Genome sequencing-assisted identification and the first functional validation of N-acyl-homoserine-lactone synthases from the Sphingomonadaceae family.

BACKGROUND: Members of the genus Novosphingobium have been isolated from a variety of environmental niches. Although genomics analyses have suggested the presence of genes associated with quorum sensing signal production e.g., the N-acyl-homoserine lactone (AHL) synthase (luxI) homologs in various Novosphingobium species, to date, no luxI homologs have been experimentally validated. METHODS: In this study, we report the draft genome of the N-(AHL)-producing bacterium Novosphingobium subterraneum DSM 12447 and validate the functions of predicted luxI homologs from the bacterium through inducible heterologous expression in Agrobacterium tumefaciens strain NTL4. We developed a two-dimensional thin layer chromatography bioassay and used LC-ESI MS/MS analyses to separate, detect and identify the AHL signals produced by the N. subterraneum DSM 12447 strain. RESULTS: Three predicted luxI homologs were annotated to the locus tags NJ75_2841 (NovINsub1), NJ75_2498 (NovINsub2), and NJ75_4146 (NovINsub3). Inducible heterologous expression of each luxI homologs followed by LC-ESI MS/MS and two-dimensional reverse phase thin layer chromatography bioassays followed by bioluminescent ccd camera imaging indicate that the three LuxI homologs are able to produce a variety of medium-length AHL compounds. New insights into the LuxI phylogeny was also gleemed as inferred by Bayesian inference. DISCUSSION: This study significantly adds to our current understanding of quorum sensing in the genus Novosphingobium and provide the framework for future characterization of the phylogenetically interesting LuxI homologs from members of the genus Novosphingobium and more generally the family Sphingomonadaceae.

Whole-Genome Sequence and Classification of 11 Endophytic Bacteria from Poison Ivy (Toxicodendron radicans).

Here, we report the whole-genome sequences and annotation of 11 endophytic bacteria from poison ivy (Toxicodendron radicans) vine tissue. Five bacteria belong to the genus Pseudomonas, and six single members from other genera were found present in interior vine tissue of poison ivy.

Whole-Genome Sequencing and Annotation of Bacillus safensis RIT372 and Pseudomonas oryzihabitans RIT370 from Capsicum annuum (Bird's Eye Chili) and Capsicum chinense (Yellow Lantern Chili), Respectively.

Here, we report the genome sequences of Bacillus safensis RIT372 and Pseudomonas oryzihabitans RIT370 from Capsicum spp. Annotation revealed gene clusters for the synthesis of bacilysin, lichensin, and bacillibactin and sporulation killing factor (skfA) in Bacillus safensis RIT372 and turnerbactin and carotenoid in Pseudomonas oryzihabitans RIT370.