The effect of medium compounds on hairy root induction in chicory (cichorium intybus l.) and enhancement of secondary metabolites

Chicory (Cichorium intybus L.) is an important medicinal plant from Asteraceae family; contain a number of valuable medicinal compounds. Hairy root induction by Agrobacterium rhizogenes are an effective method for production of secondary metabolites.

In this study, through first experiment, different concentrations of macro elements (0.5x, 1x, 1.5x, 2x, 2.5x and 3x concentrations of MS base medium) were investigated. In second experiment inoculation time was examined to establish an efficient transformation system for chicory. Molecular confirmation of transgenic hairy roots was done with PCR using gene-specific primers for rolB gene and also growth rate of hairy root lines obtained from different explants were investigated. Also the effect of hormonal elicitor and carbon source were studied in hairy roots growth.

The results show that maximum chicory hairy roots induction was observed by using 1x KNO3, 1.5x NH4NO3, 1x and 1.5x MgSO4, 1.5x CaCl2 and 0.5x KH2PO4 (45.66, 53.33, 46.66, 53.33 and 66.66). The highest phenolic content was obtained by using 1x KNO3, 2x NH4NO3, 1.5x MgSO4, 1.5x CaCl2 and 0.5x KH2PO4 (4.21, 4.33, 4.6, 4.58 and 4.84). Also 1.5x KNO3, 2x NH4NO3, 1x MgSO4, 1.5 CaCl2 and 0.5x KH2PO4showed maximum flavonoid content (17.25, 18.52, 17.22, 18.3, 17.96 mg g DW respectively).The observation confirmed that grow of hairy root lines were significantly different and Line C showed higher biomass (0.36 g). Also the results of experiments revealed that 1.5 mg l-1 NAA in combination with 3 and 4% sucrose were superior for highest fresh (1.96 and 1.72 g) weight.
 Conclusions

Hairy roots culture was developed as the innovative path for bulky production of secondary metabolites which find relevance in the pharmaceutical, food and flavor industries. The results indicated significant increases in hairy root induction and total metabolites content by ATCC15834 strain and 0.5x KH2PO4 co-culture MS medium.