Three novel Luteimonas species from a root and rhizosphere soil of Kalidium cuspidatum: Luteimonas endophytica sp. nov., Luteimonas rhizosphaericola sp. nov. and Luteimonas kalidii sp. nov

Three Gram-stain-negative, aerobic and rod-shaped bacterial strains, designated RD2P54T, M1R5S18T and M1R5S59T, were isolated from a root and rhizosphere soil of Kalidium cuspidatum, in Baotou, PR China. The three strains showed 94.1–98.7 % 16S rRNA gene sequence similarities to Luteimonas strains, indicating they belonged to the genus Luteimonas . The phylogenomic tree based on core genomes showed that strain RD2P54T tightly clustered with Luteimonas salinisoli SJ-92T, while strains M1R5S18T and M1R5S59T clustered with each other and with Luteimonas viscosa XBU10T and Luteimonas saliphila SJ-9T. Though strains M1R5S18T and M1R5S59T showed high 16S rRNA similarity (99.4 %) to each other, the low average nucleotide identity based on blast (ANIb; 88.6 %) and digital DNA–DNA hybridization (dDDH; 31.6 %) values between them indicated that they belonged to two different species. The ANIb and dDDH values of strains RD2P54T, M1R5S18T and M1R5S59T with their closely neighbours are well below the delineation threshold values for identifying strains as representing different species. All three strains take iso-C15 : 0 and summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1  ω9c) as major fatty acids, and ubiquinone-8 as the sole respiratory quinone. The major polar lipids of all three strains are diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Based on phenotypic and phylogenetic data, these three strains should be considered to represent three novel species of the genus Luteimonas , for which the names Luteimonas endophytica sp. nov. (type strain RD2P54T=CGMCC 1.61535T =KCTC 92470T), Luteimonas rhizosphaericola sp. nov. (type strain M1R5S18T=CGMCC 1.61537T =KCTC 92469T) and Luteimonas kalidii sp. nov. (type strain M1R5S59T=CGMCC 1.61536T =KCTC 92471T) are proposed.

Ruania suaedae sp. nov. and Ruania halotolerans sp. nov., two actinobacteria isolated from saline soil, and reclassification of Haloactinobacterium kanbiaonis as Occultella kanbiaonis comb. nov

Two Gram-stain-positive, non-motile, strictly aerobic, yellow-coloured, rod-shaped bacterial strains, designated LR1S40T and M4N3S171T, were isolated from rhizosphere and bulk saline soil of Suaeda salsa collected in Inner Mongolia, China. Phylogenetic trees based on 16S rRNA gene and whole genome sequences showed that the two strains clustered tightly with strains of the genus Ruania . Strains LR1S40T and M4N3S171T had 95.5% 16S rRNA gene similarity to each other, and strain LR1S40T had 98.8, 98.7, 97.4 and <97.0% similarity to Ruania alkalisoli RN3S43T, Ruania rhizosphaerae LNNU 22110T, Ruania alba YIM 93306T and all other current type strains, while strain M4N3S171T had 98.6 and <97.0% similarity to R. alba YIM 93306T, and all other current type strains, respectively. The average nucleotide identity based on blast (ANIb) and digital DNA–DNA hybridization (dDDH) values of LR1S40T and M4N3S171T with each other and to the other type strains of Ruania were well below the threshold values (95% for ANIb, 70% for dDDH) for differentiating a species. Diphosphatidylglycerol and phosphatidylglycerol were the major polar lipids in both strains. The predominant menaquinone in both strains was both MK-8. The genome of strain LR1S40T consisted of a 3557440 bp circular chromosome, with a G+C content of 71.1 mol%, while the genome of strain M4N3S171T consisted of 4270413 bp, with a G+C content of 67.6 mol%. The phylogenetic, physiological and phenotypic characteristics allowed discrimination of the two strains from their relatives. The names Ruania suaedae sp. nov. [type strain LR1S40T (=CGMCC 1.19028T=KCTC 49726T)] and Ruania halotolerans sp. nov. [type strain M4N3S171T (=CGMCC 1. 19142T=KCTC 49727T)] are therefore proposed. During the publication of Haloactinobacterium kanbiaonis , Haloactinobacterium glacieicola (type strain T3246-1T), which was selected as the reference strain for the identification of H. kanbiaonis , was reclassified as Occultella glacieicola . The two phylogenetic trees showed that H. kanbiaonis HY164T tightly clustered with Occultella aeris F300T, and had the highest 16S rRNA gene similarity (99.8%) to O. aeris F300T. Based on the phylogenetic analysis and the publication record, Haloactinobacterium kanbiaonis should be reclassified as Occultella kanbiaonis comb. nov.