Phytopathogenic bacteria of the genus Pectobacterium are responsible for several diseases that affect potato (Solanum tuberosum L.) production worldwide, including blackleg and tuber soft rot. These bacteria are highly diverse, with over 17 different species currently identified. However, some of the recently described species, such as Pectobacterium punjabense, are still poorly understood. In this study, we focused on P. punjabense isolates collected from diseased potato tubers in Russia in 2021. Whole-genome sequencing was used to characterise the genomic diversity of the pathogen and determine the biochemical profiles of the isolated bacteria. The ability of these isolates to cause soft rot symptoms was tested. A comparative assessment of the potential pathogenicity of the Pectobacterium isolates was conducted by infecting potato tubers and measuring the accumulation of biomass in a liquid medium during cultivation at different temperatures. A TaqMan qPCR assay was developed for the highly sensitive and specific characterisation of P. punjabense strains, which can be used in diagnostic systems. This is the first report on P. punjabense causing potato disease in the Russian Federation.

Phages of phytopathogenic bacteria are considered to be promising agents for the biological control of bacterial diseases in plants. This paper reports on the isolation and characterisation of a new Xanthomonas campestris pv. campestris phage, Murka. Phage morphology and basic kinetic characteristics of the infection were determined, and a phylogenomic analysis was performed. The phage was able to lyse a reasonably broad range (64%, 9 of the 14 of the Xanthomonas campestris pv. campestris strains used in the study) of circulating strains of the cabbage black rot pathogen. This lytic myovirus has a DNA genome of 44,044 bp and contains 83 predicted genes. Taxonomically, it belongs to the genus Foxunavirus. This bacteriophage is promising for use as a possible means of biological control of cabbage black rot.

Antibiotic-resistant Pseudomonas aeruginosa presents a critical global health challenge, particularly in hospital-acquired infections. Bacteriophages offer a promising therapeutic avenue due to their ability to target and lyse resistant strains. This study characterizes Pseudomonas phage Banzai, a newly isolated Pbunavirus (family Lindbergviridae) with lytic activity against multiple P. aeruginosa isolates, including multidrug-resistant strains. Genomic analysis revealed a 66,189 bp genome, lacking antibiotic resistance or virulence factors, and suggested a headful packaging mechanism and the presence of a bidirectional component in the replication. In vivo experiments using Galleria mellonella showed therapeutic potential, significantly improving larval survival (87% at 24 h). Host range analysis revealed activity against 13 of 30 P. aeruginosa isolates, including members of O1, O3, O5 and O6 in silico predicted serogroups. Phylogenomic analyses place phage Banzai within the genus Pbunavirus, sharing 94.8% intergenomic similarity with its closest relatives, supporting its classification as a novel species. These findings highlight phage Banzai as a potential candidate for phage therapy, demonstrating genomic stability, a strictly lytic lifestyle, and in vivo efficacy.

The genus Parabacteroides comprises widespread gastrointestinal commensals, known to produce immunomodulatory molecules and extracellular vesicles, yet its full diversity is incompletely cataloged. This study describes strain ASD2025^T, isolated from healthy child feces, using a polyphasic taxonomic approach including phenotypic profiling, chemotaxonomy, and comparative genomics. Cells were non-motile, polymorphic rods that produced extracellular vesicles. Phylogenomic analysis placed ASD2025^T within the genus Parabacteroides within a species complex consisting of P. acidifaciens, P. hominis, “P. massiliensis”, P. merdae, and P. johnsonii, with average nucleotide identities to the type strains of 85.5–89.9%. The large genome (5.16 Mbp, 46.2% GC content) contained integrative conjugative elements harboring antibiotic resistance genes and hankyphage-related prophage. The strain produced succinate as the major metabolic end product, and its major fatty acids were anteiso-C_15:0, iso-C_17:0 3-OH, and C_15:0. Conditioned medium from ASD2025^T antagonized the interleukin-8 response caused by E. coli lipopolysaccharide in HT29 cells. The majority of related metagenome-assembled genomes originate from mouse microbiomes. Based on these distinct characteristics, strain ASD2025^T (=VKM B-3926^T = JCM 37967^T) represents a novel species of the genus Parabacteroides, for which the name Parabacteroides vesiculifaciens sp. nov. is proposed.

