Comparative Analysis of Terpenoids in in vitro Culture Media of Metabolically Engineered Transgenic and Wild Type Spearmint (Mentha spicata L.)

Abstract

IPP isomerase (Iso) and Limonene synthase (Limo) are important enzymes in terpenoids biosynthesis pathway. The wild type and each metabolically engineered (Iso and Limo) transgenic spearmint (Mentha spicata Linne) plants were compared for their growth patterns and the contents of essential oil in in vitro culture media. The profile of terpenoid metabolites was obtained from the essential oil of the metabolically engineered transgenic spearmint, which was extracted using a modified SDE method, by GC-MS analysis. The growth of wild spearmint was more profuse in B5 culture medium than in other media. Significant differences in leaf and root growth patterns were observed between metabolically engineered transgenic and wild type spearmint plants. The leaves of the transgenic spearmint plants were slightly elongated but were dramatically narrower than those of wild type spearmints. The content of essential oil of transgenic spearmint was different slightly depending on the target terpenoid genes. The content of essential oils in Limo transgenic plants was higher than that of Iso, except for transgenic plant in B5 medium. The transgenic spearmint produced more terpenoids than the wild type. Iso spearmint extracts showed eleven terpenoids and a phenylpropane, while Limo spearmint extracts contained nine terpenoids. However, extracts from the wild type showed the presence of only four terpenoids.