Lysobacter fragariae sp. nov. and Lysobacter rhizosphaerae sp. nov. isolated from rhizosphere of strawberry plant.

Abstract

Two bacterial strains, designated THG-DN8.7(T) and THG-DN8.3(T), were isolated from the rhizosphere of a strawberry plant in Gyeryong Mountain, South Korea. Cells of both isolates were observed to be Gram-negative, yellow-coloured and rod-shaped. Comparative 16S rRNA gene sequence analysis showed that strain THG-DN8.7(T) had highest sequence similarities to Lysobacter yangpyeongensis KACC 11407(T) (97.2%), Lysobacter niabensis KACC 11587(T) (97.0%) and Lysobacter oryzae KCTC 22249(T) (96.9%), while strain THG-DN8.3(T) had closely similarity with L. niabensis KACC 11587(T) (98.1%), L. oryzae KCTC 22249(T) (97.1%) and L. yangpyeongensis KACC 11407(T) (96.1%). DNA-DNA relatedness values between strains THG-DN8.7(T) and THG-DN8.3(T) and their closest phylogenetically neighbours were below 30.0%, which indicates that strains THG-DN8.7(T) and THG-DN8.3(T) represent distinct species within the genus Lysobacter. Both strains were found to contain iso-C15:0, iso-C16:0 and iso-C17:1 ω9c as predominant fatty acids and ubiquinone-8 as major isoprenoid quinone. The major polar lipids were identified as phosphatidylethanolamine, phosphatidyl-N-methylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content of strains THG-DN8.7(T) and THG-DN8.3(T) were determined to be 66.9 and 67.8mol%, respectively. These data are consistent with the affiliation of the two new species represented by THG-DN8.7(T) and THG-DN8.3(T) to the genus Lysobacter. The names Lysobacter fragariae sp. nov. and Lysobacter rhizosphaerae sp. nov. are proposed for these species with the type strains THG-DN8.7(T) (=KCTC 42236(T)=JCM 30322(T)) and THG-DN8.3(T) (=KCTC 42237(T)=JCM 30321(T)), respectively.