Abstract:

Fruits of Rosa roxburghii Tratt‘Guinong 5’were used to investigate the effects of divalent cations of Ca²⁺ and Cu²⁺ on expression of the genes involved in L-ascorbic acid（AsA）biosynthesis and accumulation using the methods of incubation in vitro. The results showed that exogenous Ca²⁺ had a positive role in promoting AsA accumulation，while Cu²⁺ accelerated AsA degradation during incubation. Quantitative real-time PCR analysis showed that the expression of GalLDH and GPP in L-galactose biosynthetic pathway and DHAR and MDHAR in recycling pathway upregulated sigificantly when fruit flesh tissues was incubated with Ca²⁺，indicating that this divalent cation took part in the regulation of gene transcription. Exogenous Cu²⁺ showed a slight exhibition of GalLDH and GGP expression but failed to down-regulate the expression of AAO or APX，which suggests that AsA degradation incubating Cu²⁺ occuerrd not primarily on the transcription level.

Key words: Rosa roxburghii, Ca2+, Cu2+, ascorbic acid, gene expression