Lysobacter stagni sp. nov. and Limnohabitans lacus sp. nov., isolated from a pond.

Two Gram-negative bacteria, designated as strains LF1T and HM2-2T, were isolated from an artificial pond in a honey farm at Hoengseong-gun, Gangwon-do, Republic of Korea. The 16S rRNA sequence analysis results revealed that strain LF1T belonged to the genus Lysobacter and had the highest sequence similarity to Lysobacter niastensis GH41-7T (99.0 %), Lysobacter panacisoli CJ29T (98.9 %), and Lysobacter prati SYSU H10001T (98.2 %). Its growth occurred at 20-37 °C, at pH 5.0-12.0, and in the presence of 0-2% NaCl. The major fatty acids were iso-C15 : 0, iso-C16 : 0, and summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The DNA G+C content was 67.5 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain LF1T and species of the genus Lysobacter were 79.1-84.4% and 22.0-27.5 %, respectively. The 16S rRNA sequence analysis results revealed that strain HM2-2T belonged to the genus Limnohabitans and was most closely related to Limnohabitans planktonicus II-D5T (98.9 %), Limnohabitans radicicola JUR4T (98.4%), and Limnohabitans parvus II-B4T (98.4 %). Its growth occurred at 10-35 °C, at pH 5.0-11.0, and in the presence of 0-2% NaCl. The major fatty acids were C16 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The major polar lipid was phosphatidylethanolamine. The DNA G+C content was 59.9 mol%. The ANI and dDDH values between strain HM2-2T and its closely related strains were 75.1-83.0% and 20.4-26.4 %, respectively. Phenotypic, genomic, and phylogenetic data revealed that strains LF1T and HM2-2T represent novel species in the genera Lysobacter and Limnohabitans, for which the names Lysobacter stagni sp. nov. and Limnohabitans lacus sp. nov. are proposed, respectively. The type strain of Lys. stagni is LF1T (=KACC 23251T=TBRC 17648T), and that of Lim. lacus is HM2-2T (=KACC 23250T=TBRC 17649T).

Critical analysis of polycyclic tetramate macrolactam biosynthetic gene cluster phylogeny and functional diversity.

Polycyclic tetramate macrolactams (PTMs) are bioactive natural products commonly associated with certain actinobacterial and proteobacterial lineages. These molecules have been the subject of numerous structure-activity investigations since the 1970s. New members continue to be pursued in wild and engineered bacterial strains, and advances in PTM biosynthesis suggest their outwardly simplistic biosynthetic gene clusters (BGCs) belie unexpected product complexity. To address the origins of this complexity and understand its influence on PTM discovery, we engaged in a combination of bioinformatics to systematically classify PTM BGCs and PTM-targeted metabolomics to compare the products of select BGC types. By comparing groups of producers and BGC mutants, we exposed knowledge gaps that complicate bioinformatics-driven product predictions. In sum, we provide new insights into the evolution of PTM BGCs while systematically accounting for the PTMs discovered thus far. The combined computational and metabologenomic findings presented here should prove useful for guiding future discovery.IMPORTANCEPolycyclic tetramate macrolactam (PTM) pathways are frequently found within the genomes of biotechnologically important bacteria, including Streptomyces and Lysobacter spp. Their molecular products are typically bioactive, having substantial agricultural and therapeutic interest. Leveraging bacterial genomics for the discovery of new related molecules is thus desirable, but drawing accurate structural predictions from bioinformatics alone remains challenging. This difficulty stems from a combination of previously underappreciated biosynthetic complexity and remaining knowledge gaps, compounded by a stream of yet-uncharacterized PTM biosynthetic loci gleaned from recently sequenced bacterial genomes. We engaged in the following study to create a useful framework for cataloging historic PTM clusters, identifying new cluster variations, and tracing evolutionary paths for these molecules. Our data suggest new PTM chemistry remains discoverable in nature. However, our metabolomic and mutational analyses emphasize the practical limitations of genomics-based discovery by exposing hidden complexity.

