Lysobacter helvus sp. nov. and Lysobacter xanthus sp. nov., isolated from Soil in South Korea.

Two bacterial strains, designated D10^T and U8^T, were isolated from soil samples from the Dong-angyeong cave and Geommeolle wharf sea-coast, Udo-Island, Jeju, South Korea. Both novel bacterial strains are yellow-pigmented, Gram-stain negative, motile by means of monotrichous flagella, short rod shaped and strictly aerobic. A phylogenetic tree was reconstructed based on their 16S rRNA gene sequences, which indicated that these two strains belong to the genus Lysobacter within the family Xanthomonadaceae. Strain D10^T showed high 16S rRNA gene sequence similarities with Lysobacter humi FJY8^T (99.0%), Lysobacter xinjiangensis RCML-52^T (98.9%) and Lysobacter mobilis 9NM-14^T (97.2%), whereas strain U8^T showed high sequence similarities to L. mobilis 9NM-14^T (97.9%), L. xinjiangensis RCML-52^T (97.8%), L. humi FJY8^T (97.5%) and Lysobacter bugurensis ZLD-29^T (97.1%). The 16S rRNA gene sequence similarity between D10^T and U8^T was 97.0%. Strain D10^T showed low DNA–DNA relatedness to U8^T (57.7 ± 3.4%), L. humi FJY8^T (48.8 ± 4.3%), L. xinjiangensis RCML-52^T (60.1 ± 2.4%) and L. mobilis 9NM-14^T (55.9 ± 1.9%). The level of DNA–DNA relatedness for strain U8^T with respect to D10^T, L. mobilis 9NM-14^T, L. xinjiangensis RCML-52^T, L. humi FJY8^T, and L. bugurensis ZLD-29^T was 55.5 ± 0.5%, 54.5 ± 2.1%, 58.1 ± 0.8%, and 51.9 ± 3.4%, respectively. The major polar lipids for both strains were identified as diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The major cellular fatty acids for both strains were identified as iso-C_15:0, iso-C_16:0 and summed feature 9 (iso-C_17:1 ω9c/C_16:0 10-methyl), and ubiquinone (Q-8) as the only isoprenoid quinone for both strains. The DNA G + C contents of the strains D10^T and U8^T were determined to be 70.2 mol% and 70.6 mol%. On the basis of phenotypic, genotypic, chemotaxonomic, and phylogenetic analysis, both strains D10^T and U8^T represent a novel species in the genus Lysobacter, for which the names Lysobacter helvus sp. nov. and Lysobacter xanthus sp. nov. are proposed, respectively. The type strain of L. helvus is D10^T (= KCTC 62111^T = JCM 32364^T) and the type strain of L. xanthus is U8^T (= KCTC 62112^T = JCM 32365^T). [ABSTRACT FROM AUTHOR]