Synergistic Effect of Elicitors in Enhancement of Ganoderic Acid Production: Optimization and Gene Expression Studies

Ganoderma lucidum is one of the most well-known fungi, and has many applications in medicine. Ganoderic acid is among the valuable secondary metabolites of Ganoderma lucidum, and responsible for the inhibition of the tumor cell growth and cancer treatment. Application of ganoderic acid has been limited because of low yields of its production from Ganoderma lucidum. The present study aims to investigate the synergistic effect of elicitors including methyl jasmonate and aspirin on the production of ganoderic acid derived from Ganoderma lucidum mushroom in a shaken flasks using response surface methodology. The results showed that the optimal dose of methyl jasmonate and asprin significantly impacts on the amount of ganoderic acid production as a response (p<0.05). The proposed model predicted the maximum ganoderic acid production as 0.085 mgml-1 in which the optimal concentrations obtained for methyl jasmonate and asprin were 250 mM and 4.4 mM, respectively. Also the influence of ganoderic acid production on the expression of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase and squalene synthase (two important metabolic pathway genes in ganoderic acid) was investigated, and the results showed that these genes’ expression has increased by 10 and 11 folds, respectively.