Characterization of a new virulent phage infecting the lactic acid bacterium Oenococcus oeni

Krupovìč

et al. 2018

Viruses

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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.

Section: Methodsmentioning

confidence: 99%

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

Krupovìč

et al. 2018

Viruses

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“…Phage OE33PA (vB_OeS_OE33PA) was recently isolated from a red wine using O. oeni host strain IOEBS277 ( 10 ). Its apparent obligately lytic lifestyle was intriguing since most oenophages reported to date are temperate ( 11 ).…”

Section: Announcementmentioning

confidence: 99%

Complete Genome Sequence of Lytic Oenococcus oeni Bacteriophage OE33PA

Claisse

Microbiol Resour Announc

et al. 2018

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“…Their functional homogeneity indexes were 0.76, 0.86, 0.82, and 0.76, respectively. None of the corresponding genes were located in the rightward module containing moron genes (19,20,31) (Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

“…To test this, RGJ agar plates were spread in duplicate with serial dilutions of a culture of the sensitive strain IOEBS277. One plate was further air sprayed with the virulent oenophage OE33PA (31,32), while the control was kept uninfected. After incubation, we observed a transition from white to red morphotype for most colonies (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Lysogeny in the Lactic Acid Bacterium Oenococcus oeni Is Responsible for Modified Colony Morphology on Red Grape Juice Agar

Chaïb

et al. 2019

Appl Environ Microbiol

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Oenococcus oeni is the lactic acid bacterium (LAB) that most commonly drives malolactic fermentation in wine. Although oenococcal prophages are highly prevalent, their implications on bacterial fitness have remained unexplored and more research is required in this field. An important step toward achieving this goal is the ability to produce isogenic pairs of strains that differ only by the lysogenic presence of a given prophage, allowing further comparisons of different phenotypic traits. A novel protocol for the rapid isolation of lysogens is presented. Bacteria were first picked from the center of turbid plaques produced by temperate oenophages on a sensitive nonlysogenic host. When streaked onto an agar medium containing red grape juice (RGJ), cells segregated into white and red colonies. PCR amplifications with phage-specific primers demonstrated that only lysogens underwent white-red morphotypic switching. The method proved successful for various oenophages irrespective of their genomic content and attachment site used for site-specific recombination in the bacterial chromosome. The color switch was also observed when a sensitive nonlysogenic strain was infected with an exogenously provided lytic phage, suggesting that intracolonial lysis triggers the change. Last, lysogens also produced red colonies on white grape juice agar supplemented with polyphenolic compounds. We posit that spontaneous prophage excision produces cell lysis events in lysogenic colonies growing on RGJ agar, which, in turn, foster interactions between lysed materials and polyphenolic compounds to yield colonies easily distinguishable by their red color. Furthermore, the technique was used successfully with other species of LAB. IMPORTANCE The presence of white and red colonies on red grape juice (RGJ) agar during enumeration of Oenococcus oeni in wine samples is frequently observed by stakeholders in the wine industry. Our study brings an explanation for this intriguing phenomenon and establishes a link between the white-red color switch and the lysogenic state of O. oeni. It also provides a simple and inexpensive method to distinguish between lysogenic and nonlysogenic derivatives in O. oeni with a minimum of expended time and effort. Noteworthy, the protocol could be adapted to two other species of LAB, namely, Leuconostoc citreum and Lactobacillus plantarum. It could be an effective tool to provide genetic, ecological, and functional insights into lysogeny and aid in improving biotechnological processes involving members of the lactic acid bacterium (LAB) family.