific manner in leaves and stems, but not in fruits and roots. Phylogenetic tree analyses showed that TMA belonged to the structurally and evolutionarily closely related monocot mannose-binding lectin superfamily. This study provides useful information to understand the molecular evolution of plant lectins.