Lysobacter antarcticus sp. nov., an SUF-system-containing bacterium from Antarctic coastal sediment.

A Gram-stain-negative, heterotrophic, aerobic, non-motile, rod-shaped bacterial strain (GW1-59T) belonging to the genus Lysobacter was isolated from coastal sediment collected from the Chinese Great Wall Station, Antarctica. The strain was identified using a polyphasic taxonomic approach. The strain grew well on Reasoner's 2A media and could grow in the presence of 0-4 % (w/v) NaCl (optimum, 1 %), at pH 9.0-11.0 and at 15-37 °C (optimum, 30 °C). Strain GW1-59T possessed ubiquinone-8 as the sole respiratory quinone. The major phospholipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids were summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1 ω9c), iso-C15 : 0, iso-C16 : 0, iso-C17 : 0, C16 : 0 and iso-C11 : 0 3-OH. DNA-DNA relatedness with Lysobacter concretionis Ko07T, the nearest phylogenetic relative (98.5 % 16S rRNA gene sequence similarity) was 23.4 % (21.1-25.9 %). The average nucleotide identity value between strain GW1-59T and L. concretionis Ko07T was 80.1 %. The physiological and biochemical results and low level of DNA-DNA relatedness suggested the phenotypic and genotypic differentiation of strain GW1-59T from other Lysobacter species. On the basis of phenotypic, phylogenetic and genotypic data, a novel species, Lysobacter antarcticus sp. nov., is proposed. The type strain is GW1-59T (=CCTCC AB 2019390T=KCTC 72831T).

Lysobacter terrestris sp. nov., isolated from soil.

A yellow-pigmented, non-motile, Gram-stain-negative, rod-shaped bacterium, designated II4T was obtained from soil sampled at Seongnam, Gyeonggi-do, Republic of Korea. Cells were strictly aerobic, grew optimally at 20-28 °C and hydrolysed casein. A phylogenetic analysis based on its 16S rRNA gene sequence revealed that strain II4T formed a lineage within the family Xanthomonadaceae and clustered as members of the genus Lysobacter. The closest members were Lysobacter terrae THG-A13T (97.88 % sequence similarity), Lysobacter niabensis GH34-4T (97.82 %), Lysobacter oryzae YC6269T (97.74%), Lysobacter yangpyeongensis GH19-3T (97.53 %) and Lysobacter enzymogenes ATCC 29487T (96.18 %). The principal respiratory quinone was Q-8 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The predominant cellular fatty acids were summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1 ω9c) and iso-C15 : 0 and iso-C16 : 0. The DNA G+C content was 68.2 mol%. The average nucleotide identity and in silico DNA-DNA hybridization relatedness values between strain II4T and its closely related genus members with possible full genome sequences were ≤79.6 and 23.7 %, respectively. Based on genomic, chemotaxonomic, phenotypic and phylogenetic data, strain II4T represents novel species in the genus Lysobacter, for which the name Lyobacter terrestris sp. nov. is proposed. The type strain is II4T (=KACC 21196T=NBRC 113956T).

Lysobacter arenosi sp. nov. and Lysobacter solisilvae sp. nov. isolated from soil.

