Effects of Elicitors on Tropane Alkaloids and Gene Expression in Atropa baetica Transgenic Hairy Roots

Elicitation of transgenic Atropa baetica overexpressing the h6h gene with salicylic acid (SA), acetylsalicylic acid (ASA), or methyl jasmonate (MeJ) was conducted to boost tropane alkaloid yields. Scopolamine (1) amounts increased after treatment with ASA and MeJ, but not with SA. The highest enhancement of 1 was achieved with MeJ followed by ASA dissolved in EtOH. Transcriptomic analyses showed a direct relationship between content of 1 and gene expressions; the engineered h6h gene and other biosynthetic genes were stimulated. ASA dissolved in EtOH showed a high h6h gene expression, increasing 25-fold and 5-fold compared to controls; tr-I also displayed a 5-fold increase. The controls to which EtOH was added showed a 5-fold increase in h6h gene expression and 125-fold for pint, demonstrating that EtOH also functioned as an enhancer of 1. MeJ was the best elicitor, displaying a 25-fold increase in h6h expression level, not affecting the expression of the other three genes analyzed, and it appears to possibly stimulate the phenylpropanoids branch of the tropane alkaloid pathway.