Genetic transformation of the tropical vine Pentalinon andrieuxii (Apocynaceae) via Agrobacterium rhizogenes produces plants with an increased capacity of terpenoid production

Abstract

Genetic modification using Agrobacterium rhizogenes has been an important biotechnological tool for the improvement of secondary metabolite production in plant species over the past four decades. The tropical vine Pentalinon andrieuxii, a native plant from the Yucatan Peninsula, is known to produce the triterpene betulinic acid and the novel tri-nor-sesquiterpene urechitol A and is used in the Mayan traditional medicine to treat leishmaniasis-derived lesions. Agrobacterium rhizogenes strain ATCC 15834 was used to infect leaf and hypocotyl explants of P. andrieuxii to generate 14 transformed plant lines with increased production of the terpenoids betulinic acid and urechitol A. Insertion of the transgenes was confirmed through PCR amplification of the rolA, rolB, and rolC genes. Betulinic acid and urechitol A were detected and quantified using standardized high-performance liquid chromatography and gas chromatography analyses, respectively. A significant increase in the terpenoid content was observed in some of the transgenic plants with up to 11.37 and 3.35 times more betulinic acid and urechitol A, respectively, when compared with the wild-type control. These new transgenic lines are promising tools to further the studies and knowledge about the biosynthesis of terpenoids in P. andrieuxii, especially regarding the biosynthetic origin of the rare urechitols.