Identification of gene markers to predict proanthocyanidins biosynthesis in cell culture of Croton lechleri

Croton lechleri Müll. Arg. is a traditional medicinal tree growing in South America, which produces a deep red sap known as Dragon’s Blood Sap (DBS) used for its many therapeutic benefits. DBS bioactivity is mainly due to the high content of proanthocyanidins (PAs), important plant secondary metabolites involved in plant defence, but also utilised as antioxidant for human health. Since the process to directly obtain DBS from the C. lechleri tree is expensive, time-consuming and strongly dependent on the environmental conditions, the use of plant cell cultures for DBS production seems to represent a suitable alternative. The aptitude of plant cell cultures to synthesize specific secondary metabolites can be elicited by different types of abiotic stresses. In this study, the C. lechleri main genes putatively involved in the PAs biosynthetic pathway were identified and their expression was evaluated in both calli in solid medium and cell culture suspensions to identify the most suitable predictive gene markers for PAs biosynthesis. C. lechleri cell cultures were grown and elicited by N-starvation to induce the production of PAs and were then monitored by assessing the expression of previously identified gene markers, by quantifying the content of PAs and measuring few phenotypical parameters. The results show a new perspective on how PA gene transcript abundance could be used to predict the biosynthesis of useful secondary metabolites in plant cell cultures and to speed up the screening of putative elicitors.