Microbial communities of bulk and Eschscholzia californica rhizosphere soils at two altitudes in Central Chile

Abstract

Despite several reports point out a rhizosphere effect shaping soil microbial communities and others an effect of altitude on plant phenotypic features, currently little is known about the impact of elevational patterns on the diversity of soil microbial communities. In this study, diversity of soil microbial communities was assessed in samples derived of bulk and rhizosphere soils associated to Californian poppy (Eschscholzia californica Cham.) populations at 1000 and 2000 m.a.s.l in Central Chile. E. californica, a native plant of North America, is considered a successful invader in Mediterranean ecosystems worldwide but its effect on diversity of soil microbial communities is yet unknown. Microbial diversity was evaluated at genetic level through T-RFLP (terminal restriction fragment length polymorphisms) using bacterial, archaeal and fungal molecular markers, and at metabolic level using CLPP (community-level physiological profiles). At genetic level, microbial diversities of bulk and rhizosphere soils at lower altitude were similar, although at higher altitude microbial diversity of both types of soils was different, suggesting a plant filtering effect more notorious at higher altitude. At metabolic level, microbial diversity of rhizosphere soils were similar independently of the altitude, suggesting a plant filtering effect that exceeds the altitude effect observed in the case of the bulk soil.