First Report of Pectobacterium polaris Causing Soft Rot and Black Leg of Potato in Russia.

Blackleg and soft rot of potato (Solanum tuberosum) were monitored in the Central European part of Russia within a period of 2012- 2019. Symptoms included decay of tubers, blackening of stem vascular bundles, and partial yellowing of leaves. The disease causes serious potato yield losses in the field and storage. Pectobacterium parmentieri, P. brasiliense, P. versatile (syn. Ca. Pectobacterium maceratum), P. carotovorum, P. atrosepticum, Dickeya dianthicola, and D. solani are considered as main causal agents of soft rot and blackleg disease in Russia (Voronina et al. 2019, Ngoc Ha et al., 2019, Shirshikov et al. 2018, Kornev et al. 2012). Potato plant samples collected in commercial fields in routine plant health assay were used for bacteria isolation on crystal violet pectate agar (CVP) (Helias et al. 2012) as described previously (Voronina et al. 2019). Bacterial colonies producing pitting on CVP were re-isolated and purified on nutrient broth yeast extract medium. DNA of bacterial isolates was extracted, and polymerase chain reaction (PCR) amplifications were performed using gapA primers (Cigna et al. 2017) followed by sequencing. DNA sequence alignment showed that the isolates F099, F100, F106, F109, and F118 were identical (deposited as part of NCBI Ref.Seq. for F109 NZ_RRYS01000004.1, locus KHDHEBDM_RS06360) and grouped together with the type strain Pectobacterium polaris NIBIO1006T (CP017481), a new species described as a potato pathogen (Dees et al. 2017). These strains were negative in diagnostic PCR assays using specific primers Y45/Y46 for the detection of P. atrosepticum, Br1f and L1r for P. brasiliense (Duarte et al. 2004), and ADE1/ADE2 for Dickeya sp. (Nassar et al. 1996). To further validate the identification, strain F109 of P. polaris was selected for genome sequencing. The genome of P. polaris strain F109, (NCBI Reference Sequence NZ_RRYS00000000.1) reveals >99% sequence similarity with type strain P. polaris IPO_1606 (GenBank accession GCA_902143345.1). The strain F109 was deposited to All-Russian Collection of Microorganisms under number VKM V-3420. Thus, the characterization of five isolates provided evidence that a previously unreported pathogen was present in the surveyed fields. The isolates were uniform in genetic and physiological properties; they were gram negative, facultative anaerobes with pectinolytic activity, negative for oxidase, urease, indole production, gelatin liquefaction. All isolates were catalase positive, produced acid from lactose, rhamnose, saccharose, xylose, and trehalose, and were tolerant to 5% NaCl, unable to utilize malonate and citrate. All the isolates grew at 37°C. All isolates caused soft rot symptoms on 10 inoculated potato tubers. They produced typical black leg rot symptoms in young potato plants inoculated with 107 CFU/ml of the pathogen by stem injection and incubated at 25°C for 48 h. The bacteria were re-isolated successfully from symptomatic potato and pathogen confirmed by gapA sequencing to complete Koch's postulates. To our knowledge, this is the first report of blackleg and soft rot caused by P. polaris on potato in the Russian Federation. According to the data of commercial diagnostic laboratory "PhytoEngineering" (Moscow region), P. polaris occurred in 5% potato seed stocks harvested in 2017-2019 in the Moscow region. This finding may indicate that new Pectobacterium strains have adapted to a diverse environment, which is consistent with widespread distribution of commercial seed potatoes. The author(s) declare no conflict of interest. Funding: This work was supported by Russian Science Foundation grant #16-16-00073.

Tepidibacillus infernus sp. nov., a moderately thermophilic, selenate- and arsenate-respiring hydrolytic bacterium isolated from a gold mine, and emended description of the genus Tepidibacillus.

