Key et al. Standards in Genomic Sciences (2016) 11:44 DOI 10.1186/s40793-016-0165-7 SHORTGENOMEREPORT Open Access Genome sequence of the organohalide- respiring Dehalogenimonas alkenigignens type strain (IP3-3T) Trent A. Key1, Dray P. Richmond1, Kimberly S. Bowman1, Yong-Joon Cho2, Jongsik Chun2, Milton S. da Costa3, Fred A. Rainey4 and William M. Moe1* Abstract Dehalogenimonas alkenigignens IP3-3T is a strictly anaerobic, mesophilic, Gram negative staining bacterium that grows by organohalide respiration, coupling the oxidation of H2 to the reductive dehalogenation of polychlorinated alkanes. Growth has not been observed with any non-polyhalogenated alkane electron acceptors. Here we describe the features of strain IP3-3T together with genome sequence information and its annotation. The 1,849,792 bp high-quality-draft genome contains 1936 predicted protein coding genes, 47 tRNA genes, a single large subunit rRNA (23S-5S) locus, and a single, orphan, small unit rRNA (16S) locus. The genome contains 29 predicted reductive dehalogenase genes, a large majority of which lack cognate genes encoding membrane anchoring proteins. Keywords: Chloroflexi, Dehalococcoidia, Reductive dechlorination, 1,2-dichloroethane, 1,2-dichloropropane, 1,2,3-trichloropropane Introduction [1–4]. In this report, we present a summary classification Strain IP3-3T (=JCM 17062, =NRRL B-59545) is the and a set of features for D. alkenigignens IP3-3T together type strain of the species Dehalogenimonas alkenigignens with the description of the draft genomic sequence and [1]. Currently, two pure cultures of D. alkenigignens have annotation. been described, namely, D. alkenigignens strains IP3-3T and SBP-1 [1]. Both strains were isolated from chlorinated Organism information alkane- and alkene-contaminated groundwater collected Classification and features at a Superfund Site near Baton Rouge, Louisiana (USA) Dehalogenimonas alkenigignens is a member of the order [1]. Construction of 16S rRNA gene libraries indicated Dehalococcoidales, class Dehalococcoidia, of the phylum that bacteria closely related or identical to D. alkeni- Chloroflexi (Table 1). Based on 16S rRNA gene sequences, gignens were present at high relative abundance in the T the closest related type strains are Dehalogenimonas groundwater where strains IP3-3 and SBP-1 were first lykanthroporepellens BL-DC-9T [1, 5] and Dehalococcoides isolated [1]. mccartyi 195T [6], with sequence identities of 96.2 and Strains of D. alkenigignens possess the unique trait of 90.6 %, respectively [1]. growing via organohalide respiration, a process in which Figure 1 shows the phylogenetic neighborhood of D. halogenated organic compounds are utilized as terminal alkenigignens strain IP3-3T in a 16S rRNA gene based electron acceptors. In particular, they are able to reduc- phylogenetic dendrogram. The sequence of the lone tively dehalogenate a variety of polychlorinated alkanes 16S rRNA gene copy in the draft genome is identical to that are of environmental concern on account of their thepreviouslypublished16SrRNAgenesequence potential to cause adverse health effects and their wide- (JQ994266). spread occurrence as soil and groundwater pollutants The cells of D. alkenigignens IP3-3T are Gram negative staining, non-spore forming, irregular cocci to disk- * Correspondence: [email protected] – μ 1Louisiana State University, Baton Rouge, LA, USA shaped with a diameter of 0.4 1.1 m [1] (Fig. 2). The Full list of author information is available at the end of the article strain was isolated in liquid medium using a dilution-to- © 2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Key et al. Standards in Genomic Sciences (2016) 11:44 Page 2 of 11 Table 1 Classification and general features of Dehalogenimonas and is resistant to ampicillin and vancomycin at concen- alkenigignens strain IP3-3T according to the MIGS trations of 1.0 and 0.1 g/l, respectively [1]. recommendations [55] D. alkenigignens IP3-3T is a strictly anaerobic chemo- MIGS ID Property Term Evidence troph, coupling utilization of H as an electron donor a 2 code and polychlorinated aliphatic alkanes as electron accep- Classification Domain Bacteria TAS [56] tors for growth. The chlorinated compounds known to Phylum Chloroflexi TAS [57, 58] be reductively dehalogenated include 1,2-dichloroethane, Class Dehalococcoidia TAS [6] 1,2-dichloropropane, 1,1,2,2-tetrachloroethane, 1,1,2-tri- Order Dehalococcoidales TAS [6] chloroethane, and 1,2,3-trichloropropane [1]. In all of the