Two Gram-stain negative, yellow-pigmented, and mesophilic bacteria, designated strains R7T and R19T, were isolated from sandy and forest soil, South Korea, respectively. Both strains were non-motile rods showing catalase- and oxidase-positive activities. Both strains were shown to grow at 10-37°C and pH 6.0-9.0, and in the presence of 0-1.5% (w/v) NaCl. Strain R7T contained iso-C14:0, iso-C15:0, iso-C16:0, and summed feature 9 (comprising C16:0 10-methyl and/or iso-C17:1ω9c), whereas strain R19T contained iso-C11:0 3-OH, C16:1ω7c alcohol, iso-C11:0, iso-C15:0, iso-C16:0, and summed feature 9 (comprising C16:0 10-methyl and/or iso-C17:1ω9c) as major cellular fatty acids (> 5%). Both strains contained ubiquin-one-8 as the sole isoprenoid quinone and phosphatidylglycerol, phosphatidylethanolamine, and an unidentified phospholipid as the major polar lipids. The DNA G + C contents of strains R7T and R19T calculated from their genomes were 66.9 mol% and 68.9 mol%, respectively. Strains R7T and R19T were most closely related to Lysobacter panacisoli C8-1T and Lysobacter niabensis GH34-4T with 98.7% and 97.8% 16S rRNA sequence similarities, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains R7T and R19T formed distinct phylogenetic lineages within the genus Lysobacter. Based on phenotypic, chemotaxonomic, and molecular features, strains R7T and R19T represent novel species of the genus Lysobacter, for which the names Lysobacter arenosi sp. nov. and Lysobacter solisilvae sp. nov. are proposed. The type strains of L. arenosi and L. solisilvae are R7T (= KACC 21663T = JCM 34257T) and R19T (= KACC 21767T = JCM 34258T), respectively.

A non-flagellated, predatory soil bacterium reprograms a chemosensory system to control antifungal antibiotic production via cyclic di-GMP signalling.

Lysobacter enzymogenes is a non-flagellated, soil proteobacterium that secretes a diffusible antibiotic known as heat-stable antifungal factor (HSAF) to kill nearby fungi for food. The genome of the model strain OH11 encodes a homologous Wsp system, which is generally deployed by flagellated bacteria to achieve flagella-dependent outputs via a c-di-GMP-FleQ complex, in which c-di-GMP is a ubiquitous dinucleotide second messenger and FleQ is a transcription factor (TF). Here, we show that the Wsp system in the non-flagellated OH11 participates in a unique c-di-GMP-dependent signalling pathway and forms a WspR-CdgL binary complex to alter HSAF production, in which WspR and CdgL act as a c-di-GMP diguanylate cyclase (DGC) and a non-TF binding protein respectively. We found that the phosphorylation of WspR activates its DGC activity and enhances c-di-GMP production while inhibiting HSAF biosynthesis. The phosphorylation of WspR also plays a key role in weakening WspR-CdgL binding and HSAF generation. Interestingly, c-di-GMP binding to CdgL did not seem to induce the disassociation of the WspR-CdgL complex. These observations, along with our earlier findings, lead us to propose a model in which L. enzymogenes re-programs the Wsp system via c-di-GMP signalling to regulate HSAF biosynthesis for the benefit of ecological adaptation.

Lysobacter gilvus sp. nov., isolated from activated sludge.

Strain HX-5-24T was isolated from the sludge collected from the outlet of the biochemical treatment facility of an agricultural chemical plant in Maanshan city, Anhui province, PR China (118° 28' N, 31° 47' E). Cells were observed to be Gram-reaction-negative, rod-shaped, non-motile and aerobic. Strain HX-5-24T shared 99.1% 16S rRNA gene sequence similarity with Lysobacter dokdonensis DS-58T and less than 97% similarities with other type strains. The phylogenetic analysis based on 16S rRNA indicated that strain HX-5-24T belonged to the genus Lysobacter and formed a subclade with L. dokdonensis DS-58T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain HX-5-24T and L. dokdonensis DS-58T were 87.5% and 35.3%, respectively. The genomic DNA G + C content of the strain was 66.4%. The major fatty acids (> 5%) were iso-C15:0, anteiso-C15:0, iso-C16:0, C16:0 and summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl). The predominant quinone was ubiquinone Q-8. The polar lipid profile consisted of diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and phospholipids (PL). On the basis of phenotypic and phylogenetic evidences, strain HX-5-24T is considered as a novel species in the genus Lysobacter, for which the name Lysobacter gilvus sp. nov. is proposed. The type strain is HX-5-24T (= KCTC 72470T = CCTCC AB 2019228T).

