Methyl jasmonate induces triterpenoid biosynthesis in Inonotus baumii

In this work, methyl jasmonate (MeJA), as an exogenous elicitor, was used to investigate the feasibility of enhancing triterpenoid biosynthesis in Inonotus baumii. The results showed that the appropriate concentration of MeJA to be added was 150 mu mol/L, and the triterpenoid yield was 12.61 mg/g dry weight (DW), which was 4.05-fold higher than that in the control with water. Moreover, quantitative real-time polymerase chain reaction was performed to measure the transcript levels of several genes in the triterpenoid pathway, including those encoding hydroxy-3methylglutaryl-Coenzyme A synthase (hmgs), hydroxy-3-methylglutaryl-Coenzyme A reductase (hmgr), farnesyl pyrophosphate synthase (fpps), squalene synthase (sqs), squalene epoxidase (se) and lanosterol synthase (ls). The results demonstrated that these genes were mostly up-regulated by MeJA, although the levels of induction differed. For hmgs, hmgr, fpps and se, the highest transcript levels were at 150 mmol/L MeJA, and were approximately 3.0, 2.5, 2.0 and 2.0-fold higher than those in the control, respectively. However, the sqs and ls genes appeared to be repressed by MeJA. To the best of our knowledge, this is the first time to assess the use of MeJA to elicit triterpenoid biosynthesis in I. baumii, and the results indicated that MeJA was indeed a potent inducer of triterpenoid biosynthesis.