reductive dechlorination reactions characterized to Family Not reported date, strain IP3-3T appears to exclusively utilize vicinally ha- Genus Dehalogenimonas TAS [5] logenated alkanes as electron acceptors via dihaloelimina- Species Dehalogenimonas TAS [1] tion reactions (i.e., simultaneous removal of two chlorine alkenigignens atoms from adjacent carbon atoms with concomitant for- T Type strain IP3-3 TAS [1] mation of a carbon-carbon double bond) [1]. Strain IP3-3T Gram stain Negative TAS [1] does not utilize carbon tetrachloride (tetrachloromethane), Cell shape Coccoid, irregular TAS [1] 1-chlorobenzene, chloroform, 1-chloropropane, 2- Motility Non-motile TAS [1] chloropropane, 1,2-dichlorobenzene, 1,1-dichloroethane, Sporulation Nonsporulating TAS [1] cis-1,2-dichloroethene, trans-1,2-dichloroethene, methylene chloride (dichloromethane), tetrachloroethene, 1,1,1- Temperature 18–42 °C TAS [1] range trichloroethane, or vinyl chloride as electron acceptors [1]. Growth is not supported by acetate, butyrate, citrate, Optimum 32–34 °C TAS [1] temperature ethanol, fructose, fumarate, glucose, lactate, lactose, pH range; 6.0–8.0; 6.5–7.5 TAS [1] methanol, methyl ethyl ketone, propionate, pyruvate, suc- Optimum cinate, or yeast extract in the absence of H2 [1]. Carbon source Not reported Although sufficiently high chlorinated alkane concentra- tions were found to become inhibitory, D. alkenigignens MIGS-6 Habitat Groundwater TAS [1, 2] IP3-3T was shown to reductively dehalogenate 1,2-dichloro- MIGS-6.3 Salinity <2 % NaCl (w/v) TAS [1] ethane, 1,2-dichloropropane, and 1,1,2-trichloroethane MIGS-22 Oxygen Obligate anaerobic TAS [1] when present at initial aqueous-phase concentrations as requirement high as 9.81 ± 0.98, 5.05 ± .29, and 3.49 ± 0.31 mM, re- MIGS-15 Biotic Free-living NAS spectively [4]. When grown in the presence of mixtures relationship of chlorinated alkanes, preferential dechlorination of MIGS-14 Pathogenicity Non-pathogen NAS 1,1,2-trichloroethane over both 1,2-dichloroethane and MIGS-4 Geographic Louisiana, USA TAS [1] 1,2-dichloropropane was observed [3]. 1,2-Dichloroethane in location particular was not dechlorinated until 1,1,2-trichloroethane MIGS-5 Sample 2009 IDA reached low concentrations. In contrast, D. alkenigignens collection IP3-3T concurrently dechlorinated 1,2-dichloroethane and MIGS-4.1 Latitude 30.590270 TAS [1] 1,2-dichloropropane over a comparably large concentra- MIGS-4.2 Longitude −91.221288 TAS [1] tion range [3]. MIGS-4.4 Altitude 22 m IDA a Evidence codes - IDA: Inferred from Direct Assay; TAS: Traceable Author Chemotaxonomic data Statement (i.e., a direct report exists in the literature); NAS: Non-traceable The major cellular fatty acids of D. alkenigignens IP3-3T Author Statement (i.e., not directly observed for the living, isolated sample, but based on a generally accepted property for the species, or anecdotal are C18:1 ω9c, C16:0,C14:0,andC16:1 ω9c [1]. The same evidence). These evidence codes are from the Gene Ontology project [59] fatty acids were also present in the closely related D. alke- nigignens strain SBP-1 [1]. Cellular fatty acids present in lower proportions include C18:0,C18:3 ω6c(6,9,12), and un- extinction approach. Growth of the strain was not ob- identified fatty acids with equivalent chain lengths of served on agar plates even after long term (2 months) 11.980, 13.768, 13.937, and 15.056 [1]. incubation [1]. The temperature range for growth of strain IP3-3T is between 18 °C and 42 °C with an Genome sequencing information optimum between 30 °C and 34 °C [1]. The pH range Genome project history for growth is 6.0 to 8.0 with an optimum of 7.0 to 7.5 D. alkenigignens IP3-3T was chosen for genome sequen- [1]. The strain grows in the presence of <2 % (w/v) NaCl cing because it is the type strain of the species and Key et al. Standards in Genomic Sciences (2016) 11:44 Page 3 of 11 Fig. 1 Phylogenetic tree showing the position of D. alkenigignens IP3-3T (shown in bold) relative to the other species of the genus Dehalogenimonas and type species of other genera within the phylum Chloroflexi. The tree was inferred from 1392 aligned nucleotide positions of the 16S rRNA gene sequence using the Neighbor-Joining method within the MEGA v4.0.2 package [60]. Scale bar represents 2 substitutions per 100 nucleotide positions. Numbers at branching points denote support values from 1000 bootstrap replicates if larger than 70 %. Lineages with published genomes are: Anaerolinea thermophila UNI-1T (AP012029),