Exemplar Abstract for Lysobacter enzymogenes cookii Christensen and Cook 1978.

Two bacterial strains, designated GH34-4T and GH41-7T, were isolated from greenhouse soil cultivated with cucumber. The bacteria were strictly aerobic, Gram-negative, rod-shaped and oxidase- and catalase-positive. 16S rRNA gene sequence analysis indicated that these strains belong to the genus Lysobacter within the Gammaproteobacteria. Strain GH34-4T showed highest sequence similarity to Lysobacter yangpyeongensis GH19-3T (97.5 %) and Lysobacter koreensis Dae16T (96.4 %), and strain GH41-7T showed highest sequence similarity to Lysobacter antibioticus DSM 2044T (97.5 %), Lysobacter enzymogenes DSM 2043T (97.5 %) and Lysobacter gummosus ATCC 29489T (97.4 %). Levels of DNA–DNA relatedness indicated that strains GH34-4T and GH41-7T represented species clearly different from L. yangpyeongensis, L. antibioticus, L. enzymogenes and L. gummosus. The major cellular fatty acids of strains GH34-4T and GH41-7T were iso-C16 : 0, iso-C15 : 0 and iso-C17 : 1 ω9c, and the major isoprenoid quinone was Q-8. The DNA G+C contents of GH34-4T and GH41-7T were 62.5 and 66.6 mol%, respectively. On the basis of the polyphasic taxonomic data presented, it is evident that each of these strains represents a novel species of the genus Lysobacter, for which the names Lysobacter niabensis sp. nov. (type strain GH34-4T=KACC 11587T=DSM 18244T) and Lysobacter niastensis sp. nov. (type strain GH41-7T=KACC 11588T=DSM 18481T) are proposed.

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Insights into the distinct cooperation between the transcription factor Clp and Le DSF signaling in the regulation of antifungal factors in Lysobacter enzymogenes OH11

Biological Control ◽

10.1016/j.biocontrol.2016.08.006 ◽

2018 ◽

Vol 120 ◽

pp. 52-58 ◽

Cited By ~ 4

Author(s):

Gaoge Xu ◽

Xiaofeng Shi ◽

Ruping Wang ◽

Huiyong Xu ◽

Liangcheng Du ◽

...

Keyword(s):

Transcription Factor ◽

Lysobacter Enzymogenes

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Diguanylate cyclase and phosphodiesterase interact to maintain the specificity of c-di-GMP signaling in the regulation of antibiotic synthesis in Lysobacter enzymogenes

Applied and Environmental Microbiology ◽

10.1128/aem.01895-21 ◽

2021 ◽

Author(s):

Gaoge Xu ◽

Lichuan Zhou ◽

Guoliang Qian ◽

Fengquan Liu

Keyword(s):

Direct Evidence ◽

Antibiotic Production ◽

Indirect Evidence ◽

Second Messenger ◽

Antibiotic Biosynthesis ◽

Diguanylate Cyclase ◽

Signaling Specificity ◽

Lysobacter Enzymogenes ◽

Subsequent Investigation ◽

Diguanylate Cyclases

Cyclic dimeric GMP (c-di-GMP) is a universal second messenger in bacteria. The large number of c-di-GMP-related diguanylate cyclases (DGCs), phosphodiesterases (PDEs) and effectors are responsible for the complexity and dynamics of c-di-GMP signaling. Some of these components deploy various methods to avoid undesired crosstalk to maintain signaling specificity. Synthesis of the antibiotic HSAF ( H eat S table A ntifungal F actor) in Lysobacter enzymogenes is regulated by a specific c-di-GMP signaling pathway that includes a PDE LchP and a c-di-GMP effector Clp (also a transcriptional regulator). In the present study, from among 19 DGCs, we identified a diguanylate cyclase, LchD, which participates in this pathway. Subsequent investigation indicates that LchD and LchP physically interact and that the catalytic center of LchD is required for both the formation of the LchD-LchP complex and HSAF production. All the detected phenotypes support that LchD and LchP dispaly local c-di-GMP signaling to regulate HSAF biosynthesis. Although direct evidence is lacking, our investigation, which shows that the interaction between a DGC and a PDE maintains the specificity of c-di-GMP signaling, suggests the possibility of the existence of local c-di-GMP pools in bacteria. Importance Cyclic dimeric GMP (c-di-GMP) is a universal second messenger in bacteria. Signaling of c-di-GMP is complex and dynamic, and it is mediated by a large number of components, including c-di-GMP synthases (diguanylate cyclases. DGCs), c-di-GMP degrading enzymes (phosphodiesterases, PDEs), and c-di-GMP effectors. These components deploy various methods to avoid undesired crosstalk to maintain signaling specificity. In the present study, we identified a DGC that interacted with a PDE to specifically regulate antibiotic biosynthesis in L. enzymogenes . We provide direct evidence to show that the DGC and PDE form a complex, and also indirect evidence to argue that they may balance a local c-di-GMP pool to control the antibiotic production. The results represent an important finding regarding the mechanism of a pair of DGC and PDE to control the expression of specific c-di-GMP signaling pathways.

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The Homologous Components of Flagellar Type III Protein Apparatus Have Acquired a Novel Function to Control Twitching Motility in a Non-Flagellated Biocontrol Bacterium

Biomolecules ◽

10.3390/biom10050733 ◽

2020 ◽

Vol 10 (5) ◽

pp. 733 ◽

Cited By ~ 1

Author(s):

Alex M. Fulano ◽

Danyu Shen ◽

Miki Kinoshita ◽

Shan-Ho Chou ◽

Guoliang Qian

Keyword(s):

Pathogenic Bacteria ◽

Predatory Behavior ◽

Twitching Motility ◽

Bacterial Flagellum ◽

Lysobacter Enzymogenes ◽

Type Iii ◽

Type Iv ◽

Homologous Genes ◽

Flagellar Assembly

The bacterial flagellum is one of the best-studied surface-attached appendages in bacteria. Flagellar assembly in vivo is promoted by its own protein export apparatus, a type III secretion system (T3SS) in pathogenic bacteria. Lysobacter enzymogenes OH11 is a non-flagellated soil bacterium that utilizes type IV pilus (T4P)-driven twitching motility to prey upon nearby fungi for food. Interestingly, the strain OH11 encodes components homologous to the flagellar type III protein apparatus (FT3SS) on its genome, but it remains unknown whether this FT3SS-like system is functional. Here, we report that, despite the absence of flagella, the FT3SS homologous genes are responsible not only for the export of the heterologous flagellin in strain OH11 but also for twitching motility. Blocking the FT3SS-like system by in-frame deletion mutations in either flhB or fliI abolished the secretion of heterologous flagellin molecules into the culture medium, indicating that the FT3SS is functional in strain OH11. A deletion of flhA, flhB, fliI, or fliR inhibited T4P-driven twitching motility, whereas neither that of fliP nor fliQ did, suggesting that FlhA, FlhB, FliI, and FliR may obtain a novel function to modulate the twitching motility. The flagellar FliI ATPase was required for the secretion of the major pilus subunit, PilA, suggesting that FliI would have evolved to act as a PilB-like pilus ATPase. These observations lead to a plausible hypothesis that the non-flagellated L. enzymogenes OH11 could preserve FT3SS-like genes for acquiring a distinct function to regulate twitching motility associated with its predatory behavior.

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