Lysobacter telluris sp. nov., isolated from Korean rhizosphere soil.

A Gram-stain-negative, aerobic, non-motile, non-spore-forming light-yellow-coloured rod-shaped bacterial strain, designated YJ15T, was isolated from soil at Bigeum island in Korea. Growth was observed at 10-37 °C (optimum, 28 °C), at pH 6.0-7.5 (optimum, pH 7.0) and in the absence of NaCl. Based on 16S rRNA gene sequence analysis, strain YJ15T was closely related to 'Lysobacter tongrenensis' YS037T (97.8%), Lysobacter pocheonensis Gsoil193T (96.5%) and Lysobacter daecheongensis Dae08T (95.8%) and phylogenetically grouped together with 'Lysobacter tongrenensis' YS037T, Lysobacter dokdonensis DS-58T and Lysobacter pocheonensis Gsoil 193T. The DNA-DNA relatedness between strain YJ15T and 'Lysobacter tongrenensis' KCTC 52206T was 12% and the phylogenomic analysis based on the whole genome sequence demonstrated that strain YJ20T formed a distinct phyletic line with Lysobacterlter dokdonensis DS-58T showing average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values of 76.3 and 21.3%, respectively. The predominant ubiquinone was identified as Q-8, and polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and two unidentified aminolipids. The major fatty acids were iso-C17:1 ω9c, iso-C15:0, iso-C16:0 and iso-C17:0. The genomic DNA G + C content was 68.2 mol %. On the basis of phenotypic, chemotaxonomic properties and phylogenetic analyses in this study, strain YJ15T is considered to represent a novel species of the genus Lysobacter, for which the name Lysobacter telluris sp. nov. is proposed. The type strain is YJ15T (= KACC 19552T = NBRC 113197T).

Characterization of Lysobacter spp. strains and their potential use as biocontrol agents against pear anthracnose.

Colletotrichum fructicola, is an important fungal pathogen that has been reported to cause pear (Pyrus) anthracnose in China, resulting in substantial economic losses due to severe defoliation and decreased fruit quality and yield. In the search for novel strategies to control pear anthracnose, Lysobacter strains have drawn a great deal of attention due to their high-level production of extracellular enzymes and bioactive metabolites. In the present study, we compared four Lysobacter strains including Lysobacter enzymogenes OH11, Lysobacter antibioticus OH13, Lysobacter gummosus OH17 and Lysobacter brunescens OH23 with respect to their characteristics and activity against pear anthracnose caused by C. fructicola. The results showed that the evaluated Lysobacter species presented various colony morphologies when cultured on different media and were proficient in producing protease, chitinase, cellulase and glucanase, with L. enzymogenes OH11 showing typical twitching motility. L. enzymogenes OH11 and L. gummosus OH17 showed potent activity against the tested fungi and oomycetes. L. gummosus OH17 produced HSAF (heat-stable antifungal factor) which was demonstrated to be a major antifungal factor in L. enzymogenes OH11 and C3. Furthermore, L. antibioticus OH13 and L. brunescens OH23 exhibited strong antibacterial activity, especially against Xanthomonas species. Cultures of L. enzymogenes OH11 protected pear against anthracnose caused by C. fructicola, and the in vivo results indicated that treatment with an L. enzymogenes OH11 culture could decrease the diameter of lesions in pears by 35 % and reduce the severity of rot symptoms compared to that observed in the control. In the present study, we systemically compared four Lysobacter strains and demonstrated that they have strong antagonistic activity against a range of pathogens, demonstrating their promise in the development of biological control agents.

Lysobacter profundi sp. nov., isolated from freshwater sediment and reclassification of Lysobacter panaciterrae as Luteimonas panaciterrae comb. nov.

