Draft genome sequences of three Holospora species (Holospora obtusa, Holospora undulata, and Holospora elegans), endonuclear symbiotic bacteria of the ciliate Paramecium caudatum

We present draft genome sequences of three Holospora species, hosted by the ciliate Paramecium caudatum; that is, the macronucleus-specific H. obtusa and the micronucleus-specific H. undulata and H. elegans. We investigate functions of orthologous core genes conserved across the three Holospora species, which may be essential for the infection and survival in the host nucleus.