Assessment of squalene synthase and beta-amyrin synthase gene expression in licorice roots treated with methyl jasmonate and salicylic acid using real-time qPCR

Expression of two key biosynthetic enzymes for terpenoid biosynthesis (squalene synthase and beta-amyrin synthase) was analyzed in licorice as a model organism. For two elicitors, methyl jasmonate (MeJa) and salicylic acid (SA), the roots of 65-day-old plantlets treated with a combination of various elicitor concentrations and treatment times were used for RNA extraction and reverse transcription to cDNA. A protocol for real-time quantitative PCR (RT-qPCR) analysis of these two genes was developed (relative approach) using 18S rRNA gene as an internal standard. Results showed that after 24 h of elicitation, transcripts of SQS gene were increased at all concentrations of the MeJa, but increased only at 0.1 and 1 mM of SA. For bAS gene, after 24 h of elicitation, transcripts were increased at 0.1, 1, and 2 mM of MeJa, while they were increased only at 0.1 and 1 mM SA. These results are discussed and showed that they are well in accordance with our previous results on glycyrrhizin accumulation in the roots.