A polyphasic taxonomic study was carried out on strains CHu50b-3-2T and CHu40b-3-1 isolated from a 67 cm-long sediment core collected from the Daechung Reservoir at a water depth of 17 m, Daejeon, Republic of Korea. The cells of the strains were Gram-stain-negative, non-spore-forming, non-motile and rod-shaped. Comparative 16S rRNA gene sequence studies showed a clear affiliation of two strains with γ-Proteobacteria, which showed the highest pairwise sequence similarities to Lysobacter hankyongensis KTce-2T (96.5 %), Lysobacter pocheonensis Gsoil193T (96.3 %), Lysobacter ginsengisoli Gsoil 357T (96.1 %), Lysobacter solanacearum T20R-70T (96.1 %), Lysobacter brunescens KCTC 12130T (95.4 %) and Lysobacter capsici YC5194T (95.3 %). The phylogenetic analysis based on 16S rRNA gene sequences showed that the strains formed a clear phylogenetic lineage with the genus Lysobacter. The major fatty acids were identified as summed feature 9 (iso-C17 : 1 ω9c and/or C18 : 1 10-methyl), iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. The respiratory quinone was identified as ubiquinone Q-8. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The genomic DNA G+C content was determined to be 66.8 mol% (genome) for strain CHu50b-3-2T and 66.4 mol% (HPLC) for strain CHu40b-3-1. Based on the combined genotypic and phenotypic data, we propose that strains CHu50b-3-2T and CHu40b-3-1 represent a novel species of the genus Lysobacter, for which the name Lysobacter profundi sp. nov. is proposed. The type strain is CHu50b-3-2T (=KCTC 72973T=CCTCC AB 2019129T). Besides Lysobacter panaciterrae Gsoil 068T formed a phylogenetic group together with strain Luteimonas aquatica RIB1-20T (EF626688) that is clearly separated from all other known Lysobacter strains. Based on the phylogenetic relationships together with fatty acid compositions, Lysobacter panaciterrae Gsoil 068T should be reclassified as a member of the genus Luteimonas: Luteimonas aquatica comb. nov. (type strain Gsoil 068T=KCTC 12601T=DSM 17927T).

Lysobacter lacus sp. nov., isolated from from lake sediment.

An aerobic and Gram-stain-negative bacterial strain, designated UKS-15T, was isolated from lake water in the Republic of Korea. Results of 16S rRNA gene sequence and phylogenetic analyses indicated that the novel isolate belongs to the genus Lysobacter and was most closely related to Lysobacter xinjiangensis RCML-52T (98.0 %), Lysobacter mobilis 9 NM-14T (97.4 %) and Lysobacter humi FJY8T (97.2 %). The DNA G+C content was 69.1 mol%. Strain UKS-15T possessed ubiquinone-8 (Q-8) as the sole respiratory quinone and the fatty acid profile comprised iso-C15 : 0, iso-C17 : 0 and summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl) as its major components. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one unidentified aminophospholipid. Moreover, the physiological and biochemical results and low level of DNA-DNA relatedness (<22.0 %) allowed the phenotypic and genotypic differentiation of strain UKS-15T from other Lysobacter species. Therefore, on the basis of the data from this polyphasic taxonomic study, strain UKS-15T should represent a novel species of the genus Lysobacter, for which the name Lysobacter lacus sp. nov. is proposed. The type strain is UKS-15T (=JCM 30983T=KACC 18719T).

Transition of the Bacterial Community and Culturable Chitinolytic Bacteria in Chitin-treated Upland Soil: From Streptomyces to Methionine-auxotrophic Lysobacter and Other Genera.