A novel aerotolerant anaerobic, moderately thermophilic, organotrophic bacterium, strain MBL-TLPT, was isolated from a sample of microbial mat, developed under the flow of subsurface water in TauTona gold mine, South Africa. Cells of the new isolate were flagellated, spore-forming rods, 0.25-0.5 µm in width and 3-15 µm in length. Strain MBL-TLPT grew in the temperature range from 25 to 58 °C, pH range from 5.6 to 8.8 and at NaCl concentration from 0 to 85 g l-1. The isolate was able to ferment yeast extract and mono-, oligo- and polysaccharides, including starch and xanthan gum. The G+C content of the DNA was 35 mol%. Phylogenetic analysis of 16S rRNA gene sequences of strain MBL-TLPT and relatives showed its affiliation to the genus Tepidibacillus. Tepidibacillus fermentans STGHT was its closest relative (97.1 % identity of 16S rRNA gene sequences). Based on phylogenetic analysis and the physiological properties of the novel isolate, we propose a novel species, Tepidibacillus infernus sp. nov., with MBL-TLPT(=DSM 28123T=VKM В-2949T) as the type strain.

Metagenomic profiling of viral and microbial communities from the pox lesions of lumpy skin disease virus and sheeppox virus-infected hosts.

Introduction: It has been recognized that capripoxvirus infections have a strong cutaneous tropism with the manifestation of skin lesions in the form of nodules and scabs in the respective hosts, followed by necrosis and sloughing off. Considering that the skin microbiota is a complex community of commensal bacteria, fungi and viruses that are influenced by infections leading to pathological states, there is no evidence on how the skin microbiome is affected during capripoxvirus pathogenesis. Methods: In this study, shotgun metagenomic sequencing was used to investigate the microbiome in pox lesions from hosts infected with lumpy skin disease virus and sheep pox virus. Results: The analysis revealed a high degree of variability in bacterial community structures across affected skin samples, indicating the importance of specific commensal microorganisms colonizing individual hosts. The most common and abundant bacteria found in scab samples were Fusobacterium necrophorum, Streptococcus dysgalactiae, Helcococcus ovis and Trueperella pyogenes, irrespective of host. Bacterial reads belonging to the genera Moraxella, Mannheimia, Corynebacterium, Staphylococcus and Micrococcus were identified. Discussion: This study is the first to investigate capripox virus-associated changes in the skin microbiome using whole-genome metagenomic profiling. The findings will provide a basis for further investigation into capripoxvirus pathogenesis. In addition, this study highlights the challenge of selecting an optimal bioinformatics approach for the analysis of metagenomic data in clinical and veterinary practice. For example, direct classification of reads using a kmer-based algorithm resulted in a significant number of systematic false positives, which may be attributed to the peculiarities of the algorithm and database selection. On the contrary, the process of de novo assembly requires a large number of target reads from the symbiotic microbial community. In this work, the obtained sequencing data were processed by three different approaches, including direct classification of reads based on k-mers, mapping of reads to a marker gene database, and de novo assembly and binning of metagenomic contigs. The advantages and disadvantages of these techniques and their practicality in veterinary settings are discussed in relation to the results obtained.

Evolutionary patterns of archaea predominant in acidic environment.

