[S3-2] Microbial interactions of endobacteria coexisted within the filamentous fungus cells
A bacterium that is endogenous to the hyphal cells of the filamentous fungus Mortierella was found in agricultural soil. It was proposed that there is an endosymbiotic relationship between microorganisms in the filamentous fungus-endobacteria. Previous studies have suggested that certain filamentous fungi harbor different endogenous bacteria depending on their ecological characteristics. A total of 66 isolates of Mortierella, which found as the Burkholderiaceae-related endobacteria (BRE), were obtained newly. Molecular phylogenetic analysis based on the 16S rRNA gene of the detected BRE revealed that the BREs in the Glomeribacter-Mycoavidus clade were separated phylogenetically into three groups. A culturable endosymbiotic bacterium, Mycoavidus sp. strain B2-EB, present in the fungal host Mortierella parvispora E1425, was obtained successfully, and the complete genome sequence of strain B2-EB was carried out. Comparative genome analysis among the genus Mycoavidus strains indicated that the strain B2-EB are characterized by reduced genomes and metabolic dependence on the host, suggesting the decreased adaptability to the environment. In this symposium, we will also discuss the microbial interactions that is a symbiosis of filamentous fungi harboring BRE.