Yield enhancement strategies for the production of picroliv from hairy root culture ofPicrorhiza kurroaRoyle ex Benth.

Abstract

Fast-growing hairy root cultures of Picrorhiza kurroa induced by Agrobacterium rhizogenes offers a potential production system for iridoid glycosides. In present study we have investigated the effects of various nutrient medium formulations viz B5, MS, WP and NN, and sucrose concentrations (1-8%) on the biomass and glycoside production of selected clone (14-P) of P. kurroa hairy root. Full strength B5 medium was found to be most suitable for maximum biomass yield on the 40th day of culture (GI D 32.72 § 0.44) followed by the NN medium of the same strength (GI D 22.9 § 0.43). Secondary metabolite production was 1.1 and 1.3 times higher in half strength B5 medium respectively in comparison to MS medium. Maximum biomass accumulation along with the maximum picroliv content was achieved with 4% sucrose concentration in basal medium. RT vitamin and Thiamine-HCl effected the growth and secondary metabolite production of hairy roots growing on MS medium but did not show any effect on other media. The pH of the medium played significant role in growth and secondary metabolite production and was found to be highest at pH 6.0 while lowest at pH 3.0 and pH 8.0. To enhance the production of biomass and Picroliv 5 liter working capacity bioreactor was used, 27-fold (324 g FW) higher growth was observed in bioreactor than shake flask and secondary metabolite production was similarly enhanced.

Growth of Leonurus sibiricus L. roots with over-expression of AtPAP1 transcriptional factor in closed bioreactor, production of bioactive phenolic compounds and evaluation of their biological activity

“…Similarly, Verma et al report greater secondary metabolite production in a 5 L bioreactor than a shake flask (Verma et al, 2015). Conversely, Kuzma et al note that diterpene production was more efficient in shake flask root culture than the 5 L bioreactor (Kuzma et al, 2017).…”

Enhanced Secondary Metabolite Production in Hairy Root Cultures Through Biotic and Abiotic Elicitors

“…Temperature around 25°C is usually given for culturing of hairy roots [8]. Fluctuations in temperature such as low temperatures (cold stress) or high temperatures (heat stress) also enhance the secondary metabolite production as temperature affects the overall metabolic activity of the hairy roots.…”

“…Hairy root culture (HRC), however, plays important functions in the enhancement of secondary metabolite production in plants, as it provides controlled conditions for the plant propagation and a very good substitute for the whole plant material extraction [6][7][8][9][10][11], since tissue-specific compounds can easily be extracted by the plant root culture [8,12]. Besides, the higher proliferation rates, controlled conditions, shorter life cycles, etc.…”

“…Besides, the higher proliferation rates, controlled conditions, shorter life cycles, etc. are some other advantages [8]. A gram-negative bacterium Agrobacterium rhizogenes dwells in soil, which belongs to the family Rhizobiaceae, and a wide range of plant species can get infected by it.…”

“…In the future, the hairy root-based production approach may become a common method, allowing for the commercial production of plenty of useful products [27]. The productivities of hairy root cultures have already been reported to be enhanced through adopting strategies such as selecting and screening of high yielding line, culture media composition optimization, utilization of bioreactors, metabolic engineering, precursor feeding, and lastly biotransformation, etc., and have also been tested to estimate their efficiency in secondary metabolite production enhancement [8,26].…”