Kaistella flava sp. nov., isolated from Antarctic tundra soil, and emended descriptions of Kaistella yonginensis, Kaistella jeonii, Kaistella antarctica and Kaistella chaponensis.

A rod-shaped, yellow-pigmented, Gram-stain-negative, non-motile and aerobic bacterium, designated 7-3AT, was isolated from soil from King George Island, maritime Antarctica, and subjected to a polyphasic taxonomic study. Growth occurred at 4-37 °C (optimum, 20°C) and at pH 5.0-9.0 (optimum, pH 7.0-8.0). Tolerance to NaCl was up to 4 % (w/v) with optimum growth in the absence of NaCl. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 7-3AT represented a member of the family Flavobacteriaceae. Strain 7-3AT showed the highest sequence similarities with Kaistella yonginensis HMD 1043T (96.65 %), Kaistella carnis NCTC 13525T (96.53 %), Kaistella chaponensis DSM 23145T (96.27 %), Kaistella antarctica LMG 24720T (96.13 %) and Kaistella jeonii DSM 17048T (96.06 %). A whole genome-level comparison of 7-3AT with K. jeonii DSM 17048T, K. antarctica LMG 24720T, K. chaponensis DSM 23145T, and Kaistella palustris DSM 21579T revealed average nucleotide identity (ANI) values of 79.03, 82.25, 78.12, and 74.42 %, respectively. The major respiratory isoprenoid quinone was identified as MK-6 and a few ubiquinones Q-10 were identified. In addition, flexirubin-type pigments were absent. The polar lipid profile of 7-3AT was found to contain one phosphatidylethanolamine, six unidentified aminolipids (AL) and two unidentified lipids (L). The G+C content of the genomic DNA was determined to be 34.54 mol%. The main fatty acids were iso-C15 : 0, summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 0 10-methyl), anteiso-C15 : 0, iso-C13 : 0 and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). On the basis of the evidence presented in this study, a novel species of the genus Kaistella, Kaistella flava sp. nov., is proposed, with the type strain 7-3AT (=CCTCC AB 2016141T= KCTC 52492T). Emended descriptions of Kaistella yonginensis, Kaistella jeonii, Kaistella antarctica and Kaistella chaponensis are also given.