Sandaracinobacteroides saxicola sp. nov., a Zeaxanthin-Producing and Halo-Sensitive Bacterium Isolated from Fully Weathered Granitic Soil, and the Diversity of Its ARHDs

Abstract

A yellow, Gram-stain-negative, aerobic, non-spore-forming, motile, and rod-shaped bacterial strain designated M6T was isolated from fully weathered granitic soil. The strain showing the highest 16S rRNA gene sequence similarity to M6T was Sandaracinobacteroides hominis SZY PN-1T (96.3%), the only species in the genus Sandaracinobacteroides. The average nucleotide identity and digital DNA-DNA hybridization value between these two strains were 72.6% and 18.0% respectively. Growth was inhibited by NaCl (≥0.1% (w/v)). Strain M6T contained C18:1ω7c (33.8%), C14:0 2-OH (16.6%), summed feature 3 (15.8%), and C16:0 (12.6%) as the major fatty acids. The polar lipids profile consisted of phosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid, four unidentified phospholipids, and four unidentified lipids. The genome of strain M6T was 3.4 Mb with 67.7% GC content. Further genomic analysis revealed a biosynthetic gene cluster for zeaxanthin, the production of which was verified by a high-resolution mass spectrum. The existence of multiple genes for aromatic ring-hydroxylating dioxygenases implies the potential ability for organic pollution controlling. The morphological, physiological, chemotaxonomic, and phylogenetic analysis clearly distinguished this strain from its phylogenetic neighbors, thus strain M6T represents a novel species of the genus Sandaracinobacteroides, for which the name Sandaracinobacteroides saxicola sp. nov. is proposed. The type of strain is M6T (=CGMCC 1.19164T=NBRC 115420T).