TY - JOUR A1 - Mikaelyan, A. A1 - Thompson, C. L. A1 - Meuser, K. A1 - Zheng, H. A1 - Rani, P. A1 - Plarre, Rüdiger A1 - Brune, A. T1 - High-resolution phylogenetic analysis of Endomicrobia reveals multiple acquisitions of endosymbiotic lineages by termite gut flagellates T2 - Environmental Microbiology Reports N2 - Bacteria of the class Endomicrobia form a deepbranching clade in the Elusimicrobia phylum. They are found almost exclusively in the intestinal tract of animals and are particularly abundant in many termites, where they reside as intracellular symbionts in the cellulolytic gut flagellates. Although small populations of putatively free-living lineages have been detected in faunated and flagellate-free hosts, the evolutionary origin of the endosymbionts is obscured by the limited amount of phylogenetic information provided by the 16S rRNA gene fragment amplified with Endomicrobia-specific primers. Here, we present a robust phylogenetic framework based on the nearfull-length 16S–23S rRNA gene region of a diverse set of Endomicrobia from termites and cockroaches, which also allowed us to classify the shorter reads from previous studies. Our data revealed that endosymbionts arose independently at least four times from different free-living lineages, which were already present in ancestral cockroaches but became associated with their respective hosts long after the digestive symbiosis between termites and flagellates had been established. Pyrotag sequencing revealed that the proportion of putatively free-living lineages increased, when all flagellates and their symbionts were removed from the gut of lower termites by starvation, starch feeding or hyperbaric oxygen, but results varied between different methods. KW - Endosymbionts KW - Evolution KW - Termites PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/42707 AN - OPUS4-42707 VL - 9 IS - 5 SP - 477 EP - 483 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany