Strains of Lysobacter, thought to play vital roles in the environment for their high enzyme production capacity, are ubiquitous in various ecosystems. During an analysis of bacterial diversity in saline soil, a Gram-stain-negative, aerobic, chitin-degrading bacterial strain, designated SJ-36T, was isolated from saline-alkaline soil sampled at Tumd Right Banner, Inner Mongolia, PR China. Strain SJ-36T grew at 4-40 °C (optimum, 30 °C), pH 5.0-10.0 (optimum, pH 7.0-8.0) and 0-6 % NaCl (optimum, 1.0 %). Oxidase and catalase activities were positive. A phylogenetic tree based on 16S rRNA gene sequences and the phylogenomic tree both showed that strain SJ-36T formed a tight clade with Lysobacter maris KMU-14T (sharing 97.6 % 16S rRNA gene similarity) and Lysobacter aestuarii S2-CT (97.8 %). The major polar lipids of strain SJ-36T were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, two unidentified lipids and one unidentified phospholipid. The major fatty acids were iso-C15 : 0 (37.5 %), summed feature 9 (14.0 %; iso-C17 : 1ω9c and/or C16 : 0 10-methyl) and iso-C11 : 0 (10.6 %). Q-8 was the predominant ubiquinone. Its genomic DNA G+C content was 66.6 mol%. The average nucleotide identity values of strain SJ-36T to L. maris KMU-14T, L. aestuarii S2-CT and other type strains were 81.5, 79.1 and <79.0 %, respectively. The results of physiological, phenotypic and phylogenetic characterizations allowed the discrimination of strain SJ-36T from its phylogenetic relatives. Lysobacter alkalisoli sp. nov. is therefore proposed with strain SJ-36T (=CGMCC 1.16756T=KCTC 43039T) as the type strain.
Keywords: Lysobacter alkalisoli sp. nov.; chitin; degradation; polyphasic analysis; saline soil.