Journal de phylogénétique et de biologie évolutive

Phylogenetic Analyses of the Genus Hymenobacter and Description of Siccationidurans gen. nov., and Parahymenobacter gen. nov

Abstract

Gundlapally Sathyanarayana Reddy

Phylogenetic analyses of 26 species of the genus Hymenobacter based on the 16S rRNA gene sequences, resulted in polyphyletic clustering with three major groups, arbitrarily named as Clade1, Clade2 and Clade3. Delineation of Clade1 and Clade3 from Clade2 was supported by robust clustering and high bootstrap values of more than 90% and 100% in all the phylogenetic methods. 16S rRNA gene sequence similarity shared by Clade1 and Clade2 was 88 to 93%, Clade1 and Clade3 was 88 to 91% and Clade2 and Clade3 was 89 to 92%. Based on robust phylogenetic clustering, less than 93.0% sequence similarity, unique in silico restriction patterns, presence of distinct signature nucleotides and signature motifs in their 16S rRNA gene sequences, two more genera were carved to accommodate species of Clade1 and Clade3. The name Hymenobacter, sensu stricto, was retained to represent 17 species of Clade2. For members of Clade1 and Clade3, the names Siccationidurans gen. nov. and Parahymenobacter gen. nov. were proposed, respectively, and species belonging to Clade1 and Clade3 were transferred to their respective genera. The genera Hymenobacter (sensu stricto), Siccationidurans gen. nov. and Parahymenobacter gen. nov. contained the signature motifs AAGGCTTTCTGAGTCGTAAA (414-432), TGACGGTACCTGAGGAATAA (480-499) and ATTAATACCGCATAACACT (168-185) in their 16S rRNA gene sequences, respectively. Further, the genus Hymenobacter was emended and proposed a more acceptable genus description.