BACKGROUND: Archaea of the order Thermoplasmatales are widely distributed in natural acidic areas and are amongst the most acidophilic prokaryotic organisms known so far. These organisms are difficult to culture, with currently only six genera validly published since the discovery of Thermoplasma acidophilum in 1970. Moreover, known great diversity of uncultured Thermoplasmatales represents microbial dark matter and underlines the necessity of efforts in cultivation and study of these archaea. Organisms from the order Thermoplasmatales affiliated with the so-called "alphabet-plasmas", and collectively dubbed "E-plasma", were the focus of this study. These archaea were found predominantly in the hyperacidic site PM4 of Parys Mountain, Wales, UK, making up to 58% of total metagenomic reads. However, these archaea escaped all cultivation attempts. RESULTS: Their genome-based metabolism revealed its peptidolytic potential, in line with the physiology of the previously studied Thermoplasmatales isolates. Analyses of the genome and evolutionary history reconstruction have shown both the gain and loss of genes, that may have contributed to the success of the "E-plasma" in hyperacidic environment compared to their community neighbours. Notable genes among them are involved in the following molecular processes: signal transduction, stress response and glyoxylate shunt, as well as multiple copies of genes associated with various cellular functions; from energy production and conversion, replication, recombination, and repair, to cell wall/membrane/envelope biogenesis and archaella production. History events reconstruction shows that these genes, acquired by putative common ancestors, may determine the evolutionary and functional divergences of "E-plasma", which is much more developed than other representatives of the order Thermoplasmatales. In addition, the ancestral hereditary reconstruction strongly indicates the placement of Thermogymnomonas acidicola close to the root of the Thermoplasmatales. CONCLUSIONS: This study has analysed the metagenome-assembled genome of "E-plasma", which denotes the basis of their predominance in Parys Mountain environmental microbiome, their global ubiquity, and points into the right direction of further cultivation attempts. The results suggest distinct evolutionary trajectories of organisms comprising the order Thermoplasmatales, which is important for the understanding of their evolution and lifestyle.

The Baltic Sea methane pockmark microbiome: The new insights into the patterns of relative abundance and ANME niche separation.

Pockmarks are important "pumps", which are believed to play a significant role in the global methane cycling and harboring a unique assemblage of very diverse prokaryotes. This study reports the results of massive sequencing of the 16S rRNA gene V4 hypervariable regions for the samples from thirteen pockmark horizons (the Baltic Sea) collected at depths from 0 to 280 cm below seafloor (cmbsf) and the rates of microbially mediated anaerobic oxidation of methane (AOM) and sulfate reduction (SR). Altogether, 76 bacterial and 12 archaeal phyla were identified, 23 of which were candidate divisions. Of the total obtained in the pockmark sequences, 84.3% of them were classified as Bacteria and 12.4% as Archaea; 3.3% of the sequences were assigned to unknown operational taxonomic units (OTUs). Members of the phyla Planctomycetota, Chloroflexota, Desulfobacterota, Caldatribacteriota, Acidobacteriota and Proteobacteria predominated across all horizons, comprising 58.5% of the total prokaryotic community. These phyla showed different types of patterns of relative abundance. Analysis of AOM-SR-mediated prokaryotes abundance and biogeochemical measurements revealed that ANME-2a-2b subcluster was predominant in sulfate-rich upper horizons (including sulfate-methane transition zone (SMTZ)) and together with sulfate-reducing bacterial group SEEP-SRB1 had a primary role in AOM coupled to SR. At deeper sulfate-depleted horizons ANME-2a-2b shifted to ANME-1a and ANME-1b which alone mediated AOM or switch to methanogenic metabolism. Shifting of the ANME subclusters depending on depth reflect a tendency for niche separation in these groups. It was shown that the abundance of Caldatribacteriota and organohalide-respiring Dehalococcoidia (Chloroflexota) exhibited a strong correlation with AOM rates. This is the first detailed study of depth profiles of prokaryotic diversity, patterns of relative abundance, and ANME niche separation in the Baltic Sea pockmark microbiomes sheds light on assembly of prokaryotes in a pockmark.

Nitrogen Fixation Activity and Genome Analysis of a Moderately Haloalkaliphilic Anoxygenic Phototrophic Bacterium Rhodovulum tesquicola.

The genome of the moderately haloalkaliphilic diazotrophic anoxygenic phototrophic bacterium Rhodovulum tesquicola A-36sT isolated from an alkaline lake was analyzed and compared to the genomes of the closest species Rhodovulum steppense A-20sT and Rhodovulum strictum DSM 11289T. The genomic features of three organisms are quite similar, reflecting their ecological and physiological role of facultative photoheterotrophs. Nevertheless, the nitrogenase activity of the pure cultures of the studied bacteria differed significantly: the highest rate (4066 nmoles C2H2/mg of dry weight per hour) was demonstrated by Rhodovulum strictum while the rates in Rhodovulum tesquicola and Rhodovulum steppense were an order of magnitude lower (278 and 523 nmoles C2H2/mg of dry weight per hour, respectively). This difference can be attributed to the presence of an additional nitrogenase operon found exclusively in R. strictum and to the structural variation in nitrogenase operon in R. tesquicola.

Draft Genome Sequence of Rhodococcus qingshengii (Formerly erythropolis) TA37, a First-Generation Biocatalyst for Synthesis of Functionalized Acrylamides.

We describe here the 7.0-Mb draft genome sequence of Rhodococcus qingshengii strain TA37, which was obtained from samples of nitrile-contaminated soil collected in the Saratov Region (Russian Federation). This genomic resource will support the further development of biocatalysts for the inexpensive and green production of acrylic monomers.

A dataset of four probiotic Bifidobacterium strains genome assemblies.

A dataset of four draft genome sequences of Bifidobacterium strains is presented. All four genome assemblies are high-quality drafts characterized by high completeness and low contamination levels. GC content of the genomes varied in the range between 59.27% and 62.77%. Genome sequences were annotated for further functional and taxonomical analyses of the respective Bifidobacterium strains. Genetic determinants of probiotic capabilities, including the genes, related to utilization of human milk oligosaccharides and mucin, as well as the genes, encoding bile salt hydrolase were identified. The genome of B. bifidum VKPM=Ac-1784 has been shown to possess two bacteriocin gene clusters. The dataset expands knowledge on genomic diversity of probiotic strains of Bifidobacterium genus. The dataset is available under PRJNA656137 accession number in NCBI database and under zyv26t6x5r accession number in Mendeley Data repository.

Draft Genome Sequence of Rhodococcus erythropolis HX7, a Psychrotolerant Soil-Derived Oil Degrader.

We describe here a 6.6-Mb draft genome sequence of Rhodococcus erythropolis strain HX7, which was obtained from soil samples collected from the northern Arkhangelsk region in the Russian Federation. This genomic resource will support further study of mechanisms of cold-resistant oil degradation in soil and potentially aid in soil bioremediation in cold oil-producing regions.

Culture-Independent Survey of Thermophilic Microbial Communities of the North Caucasus.

The Greater Caucasus is a part of seismically active Alpine-Himalayan orogenic belt and has been a center of significant volcanic activity during the Quaternary period. That led to the formation of the number of hydrothermal habitats, including subterranean thermal aquifers and surface hot springs. However, there are only a limited number of scientific works reporting on the microbial communities of these habitats. Moreover, all these reports concern only studies of specific microbial taxa, carried out using classical cultivation approaches. In this work, we present first culture-independent study of hydrotherms in the Republic of North Ossetia-Alania, located in the southern part of the North Caucasus. Using 16S metabarcoding, we analyzed the composition of the microbial communities of two subterranean thermal aquifers and terrestrial hot springs of the Karmadon valley. Analysis of correlations between the chemical composition of water and the representation of key taxa allowed us to identify the key factors determining the formation of microbial communities. In addition, we were able to identify a significant number of highly abundant deep phylogenetic lineages. Our study represents a first glance on the thermophilic microbial communities of the North Caucasus and may serve as a basis for further microbiological studies of the extreme habitats of this region.

Utilization of low-molecular-weight organic compounds by the filterable fraction of a lotic microbiome.

Filterable microorganisms participate in dissolved organic carbon (DOC) cycling in freshwater systems, however their exact functional role remains unknown. We determined the taxonomic identity and community dynamics of prokaryotic microbiomes in the 0.22 µm-filtered fraction and unfiltered freshwater from the Conwy River (North Wales, UK) in microcosms and, using targeted metabolomics and 14C-labelling, examined their role in the utilization of amino acids, organic acids and sugars spiked at environmentally-relevant (nanomolar) concentrations. To identify changes in community structure, we used 16S rRNA amplicon and shotgun sequencing. Unlike the unfiltered water samples where the consumption of DOC was rapid, the filtered fraction showed a 3-day lag phase before the consumption started. Analysis of functional categories of clusters of orthologous groups of proteins (COGs) showed that COGs associated with energy production increased in number in both fractions with substrate addition. The filtered fraction utilized low-molecular-weight (LMW) DOC at much slower rates than the whole community. Addition of nanomolar concentrations of LMW DOC did not measurably influence the composition of the microbial community nor the rate of consumption across all substrate types in either fraction. We conclude that due to their low activity, filterable microorganisms play a minor role in LMW DOC processing within a short residence time of lotic freshwater systems.

Origin and Evolution of Studiervirinae Bacteriophages Infecting Pectobacterium: Horizontal Transfer Assists Adaptation to New Niches.

Black leg and soft rot are devastating diseases causing up to 50% loss of potential potato yield. The search for, and characterization of, bacterial viruses (bacteriophages) suitable for the control of these diseases is currently a sought-after task for agricultural microbiology. Isolated lytic Pectobacterium bacteriophages Q19, PP47 and PP81 possess a similar broad host range but differ in their genomic properties. The genomic features of characterized phages have been described and compared to other Studiervirinae bacteriophages. Thorough phylogenetic analysis has clarified the taxonomy of the phages and their positioning relative to other genera of the Autographiviridae family. Pectobacterium phage Q19 seems to represent a new genus not described previously. The genomes of the phages are generally similar to the genome of phage T7 of the Teseptimavirus genus but possess a number of specific features. Examination of the structure of the genes and proteins of the phages, including the tail spike protein, underlines the important role of horizontal gene exchange in the evolution of these phages, assisting their adaptation to Pectobacterium hosts. The results provide the basis for the development of bacteriophage-based biocontrol of potato soft rot as an alternative to the use of antibiotics.

Co-occurrence patterns of bacteria within microbiome of Moscow subway.

Microbial ecosystems of the built environments have become key mediators of health as people worldwide tend to spend large amount of time indoors. Underexposure to microbes at an early age is linked to increased risks of allergic and autoimmune diseases. Transportation systems are of particular interest, as they are globally the largest space for interactions between city-dwellers. Here we performed the first pilot study of the Moscow subway microbiome by analyzing swabs collected from 5 types of surfaces at 4 stations using high-throughput 16S rRNA gene sequencing. The study was conducted as a part of The Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) project. The most abundant microbial taxa comprising the subway microbiome originated from soil and human skin. Microbiome diversity was positively correlated with passenger traffic. No substantial evidence of major human pathogens presence was found. Co-occurrence analysis revealed clusters of microbial genera including combinations of microbes likely originating from different niches. The clusters as well as the most abundant microbes were similar to ones obtained for the published data on New-York City subway microbiome. Our results suggest that people are the main source and driving force of diversity in subway-associated microbiome. The data form a basis for a wider survey of Moscow subway microbiome to explore its longitudinal dynamics by analyzing an extended set of sample types and stations. Complementation of methods with viability testing, "shotgun" metagenomics, sequencing of bacterial isolates and culturomics will provide insights for public health, biosafety, microbial ecology and urban design.

Archaea dominate the microbial community in an ecosystem with low-to-moderate temperature and extreme acidity.

