Enhanced resveratrol accumulation in rolB transgenic cultures of Vitis amurensis correlates with unusual changes in CDPK gene expression

SummaryIt has been established that transformation of Vitis amurensis callus culture with the plant oncogene rolB of Agrobacterium rhizogenes results in a high level of resveratrol production in the transformed culture. In the present report, we investigated two rolB transgenic V. amurensis cell cultures with different levels of rolB expression and resveratrol production. We examined whether the calcium ion flux and later steps of the calcium-mediated signal transduction pathway play a role in resveratrol biosynthesis in the rolB transgenic cultures. It has been shown that the calcium channel blockers, LaCl3, verapamil, and niflumic acid, significantly reduced the accumulation of resveratrol in the rolB transgenic cultures. The number of the calcium-dependent protein kinase (CDPK) transcript variants and abundance of some of the transcripts were considerably altered in the rolB transgenic cell cultures, as revealed by frequency analysis of RT-PCR products and real-time PCR. Some unusual CDPK transcripts with deletions and insertions in the kinase domain were isolated from cDNA probes of rolB-transformed cells. These results suggest that active resveratrol biosynthesis in rolB transgenic cultures of V. amurensis is Ca2+ dependent. We propose that the rolB gene has an important role in regulation of calcium-dependent transduction pathways in transformed cells.