Chiang Mai Journal of Science

     A novel species, Gulbenkiania indica, was reported from a sulfur spring. During the proposal of this species, it was reported that it shared 99.0% 16S rRNA gene sequence similarity with the type strain of Gulbenkiania mobilis. Despite its high 16S rRNA gene sequence similarity, a 30% DNA-DNA hybridization value was reported, which was below the threshold for species delineation (70%). Although DNA-DNA hybridization was considered the gold standard for species delineation, but often prone to errors. In the present study, the taxonomic position of Gulbenkiania indica was re-evaluated by genome relatedness, phylogenetic and phylogenomic analysis. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between Gulbenkiania mobilis DSM 18507^T and Gulbenkiania indica DSM 17901^T was 99.2 and 93.7%, respectively, which was above the cutoff value (95–96%, ANI; 70%, dDDH) for species delineation. In phylogenetic (based on 16S rRNA gene sequence) and phylogenomic (based on 71 bacterial single copy genes) trees, Gulbenkiania mobilis and Gulbenkiania indica clustered together. Based on the above results, we propose to reclassify Gulbenkiania indica Jyoti et al. 2010 as a later heterotypic synonym of Gulbenkiania mobilis Vaz-Moreira et al. 2007.