BACKGROUND: The current view suggests that in low-temperature acidic environments, archaea are significantly less abundant than bacteria. Thus, this study of the microbiome of Parys Mountain (Anglesey, UK) sheds light on the generality of this current assumption. Parys Mountain is a historically important copper mine and its acid mine drainage (AMD) water streams are characterised by constant moderate temperatures (8-18 °C), extremely low pH (1.7) and high concentrations of soluble iron and other metal cations. RESULTS: Metagenomic and SSU rRNA amplicon sequencing of DNA from Parys Mountain revealed a significant proportion of archaea affiliated with Euryarchaeota, which accounted for ca. 67% of the community. Within this phylum, potentially new clades of Thermoplasmata were overrepresented (58%), with the most predominant group being "E-plasma", alongside low-abundant Cuniculiplasmataceae, 'Ca. Micrarchaeota' and 'Terrestrial Miscellaneous Euryarchaeal Group' (TMEG) archaea, which were phylogenetically close to Methanomassilicoccales and clustered with counterparts from acidic/moderately acidic settings. In the sediment, archaea and Thermoplasmata contributed the highest numbers in V3-V4 amplicon reads, in contrast with the water body community, where Proteobacteria, Nitrospirae, Acidobacteria and Actinobacteria outnumbered archaea. Cultivation efforts revealed the abundance of archaeal sequences closely related to Cuniculiplasma divulgatum in an enrichment culture established from the filterable fraction of the water sample. Enrichment cultures with unfiltered samples showed the presence of Ferrimicrobium acidiphilum, C. divulgatum, 'Ca. Mancarchaeum acidiphilum Mia14', 'Ca. Micrarchaeota'-related and diverse minor (< 2%) bacterial metagenomic reads. CONCLUSION: Contrary to expectation, our study showed a high abundance of archaea in this extremely acidic mine-impacted environment. Further, archaeal populations were dominated by one particular group, suggesting that they are functionally important. The prevalence of archaea over bacteria in these microbiomes and their spatial distribution patterns represents a novel and important advance in our understanding of acidophile ecology. We also demonstrated a procedure for the specific enrichment of cell wall-deficient members of the archaeal component of this community, although the large fraction of archaeal taxa remained unculturable. Lastly, we identified a separate clustering of globally occurring acidophilic members of TMEG that collectively belong to a distinct order within Thermoplasmata with yet unclear functional roles in the ecosystem.

Diversity of "Ca. Micrarchaeota" in Two Distinct Types of Acidic Environments and Their Associations with Thermoplasmatales.

"Candidatus Micrarchaeota" are widely distributed in acidic environments; however, their cultivability and our understanding of their interactions with potential hosts are very limited. Their habitats were so far attributed with acidic sites, soils, peats, freshwater systems, and hypersaline mats. Using cultivation and culture-independent approaches (16S rRNA gene clonal libraries, high-throughput amplicon sequencing of V3-V4 region of 16S rRNA genes), we surveyed the occurrence of these archaea in geothermal areas on Kamchatka Peninsula and Kunashir Island and assessed their taxonomic diversity in relation with another type of low-pH environment, acid mine drainage stream (Wales, UK). We detected "Ca. Micrarchaeota" in thermophilic heterotrophic enrichment cultures of Kunashir and Kamchatka that appeared as two different phylotypes, namely "Ca. Mancarchaeum acidiphilum"-, and ARMAN-2-related, alongside their potential hosts, Cuniculiplasma spp. and other Thermoplasmatales archaea without defined taxonomic position. These clusters of "Ca. Micrarchaeota" together with three other groups were also present in mesophilic acid mine drainage community. Present work expands our knowledge on the diversity of "Ca. Micrarchaeota" in thermophilic and mesophilic acidic environments, suggests cultivability patterns of acidophilic archaea and establishes potential links between low-abundance species of thermophilic "Ca. Micrarchaeota" and certain Thermoplasmatales, such as Cuniculiplasma spp. in situ.

Microbial Communities of Polymetallic Deposits' Acidic Ecosystems of Continental Climatic Zone With High Temperature Contrasts.

