Bacteriophage GC1, a Novel Tectivirus Infecting Gluconobacter Cerinus, an Acetic Acid Bacterium Associated with Wine-Making

Abstract

The Gluconobacter phage GC1 is a novel member of the Tectiviridae family isolated from a juice sample collected during dry white wine making. The bacteriophage infects Gluconobacter cerinus, an acetic acid bacterium which represents a spoilage microorganism during wine making, mainly because it is able to produce ethyl alcohol and transform it into acetic acid. Transmission electron microscopy revealed tail-less icosahedral particles with a diameter of ~78 nm. The linear double-stranded DNA genome of GC1 (16,523 base pairs) contains terminal inverted repeats and carries 36 open reading frames, only a handful of which could be functionally annotated. These encode for the key proteins involved in DNA replication (protein-primed family B DNA polymerase) as well as in virion structure and assembly (major capsid protein, genome packaging ATPase (adenosine triphosphatase) and several minor capsid proteins). GC1 is the first tectivirus infecting an alphaproteobacterial host and is thus far the only temperate tectivirus of gram-negative bacteria. Based on distinctive sequence and life-style features, we propose that GC1 represents a new genus within the Tectiviridae, which we tentatively named “Gammatectivirus”. Furthermore, GC1 helps to bridge the gap in the sequence space between alphatectiviruses and betatectiviruses.

Bacteriophages as an Up-and-Coming Alternative to the Use of Sulfur Dioxide in Winemaking

“…Viral genetic material extraction achieved high concentrations, so it was the basis for deducing that the bacteriophages were constituted of DNA. Visualization by electronic microscopy with DNA extraction allowed the phages to be classified as double-stranded DNA, matching the majority of previous studies of wine or vinegar bacteriophages (Davis et al, 1985;Henick-Kling et al, 1986a,b;Hernández-Magadán, 2007;Dini, 2011Philippe et al, 2018. Despite EcoRI, EcoRV, HinfI, and HindIII endonucleases having been used in similar studies of bacteriophages in dairy products and wine (Moineau et al, 1993;Ackermann, 1998;Spricigo et al, 2013), in our study, the RFLP analysis showed that these enzymes did not digest the genome of the phages isolated.…”

“…On the other hand, the phages that infected O. oeni belonged to the Tectiviridae family within the polyhedral phages. Although tectiviruses usually infect enteric species, bacilli, and species of the Thermus genus, previous studies have already demonstrated the existence of this family of viruses in wine, such as bacteriophage GC1, a new tectivirus that infects Gluconobacter cerinus in dry white wine-making (Ackermann and DuBow, 1987;Philippe et al, 2018).…”

“…When agar was needed, 1.5% w/v (nutritive) and 0.75% w/v (layer) of agar was dissolved in 1 l of distilled water. The most recommended culture medium is GYC, in which the main compound is calcium carbonate, used to give opacity (Bordons and Reguant, 2013;Philippe et al, 2018). This opacity enables the bacterial growth to be monitored, as the microorganism dissolves carbonate when colonies are developed, producing holes or differently colored areas in the plate.…”

A Novel Genus of Actinobacterial Tectiviridae

“…Having established distant orthology with proteins in other Tectiviridae genomes, we assessed the apparent similarity in genome organization between Rhodococcus phage Toil and Streptomyces phages WheeHeim and Forthebois in the broader context of Tectiviridae genome architecture. The genome maps displayed in Figure 4 reveal the previously noted structural genome similarity among the three established tectiviral genera [16], and show that this structural similarity extends to the Rhodococcus and Streptomyces phages. All genomes contain a first genomic segment that appears to have switched orientation in multiple instances, with the family B DNA polymerase as its only identifiable conserved element.…”

“…Members of the Betatectivirus genus replicate independently of the host chromosome as linear plasmids and regulate transition to a lytic lifestyle via the host SOS transcription repressor LexA [15]. The Gammatectivirus genus contains only one known member, Gluconobacter phage GC1, which is also temperate and infects the Alphaproteobacterium Gluconobacter cerinus [16].…”