New intranuclear symbiotic bacteria from macronucleus ofParamecium putrinum—CandidatusGortzia yakutica

Holospora -like bacteria are obligate intracellular Alphaproteobacteria , inhabiting nuclei of Paramecium ciliates and other protists. Alphaproteobacteria have drawn significant attention, as both closest existing relatives of bacteria that gave rise to mitochondria, as well as a class of intracellular bacteria with numerous important pathogens. HLB clade includes two genera – Holospora (Hafkine 1980) and candidatus Gortzia (Boscaro 2013). These bacteria have a peculiar life cycle with two morphological forms, a strict specificity to the host species and the type of nucleus they inhabit. Here we describe a new species of HLB – candidatus Gortzia yakutica sp. nov., a symbiont from macronucleus of Paramecium putrinum , the first known HLB for this Paramecium species. The new symbiont shows morphological similarities with other HLB. The phylogenetic analysis of SSU rDNA gene places it into candidatus Gortzia clade.