Comparative investigation on the effect of Piriformospora indica mycelium extract and culture medium on phenolic compounds in Linum album hairy roots

Lignans are a large group of important phenolic compounds and synthesized by many plants such as Linaceae family. In this research, the effects of different concentrations of mycelium extract and culture medium of Piriformospora indica on the levels of phenolic compounds in L. album hairy roots were investigated. The amount of lariciresinol, pinoresinol, podophyllotoxin and 6-methoxy podophyllotoxin were also analyzed by HPLC. To study the fungal elicitors’ mechanism of action, phenylalanine ammonia-lyase (PAL) enzyme activity was investigated. Results showed that maximum amounts of podophyllotoxin and 6-methoxy podophyllotoxin were at 1 % (v/v) of fungal medium, 248.9 µg/g and 59.59 mg/g DW, respectively and the highest amounts of lariciresinol and pinoresinol respectively were seen at 1 and 0.5 % (v/v) of mycelium extract, 144.68 and 72.68 µg/g DW. Maximum amounts of total phenol, flavonoid and lignin were analyzed at 5 % (v/v) and flavonol at 1 % (v/v) fungal culture treatments which were 3.3, 4.6, 1.6 and 2.1 -fold greater than those of control. The activity of PAL enzyme was induced by mycelium extract and fungal medium, reaching a peak at 1 % and 5 % (v/v), respectively. Consider to these results, fungal culture medium was more effective than mycelium extract for stimulation of phenolic compound production.