Chitin amendment is an agricultural management strategy for controlling soil-borne plant disease. We previously reported an exponential decrease in chitin added to incubated upland soil. We herein investigated the transition of the bacterial community structure in chitin-degrading soil samples over time and the characteristics of chitinolytic bacteria in order to elucidate changes in the chitinolytic bacterial community structure during chitin degradation. The addition of chitin to soil immediately increased the population of bacteria in the genus Streptomyces, which is the main decomposer of chitin in soil environments. Lysobacter, Pseudoxanthomonas, Cellulosimicrobium, Streptosporangium, and Nonomuraea populations increased over time with decreases in that of Streptomyces. We isolated 104 strains of chitinolytic bacteria, among which six strains were classified as Lysobacter, from chitin-treated soils. These results suggested the involvement of Lysobacter as well as Streptomyces as chitin decomposers in the degradation of chitin added to soil. Lysobacter isolates required yeast extract or casamino acid for significant growth on minimal agar medium supplemented with glucose. Further nutritional analyses demonstrated that the six chitinolytic Lysobacter isolates required methionine (Met) to grow, but not cysteine or homocysteine, indicating Met auxotrophy. Met auxotrophy was also observed in two of the five type strains of Lysobacter spp. tested, and these Met auxotrophs used d-Met as well as l-Met. The addition of Met to incubated upland soil increased the population of Lysobacter. Met may be a factor increasing the population of Lysobacter in chitin-treated upland soil.

Lysobacter prati sp. nov., isolated from a plateau meadow sample.

A novel proteobacterial strain designated SYSU H10001T was isolated from a soil sample collected from plateau meadow in Hongyuan county, Sichuan province, south-western China. The taxonomic position of the strain was investigated using a polyphasic approach. On the basis of 16S rRNA gene sequence similarities and phylogenetic analysis, strain SYSU H10001T was most closely related to Lysobacter soli KCTC 22011T (98.6%, sequence similarity) and Lysobacter panacisoli JCM 19212T (98.2%). The prediction result of secondary metabolites based on genome shown that the strain SYSU H10001T contained 3 clusters of bacteriocins, 1 cluster of non-ribosomal peptide synthetase, 1 cluster of type 1 polyketide synthase and 1 cluster of arylpolyene. In addition, the major isoprenoid quinone was Q-8 and the major fatty acids were identified as iso-C15:0, iso-C17:0 and Summed feature 9. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and three unidentified phospholipids. The genomic DNA G + C content of strain SYSU H10001T was 66.5% (genome). On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU H10001T represents a novel species of the genus Lysobacter, for which the name Lysobacter prati sp. nov. is proposed. The type strain is SYSU H10001T (= KCTC 72062T = CGMCC 1.16662T).

Lysobacter terrigena sp. nov., isolated from a Korean soil sample.

A bacterial strain isolated from a soil collected in Jeju Island, designated as 17J7-1T, was Gram-negative, rod-shaped, yellow colored, and motile by gliding. This strain was able to grow at temperature range from 10 to 42 °C, pH 7-9, and tolerated up to 1% NaCl. Analysis of 16S rRNA sequence identified strain 17J7-1T as a member of the genus Lysobacter with close sequence similarity with Lysobacter mobilis 9NM-14T (97.4%), Lysobacter xinjiangensis RCML-52T (97.0%), and Lysobacter humi FJY8T (96.9%). The genomic DNA G + C content of the isolate was 67.9 mol%. DNA-DNA relatedness between strain 17J7-1T and L. mobilis, L. humi, and L. xinjiangensis were 42.3%, 39.5%, and 35.8%, respectively, clearly showing that the isolate is distinct from its closest phylogenetic neighbors in the genus Lysobacter. Average nucleotide identity (ANI) and digital DNA-DNAhybridization (dDDH) values between strain 17J7-1T and L. enzymogenes ATCC 29487T, the type species of this genus, and several other close Lysobacter species were less than 77% and 22%, respectively. Major fatty acids were C16:0 iso (29.8%), summed feature 9 (C17:1 iso ω9c/C16:0 10-methyl; 20.1%), and C15:0 iso (17.7%). The predominant respiratory quinone was ubiquinone Q-8 and the major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. In the light of the polyphasic evidence accumulated in this study, strain 17J7-1T is considered to represent a novel species in the genus Lysobacter, for which name Lysobacter terrigena sp. nov. is proposed. The type strain is 17J7-1T (= KCTC 62217T = JCM 33057T).

