The isolation and characterization of endophytic microorganisms from <i>Hyptis marrubioides</i> Epling roots

Abstract

Endophytic microorganisms asymptomatically colonize healthy plant tissues and may be related to the plant's resistance to attack by pathogens or even to the synthesis of secondary metabolites. The present study was aimed at isolating and characterizing endophytic strains from the root system of Hyptis marrubioides. Coarse and fine root fragments were collected for diaphanization and surface disinfection to isolate endophytes. After 10 days of incubation, we obtained the colonization rate (CR) of the fragments and the endophytic were purified and maintained in culture medium. The bacteria were partially characterized using Gram stain and a catalase test. Fungi were identified by distinguishing between reproductive structures using a microculture technique. While observing diaphanized root fragments, we found arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi in the fine and coarse roots of H. marrubioides. The endophytic CR was more significant in coarse root fragments. In both types of roots, the percentage of bacteria was higher than the percentage of fungi. Gram positive and catalase-positive bacteria accounted for the majority of bacterial isolates, which were predominantly bacilli. Of all the fungal isolates, the majority had sporulating mycelium, which mainly consisted of fungi from the genus Penicillium, Fusarium, Trichoderma and Papulaspora.

Keywords: Bacteria, fungus, Lamiaceae, root system