Halomonas rhizosphaerae sp. nov. and Halomonas kalidii sp. nov., two novel moderate halophilic phenolic acid-degrading species isolated from saline soil

Abstract

Four vanillic acid-degrading bacterial strains, named LR5S13^T, LR5S20, and M4R5S39^T and LN1S58, were isolated from Kalidium cuspidatum rhizosphere and bulk soils, respectively. Phylogenetic analysis based on 16S rRNA gene as well as core genome revealed that LR5S13^T and LR5S20 clustered closely with each other and with Halomonas ventosae Al12^T, and that the two strains shared the highest similarities (both 99.3 %) with H. ventosae Al12^T, in contrast, M4R5S39^T and LN1S58 clustered together and with Halomonas heilongjiangensis 9–2^T, and the two strains shared the highest similarities (99.4 and 99.2 %, respectively) with H. heilongjiangensis 9–2^T. The average nucleotides identities based on BLAST (ANIb) and digital DNA-DNA hybridization (dDDH) values of strains LR5S13^T to LR5S20, and M4R5S39^T to LN1S58, were both higher than the threshold values for delineation of a species. The ANIb and dDDH values of the four strains to their closely relatives were lower than the threshold values. All four strains take phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol as the major polar lipids, Summed Feature 8, Summed Feature 3, and C_16:0 as the major fatty acids. Based on the phylogenetic and phenotypic results, the four strains should be classified as two novel Halomonas species. Therefore, Halomonas rhizosphaerae sp. nov. (type strain LR5S13^T = KCTC 8016^T = CGMCC 1.62049^T) and Halomonas kalidii (type strain M4R5S39^T = KCTC 8015^T = CGMCC 1.62047^T) are proposed. The geographical distribution analysis based on 16S rRNA gene revealed that the two novel species are widely distributed across the globe, specifically in highly saline habits, especially in Central and Eastern Asia.