The study of the so-called unculturable bacteria is still considered a challenging task. However, given recent improvements in the sensitivity of culture-free approaches, the identification and characterization of such microbes in complex biological samples is now possible. In this chapter we report how endobacteria thriving inside arbuscular mycorrhizal fungi (AMF), which are themselves obligate biotrophs of plants, can be studied using a combination of in vitro culture, molecular biology, and microscopy techniques.
Keywords: Arbuscular mycorrhizal fungi; Bacterial enrichment; Candidatus Glomeribacter gigasporarum; Endobacteria; Fluorescent in situ hybridization; Mollicutes-related endobacteria; Real-time quantitative PCR; Transmission electron microscopy.