Mycorrhizal influence on the growth and bioactive compounds composition of two medicinal plants: Mikania glomerata Spreng. and Mikania laevigata Sch. Bip. ex Baker (Asteraceae)

Abstract

Arbuscular mycorrhiza (AM) is one of the most ubiquitous plant symbioses, contributing to overall plant performance through nutritional and non-nutritional benefits. As result of mycorrhization, the active compounds derived from plants may be altered both quantitatively and qualitatively. The species Mikania glomerata Spreng. and Mikania laevigata Sch. Bip. ex Baker popularly called guaco, are widely distributed in the Americas and commonly cultivated as a popular remedy for respiratory diseases. The aim of this study was to evaluate the response of M. laevigata and M. glomerata to the inoculation of the AM fungus Rhizophagus irregularis (Blaszk., Wubet, Renker & Buscot) in terms of biomass and bioactive compound accumulation. Both species showed high colonization rates, which, in general, resulted in discrete effects on biomass production, whereas no growth-promoting effect was observed in M. glomerata; AM significantly increased foliar biomass production in M. laevigata. AM increased foliar P, K, Cu, Zn, and B concentrations in M. glomerata, and in M. laevigata, AM caused higher foliar Mg and lower Fe contents. Mycorrhization altered the contents of the bioactive compounds analyzed in a different manner for each species. Leaves of AM M. laevigata plants showed contents of the diterpene kaurenoic acid four times higher, suggesting an induction of terpenoid biosynthetic pathways. In M. glomerata, AM symbiosis reduced the contents of tricaffeoylquinic acids. This is, we believe, the first report showing the response of these species to mycorrhization and its influence on growth, mineral nutrition, and foliar contents of chemicals with bioactive properties, which are of increasing interest in pharmacological and food industries.