Bacteriophages are powerful drivers of microbial evolution and are increasingly explored as alternatives to antibiotics against multidrug-resistant pathogens such as Pseudomonas aeruginosa. Here, we describe the isolation, phenotypic characterization and genomic, structural and evolutionary analysis of Pseudomonas phage Adele, a lytic myovirus representing a novel species within the genus Pakpunavirus (family Vandenendeviridae). Phage Adele exhibits a short latent period of 20 min, a burst size of 59 ± 11 virions per infected cell and a high virulence index, efficiently lysing non-O11 Pseudomonas aeruginosa strains and reducing biofilm biomass. In vivo, Adele confers marked protection in a Galleria mellonella infection model. Phylogenetic reconstruction, synteny analysis and structural modeling demonstrate the relatedness of Vandenendeviridae to phages of the Andersonviridae and Vequintavirinae clades, pointing to a stable, ancestral virion architecture that has undergone lineage-specific elaborations, including the duplication and divergence of tail tube proteins. The tail assembly chaperone gene employs a conserved −1 programmed ribosomal frameshift. Phage Adele encodes an elaborate set of metabolic reprogramming and anti-defense systems, reflecting extensive horizontal gene transfer. The combination of a conserved structural architecture and mosaic genome establishes Adele as an exemplary system for studying modular evolution in phages, alongside its demonstrated therapeutic efficacy.

Species of the genus Epicoccum are widespread plant-associated fungi; however, their phytopathological significance in soybean remains insufficiently studied. In the present study, 15 Epicoccum isolates obtained in 2024–2026 from symptomatic soybean leaves and seeds in four regions of Russia were characterized using multilocus phylogenetic analysis, whole-genome sequencing, controlled inoculation assays, assessment of extracellular enzymatic activity, and fungicide sensitivity testing. Nine isolates were identified as E. tobaicum, five as E. mezzettii, and one as E. oryzae. The five sequenced genomes ranged from 32.84 to 34.62 Mb in size, with BUSCO completeness of 97.1–98.9%. In the mycelial-plug assay, performed without needle puncturing of the leaf blade, the largest mean necrotic lesion diameter was 12.75 ± 5.03 mm; in a separate wound-assisted assay, in which an E. tobaicum conidial suspension was applied to standardized needle wounds, the highest mean proportion of necrotic leaflet area was 26.17 ± 8.93% at 7 days after inoculation. Following artificial seed inoculation with E. tobaicum isolate 152H, no normal seedlings developed, and visible signs of fungal colonization were recorded on 100% of the seeds, indicating substantial adverse effects on seedling development under the experimental conditions. For 14 of the 15 isolates, 50% inhibition of mycelial growth by azoxystrobin was not reached at the highest tested concentration (EC₅₀ > 1000 µg/mL), indicating low sensitivity under the test conditions, whereas EC₅₀ values ranged from 0.0448 to 0.3837 µg/mL for boscalid, from 0.0760 to 0.2736 µg/mL for fludioxonil, and from 3.735 to 49.542 µg/mL for tebuconazole. These findings demonstrate substantial variation in fungicide sensitivity among the tested isolates, although further comparative studies are required to establish resistance status. To our knowledge, this study reports the first molecularly confirmed detection of E. tobaicum, E. mezzettii, and E. oryzae associated with soybean in Russia, as well as the first experimental evidence of the pathogenic potential of E. tobaicum toward soybean leaves in the country under controlled inoculation conditions. Because the conidial assay was performed on wounded leaflets, it does not establish the ability of these isolates to infect intact leaves under natural conditions.