Vol.:(0123456789) 1 3 Archives of Virology https://doi.org/10.1007/s00705-020-04780-7 ANNOTATED SEQUENCE RECORD Complete genome sequence of Buttiauxella phage vB_ButM_GuL6 Algirdas Noreika 1  · Rolandas Meškys 1  · Justas Lazutka 2  · Laura Kaliniene 1 Received: 16 June 2020 / Accepted: 20 July 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020 Abstract We present here the results of the analysis of the complete genome sequence of a lytic bacteriophage, vB_ButM_GuL6, which is the frst virus isolated from Buttiauxella. Electron microscopy revealed that vB_ButM_GuL6 belongs to the fam- ily Myoviridae, order Caudovirales. The genome of vB_ButM_GuL6 is a linear, circularly permuted 178,039-bp dsDNA molecule with a GC content of 43.4%. It has been predicted to contain 282 protein-coding genes and two tRNA genes, tRNA-Met and tRNA-Gly. Using bioinformatics approaches, 99 (36%) of the vB_ButM_GuL6 genes were assigned a putative function. Genome-wide comparisons and phylogenetic analysis indicated that vB_ButM_GuL6 represents a new species of the subfamily Tevenvirinae and is most closely related to Escherichia virus RB43. These phages, together with Cronobacter phages Miller, CfP1, and IME-CF2, likely form a new genus within the subfamily Tevenvirinae. The genus Buttiauxella, family Enterobacteriaceae within the class Gammaproteobacteria, includes aerobic and fac- ultatively anaerobic Gram-negative motile rods, which are negative for oxidase. Buttiauxella is widely distributed in nature and is frequently isolated from fresh water, soil, the intestines of snails or slugs, and, occasionally, from human sources [1, 2]. It has been reported that bacteriophages, viruses that infect bacteria, outnumber their bacterial hosts at least tenfold [3]. However, to date, there are no Buttiaux- ella phage genome sequences in the databases. We report here the results of the analysis of the complete genome sequence of a novel bacteriophage, vB_ButM_GuL6 (sub- sequently referred to by its shorter common laboratory name GuL6), isolated using Buttiauxella sp. environmental isolate G6 as a host. Both bacteriophage GuL6 and its host, Buttiauxella sp. isolate G6 (verifed by 16S rRNA sequencing, accession number MT337563), were isolated from windfall hawthorn (Crataegus nigra) berries harvested from a private garden (54° 47’ 23.28’’ N/25° 22’ 59.196’’ E; Vilnius, Lithu- ania). A standard sample enrichment technique was used [4], with incubation at 22 °C. For phage purifcation, bac- teria were cultivated aerobically in LB medium at 37 °C, and the phage was propagated using the soft-agar overlay method [4]. When plated, phage GuL6 formed small, clear plaques (diameter, < 1 mm), indicating a lytic life style. The morphology of CsCl-purifed phage particles was examined using a Morgagni TM 268(D) transmission electron micro- scope (FEI, Oregon, USA) as described previously [5]. TEM micrographs showed that GuL6 has a contractile tail and may belong to the family Myoviridae, order Caudovirales (Supplementary Fig. S1). GuL6 DNA was extracted from a high-titer stock (10 11 –10 12 PFU/ml), using a standard phenol/chloroform extraction and ethanol precipitation method [6], and then sent to BaseClear (Leiden, The Netherlands) for genome sequencing, quality assessment of the sequence reads, and de novo assembly, as described in the Supplementary File. A single viral contig with 3,558-fold coverage was obtained, and the genome sequence was annotated and analyzed using Geneious Prime (v2020.1.2, https://www.geneious. com), tRNAscan-SE [7], BLAST [8], and HHPred [9]. The genome of GuL6 was found to be a linear, circularly per- muted 178,039-bp dsDNA molecule, with a GC content of Handling Editor: Johannes Wittmann. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00705-020-04780-7) contains supplementary material, which is available to authorized users. * Laura Kaliniene laura.kaliniene@bchi.vu.lt 1 Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Vilnius University Life Sciences Center, Saulėtekio av. 7, 10257 Vilnius, Lithuania 2 Department of Eukaryote Gene Engineering, Institute of Biotechnology, Life Sciences Center, Saulėtekio av. 7, 10257 Vilnius, Lithuania