An efficient procedure has been developed for callus induction and cell suspension cultures of C. saxicola for the first time. Explant selection was carried out among leaf, stem and root to select a suitable type of explants capable of higher callus formation. Leaf explants thus selected showed maximum response to callus induction (67.1%). Modified B5 medium supplemented with 0.5 mg l−1 2,4-D plus 2 mg l−1 BA was the most favorable medium for callus formation with the highest induction rate (94.8%) and greatest fresh weight of callus (1.7 g per explant). Cell suspension cultures were established by transferring 2-8 g fresh callus to 80 ml liquid B5 medium. An inoculum size of 8 g produced the greatest biomass accumulation, dehydrocavidine and berberine productions, which was 13.1 g l−1, 8.0 mg l−1 and 4.1 mg l−1, respectively. In response to various sucrose concentrations from 10 g l−1 to 80 g l−1, cultures with 60 g sucrose l−1 not only produced the highest dry biomass (18.5 g l−1) but also the highest formation of dehydrocavidine (11.6 mg l−1) and berberine (7.6 mg l−1). These prepared cell suspension cultures provided a useful material for further regulation of alkaloid biosynthesis and for enhanced production of valuable alkaloids on a large scale.
Enhanced Production of hCTLA4Ig by Suppressing Cell Death in Transgenic Rice Cell Suspension Cultures