Sequential influence of MeJA on pathways synthesizing indole alkaloids and phenolic compounds

Seeds of C. roseus were left to germinate in pots in the greenhouse of King Abdulaziz University, Jeddah, KSA complying with the institutional, national and international guidelines. No ethics approval was required for any aspect of this study. Pots contained sterilized soil : vermiculate at 1 : 1 and growing plantlets were watered with sterile ddH2O. Seedlings were grown for 4 weeks at 25°C with 16-h light periods, ~125 uE m-2sec-1 light intensity and ~70% humidity. Evaporated water was replaced daily. Then, 4-wk-old seedlings were watered with MeJA in two replicates at final concentration of 6 uM and leaf samples were collected after 6, 12 and 24 days. Concurrently, control seedlings were watered with the solvent DMSO at equivalent volume and leaf samples were collected in two replicates at the same time points. Flash-frozen similar-sized leaf samples were instantly crushed into a fine powder in a microcentrifuge tube and total RNAs were extracted and quantified. Then, RNAs were shipped to BGI, China, for deep sequencing.