Abstract
We isolated a novel strain, R1DC25T, described as Kaustia mangrovi gen. nov. sp. nov. from the sediments of a mangrove forest on the coast of the Red Sea in Saudi Arabia. This isolate is a moderately halophilic, aerobic/facultatively anaerobic Gram- stainnegative bacterium showing optimum growth at between 30 and 40 degrees C, at a pH of 8.5 and with 3-5 % NaCl. The genome of R1DC25T comprises a circular chromosome that is 4 630 536 bp in length, with a DNA G+C content of 67.3 mol%. Phylogenetic analyses based on the 16S rRNA gene sequence and whole- genome multilocus sequence analysis of 120 concatenated singlecopy genes revealed that R1DC25T represents a distinct lineage within the family Parvibaculaceae in the order Rhizobiales within the class Alphaproteobacteria. R1DC25T showing 95.8, 95.3 and 94.5 % 16S rRNA gene sequence identity with Rhodoligotrophos appendicifer, Rhodoligotrophos jinshengii and Rhodoligotrophos defluvii, respectively. The predominant quinone was Q-10, and the polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, as well as several distinct aminolipids and lipids. The predominant cellular fatty acids were C19: 0 cyclo omega 8c, a combination of C18:1 omega 7c and/or C18:1 omega 6c and C16:0. On the basis of the differences in the phenotypic, physiological and biochemical characteristics from its known relatives and the results of our phylogenetic analyses, R1DC25T (=KCTC 72348T;=JCM 33619T;=NCCB 100699T) is proposed to represent a novel species in a novel genus, and we propose the name Kaustia mangrovi gen. nov., sp. nov. (Kaustia, subjective name derived from the abbreviation KAUST for King Abdullah University of Science and Technology; mangrovi, of a mangrove).