3.4.3. Elicitation
Numerous studies reported enhanced taxol production using a wide range of elicitors such as salicylic acids, MeJA, coronatine. Salicylic acid (SA) has a vital role in the plant defense regulatory system. The interaction of plant to pathogen resulted in the accumulation of salicylic acid at the infection site, which triggers signals to the defense system (Pieterse and van Loon, 1999). Salicylic acid response leads to the production of the secondary metabolite, acting as a secondary metabolite elicitor (Dučaiová et al., 2013). Salicylic acid elicitation on the Taxus genus resulted in improved diterpene alkaloid production. In suspension cultures of Taxus chinensisinduction of 20mg/l, salicylic acid resulted in 1.5 mg/g DW taxol. Salicylic acid, in combination with mevastatin, an inhibitor of HMG-CoA, and increased intensified taxol production up to 1.6 mg/g DW (Wang et al., 2007). A low level of taxol production was also reported in suspension culture cells of hazelnut plant Corylus avellana L. with the use of salicylic acid as an elicitor enhancing taxol production. The amount of taxol produced is 50 mg/l in salicylic acid-treated cultures. Moreover, salicylic acid (50 mg l-1) and ultrasound treatment (40 kHz for 2, 3, 5, and 10 min) synergistically increased taxol production (0.7 mg l-1) 14 times higher than control cultures (0.05 mg l-1) (Rezaei et al., 2011). It has been reported that the inclusion of 200 µm of MeJA alone in a cell suspension culture of Taxus increased the taxane yield to 23.4 mg/l 20% of total taxol production using this plant (McElroy and Jennewein, 2018) (Table 2 ). The synergistic effect of MeJA with fructose at 100µm concentration resulted in 17.07 mg/l taxol production. While elicitation with MeJA along with another cyclodextrin increases 55 times higher taxol production in Taxus(Singh and Dwivedi, 2018) (Table 2 ).