Lysobacter alkalisoli sp. nov., a chitin-degrading strain isolated from saline-alkaline soil.

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.

Lysobacter oculi sp. nov., isolated from human Meibomian gland secretions.

A Gram-stain negative, rod-shaped bacterial, catalase and oxidase positive strain (83-4T) that formed yellow colonies was isolated from human Meibomian gland secretions. Strain 83-4T belongs to the genus Lysobacter according to phylogenetic analysis based on 16S rRNA gene sequences. The DNA G+C content was 67.1 mol%. The circular genome was 2.6 Mb, which contained 2431 protein-coding sequences, 75 pseudogenes, 46 tRNAs, 3 rRNAs and 4 ncRNAs. A bacteriocin cluster and aryl polyene cluster were also found in the genome. The average nucleotide identity value was 79.6% between isolate 83-4T and the closely related type strain Lysobacter tolerans UM1T. The estimated DNA-DNA hybridization value between strain 83-4T and L. tolerans UM1T was 41.6%. Diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol were the major polar lipids. Iso-C15:0, iso-C11:0 3-OH, iso-C11:0 and summed feature 9 (iso-C17:1ω9c) were the major fatty acids. Ubiquinone (Q-8) was the only respiratory quinone. Therefore, based on the data of phylogenetic analysis, chemotaxonomical and biochemical analyses, it is concluded that strain 83-4T represents a novel species of the genus Lysobacter with the name of Lysobacter oculi sp. nov. The type strain is 83-4T (= CGMCC 1.13464T = NRBC 113451T).

Lysobacter segetis sp. nov., Isolated from Soil.

A Gram-negative, aerobic, motile by gliding, rod-shaped bacterium, strain 17J68-2T, was isolated from a soil sample taken from Jeju Island, Republic of Korea. The isolate displayed high 16S rRNA gene sequence similarity to the members of the genus Lysobacter in the family Lysobacteraceae, with Lysobacter humi FJY8T (98.4% similarity), Lysobacter xinjiangensis RCML-52T (98.3%), and Lysobacter mobilis 9NM-14T (98.1%) as closest phylogenetic neighbors. Growth of strain 17J68-2T occurred at 15-42 °C, pH 7-8, and in the presence of 0-1.0% NaCl. Draft genome was 2.94 Mb in size with G+C content of 70.5 mol%. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine. Ubiquinone Q-8 was the predominant respiratory quinone and the major fatty acids were C16:0 iso (39.4%), summed feature 3 (C16:1ω7c/C16:1ω6c) (6.6%), C11:0 iso 3-OH (6.4%), C15:0 iso (6.4%), and C16:1 iso H (6.2%). The DNA-DNA relatedness between strain 17J68-2T and L. humi, L. xinjiangensis, and L. mobilis were 39.9, 39.4, and 25.3%, respectively. From these results, it is concluded that the novel isolate possesses sufficient characteristics to differentiate it from the most closely affiliated Lysobacter species, and strain 17J68-2T represents a novel species of the genus Lysobacter, for which the name Lysobacter segetis sp. nov. (=KCTC 62237T = JCM 33058T) is proposed.

Lysobacter caseinilyticus, sp. nov., a casein hydrolyzing bacterium isolated from sea water.

A novel bacterial strain, designated KVB24T, was isolated from sea-water of Busan Harbour in South Korea. Cells of strain KVB24T were Gram-stain negative, aerobic, rod shaped and non-motile. Strain KVB24T grew optimally at 25-28 °C and pH 6.5-7.0. Based on 16S rRNA gene sequence analysis, strain KVB24T was shown to belong to the genus Lysobacter within the class Gammaproteobacteria and to be closely related to Lysobacter dokdonensis DS-58T, Lysobacter hankyongensis KTce-2T and Lysobacter niastensis GH41-7T. DNA-DNA relatedness between strain KVB24T and its current closest relative was below 70%. The predominant fatty acids of strain KVB24T were iso-C11:0, iso-C11:0 3-OH, iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:0 and summed feature 9 comprising (iso-C17:1 ω9c and/or 10 methyl C16:0); the prominent isoprenoid was Q-8 and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The G + C content of genomic DNA from strain KVB24T was determined to be 67.5 mol%. Based on the phenotypic, genotypic and chemotaxonomic analyses, strain KVB24T represents a novel species of the genus Lysobacter, for which the name Lysobacter caseinilyticus sp. nov. is proposed. The type strain is KVB24T (= KACC19816T = JCM32879T).