Acid mine drainage (AMD) systems are globally widespread and are an important source of metal pollution in riverine and coastal systems. Microbial AMD communities have been extensively studied for their ability to thrive under extremely acidic conditions and for their immense contribution to the dissolution of metal ores. However, little is known on microbial inhabitants of AMD systems subjected to extremely contrasting continental seasonal temperature patterns as opposed to maritime climate zones, experiencing much weaker annual temperature variations. Here, we investigated three types of AMD sites in Eastern Transbaikalia (Russia). In this region, all surface water bodies undergo a deep and long (up to 6 months) freezing, with seasonal temperatures varying between -33 and +24°C, which starkly contrasts the common well-studied AMD environments. We sampled acidic pit lake (Sherlovaya Gora site) located in the area of a polymetallic deposit, acidic drainage water from Bugdaya gold-molybdenum-tungsten deposit and Ulan-Bulak natural acidic spring. These systems showed the abundance of bacteria-derived reads mostly affiliated with Actinobacteria, Acidobacteria, Alpha- and Gammaproteobacteria, chloroplasts, Chloroflexi, Bacteroidetes, and Firmicutes. Furthermore, candidate taxa "Ca. Saccharibacteria" (previously known as TM7), "Ca. Parcubacteria" (OD1) and WPS-2 were represented in substantial quantities (10-20%). Heterotrophy and iron redox cycling can be considered as central processes of carbon and energy flow for majority of detected bacterial taxa. Archaea were detected in low numbers, with Terrestrial Miscellaneous Euryarchaeal Group (TMEG), to be most abundant (3%) in acidic spring Ulan-Bulak. Composition of these communities was found to be typical in comparison to other AMD sites; however, certain groups (as Ignavibacteriae) could be specifically associated with this area. This study provides insight into the microbial diversity patterns in acidic ecosystems formed in areas of polymetallic deposits in extreme continental climate zone with contrasting temperature parameters.

Draft Genome Sequence of Methylovulum psychrotolerans Sph1T, an Obligate Methanotroph from Low-Temperature Environments.

Methylovulum psychrotolerans Sph1T is an aerobic, obligate methanotroph, which was isolated from cold methane seeps in West Siberia. This bacterium possesses only a particulate methane monooxygenase and is widely distributed in low-temperature environments. Strain Sph1T has the genomic potential for biosynthesis of hopanoids required for the maintenance of intracytoplasmic membranes.

Draft Genome Sequence of Pectobacterium atrosepticum PB72 and Complete Genome Sequence of the Specific Bacteriophage PP90.

We present the draft genome sequence of Pectobacterium atrosepticum strain PB72 infecting potatoes in Russia. PB72 is similar to the previously reported strain 21A. Considering potential biocontrol of this pathogen, an infectious bacteriophage was isolated and characterized. Phage vB_PatP_PP90 is a lytic podovirus of narrow host range belonging to the KP34virus genus.

Draft Genome Sequences of New Genomospecies "Candidatus Pectobacterium maceratum" Strains, Which Cause Soft Rot in Plants.

Investigation of collections of phytopathogenic bacteria has revealed some strains distinct from known Pectobacterium spp. We report here the draft genome sequences of five such strains, isolated during the period of 1947 to 2012. Based on comparative genomics, we propose a new candidate genomospecies of the genus Pectobacterium, "Candidatus Pectobacterium maceratum."

Host Specificity of the Dickeya Bacteriophage PP35 Is Directed by a Tail Spike Interaction With Bacterial O-Antigen, Enabling the Infection of Alternative Non-pathogenic Bacterial Host.

Dickeya solani is a recently emerged virulent bacterial potato pathogen that poses a major threat to world agriculture. Because of increasing antibiotic resistance and growing limitations in antibiotic use, alternative antibacterials such as bacteriophages are being developed. Myoviridae bacteriophages recently re-ranked as a separate Ackermannviridae family, such as phage PP35 described in this work, are the attractive candidates for this bacterial biocontrol. PP35 has a very specific host range due to the presence of tail spike protein PP35 gp156, which can depolymerize the O-polysaccharide (OPS) of D. solani. The D. solani OPS structure, →2)-ß-D-6-deoxy-D-altrose-(1→, is so far unique among soft-rot Pectobacteriaceae, though it may exist in non-virulent environmental Enterobacteriaceae. The phage tail spike depolymerase degrades the shielding polysaccharide, and launches the cell infection process. We hypothesize that non-pathogenic commensal bacteria may maintain the population of the phage in soil environment.