Proposal of Lysobacter pythonis sp. nov. isolated from royal pythons (Python regius).

The bacterial strains 4284/11T and 812/17 isolated from the respiratory tract of two royal pythons in 2011 and 2017, respectively were subjected to taxonomic characterization. The 16S rRNA gene sequences of the two strains were identical and showed highest sequence similarities to Lysobacter tolerans UM1T (97.2%) and Luteimonas aestuarii DSM 19680T (96.7 %). The two strains were identical in the sequences of the 16S-23S rRNA internal transcribed spacer (ITS) and partial groEL gene sequences and almost identical in genomic fingerprints. In the ITS sequence Ly. tolerans DSM 28473T and in the groEL nucleotide sequence Luteimonas mephitis DSM 12574T showed the highest similarity. In silico DDH analyses using genome sequence based ANIb and gANI similarity coefficients demonstrated that strain 4284/11T represents a novel species and revealed Ly. tolerans UM1T as the next relative (ANIb = 76.2 %, gANI = 78.0 %). Based on the topology of a core gene phylogeny strain 4284/11T could be assigned to the genus Lysobacter. Chemotaxonomic characteristics including polyamine pattern, quinone system, polar lipid profile and fatty acid profile were in accordance with the characteristics of the genera Lysobacter and Luteimonas. Strains 4284/11T and 812/17 could be differentiated from the type strains of the most closely related species by several physiological tests. In conclusion we are here proposing the novel species Lysobacter pythonis sp. nov. The type strain is 4284/11T (= CCM 8829T = CCUG 72164T = LMG 30630T) and strain 812/17 (CCM 8830) is a second strain of this species.

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

Two bacterial strains, designated D10T and U8T, 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 D10T showed high 16S rRNA gene sequence similarities with Lysobacter humi FJY8T (99.0%), Lysobacter xinjiangensis RCML-52T (98.9%) and Lysobacter mobilis 9NM-14T (97.2%), whereas strain U8T showed high sequence similarities to L. mobilis 9NM-14T (97.9%), L. xinjiangensis RCML-52T (97.8%), L. humi FJY8T (97.5%) and Lysobacter bugurensis ZLD-29T (97.1%). The 16S rRNA gene sequence similarity between D10T and U8T was 97.0%. Strain D10T showed low DNA-DNA relatedness to U8T (57.7 ± 3.4%), L. humi FJY8T (48.8 ± 4.3%), L. xinjiangensis RCML-52T (60.1 ± 2.4%) and L. mobilis 9NM-14T (55.9 ± 1.9%). The level of DNA-DNA relatedness for strain U8T with respect to D10T, L. mobilis 9NM-14T, L. xinjiangensis RCML-52T, L. humi FJY8T, and L. bugurensis ZLD-29T 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-C15:0, iso-C16:0 and summed feature 9 (iso-C17:1 ω9c/C16:0 10-methyl), and ubiquinone (Q-8) as the only isoprenoid quinone for both strains. The DNA G + C contents of the strains D10T and U8T were determined to be 70.2 mol% and 70.6 mol%. On the basis of phenotypic, genotypic, chemotaxonomic, and phylogenetic analysis, both strains D10T and U8T 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 D10T (= KCTC 62111T = JCM 32364T) and the type strain of L. xanthus is U8T (= KCTC 62112T = JCM 32365T).