Plant pathogens present a major challenge to crop production, leading to decreased yield and quality during growth and storage. During long-term storage, healthy onions can develop diseases from latent pathogen infections. This poses a challenge for onion growers because infected bulbs without visible symptoms can lead to significant crop losses during the growing season. In this study, we aimed to isolate and identify Fusarium species from yellow onion bulbs (Allium cepa L.) that developed disease symptoms during storage. The aggressiveness of these strains against onion bulbs and seedlings was also evaluated. The isolated strains were further subjected to morphological and molecular differentiation. The results revealed that all 16 isolated strains belonged to the Fusarium complex species incarnatum-equiseti and Fusarium fujikuroi, namely, F. proliferatum (98%), F. oxysporum (1%), and Fusarium sp. (1%). Koch’s postulate analysis of isolated strains revealed varying aggressiveness on onion bulbs and plants depending on fungal species. Disease symptoms developed more slowly on plants than on onion bulb plants according to Koch’s postulates. Moreover, the results revealed that Fusarium strains that can infect onion plants were less pathogenic to onion bulbs and vice versa. In addition, three isolates were found to be non-pathogenic to onions. Furthermore, the in vitro control of Fusarium species through Bacillus velezensis KS04-AU and Streptomyces albidoflavus MGMM6 showed high potential for controlling the growth of these pathogenic fungi. These results may contribute to the development of environmentally friendly approaches for controlling onion spoilage caused by pathogens during storage.

Microbial biotechnology plays a crucial role in improving industrial processes, particularly in the production of compounds with diverse applications. In this study, we used bioinformatic approaches to analyze the genomic architecture of Streptomyces albidoflavus MGMM6 and identify genes involved in various metabolic pathways that have significant biotechnological potential. Genome mining revealed that MGMM6 consists of a linear chromosome of 6,932,303 bp, with a high G+C content of 73.5%, lacking any plasmid contigs. Among the annotated genes, several are predicted to encode enzymes such as dye peroxidase, aromatic ring-opening dioxygenase, multicopper oxidase, cytochrome P450 monooxygenase, and aromatic ring hydroxylating dioxygenases which are responsible for the biodegradation of numerous endogenous and xenobiotic pollutants. In addition, we identified genes associated with heavy metal resistance, such as arsenic, cadmium, mercury, chromium, tellurium, antimony, and bismuth, suggesting the potential of MGMM6 for environmental remediation purposes. The analysis of secondary metabolites revealed the presence of multiple biosynthesis gene clusters responsible for producing compounds with potent antimicrobial and metal-chelating activities. Furthermore, laboratory tests conducted under controlled conditions demonstrated the effectiveness of MGMM6 in inhibiting phytopathogenic microbes, decolorizing and degrading aromatic triphenylmethane dyes, particularly Blue Brilliant G250, from wastewater by up to 98 ± 0.15%. Overall, the results of our study highlight the promising biotechnological potential of S. albidoflavus MGMM6.

Lignin is a complex aromatic polymer that constitutes a major fraction of plant biomass and represents a valuable renewable carbon resource. Naturally decaying wood serves as an environmental reservoir of microorganisms capable of degrading lignin. In this study, we isolated and characterized sixteen bacterial strains from decaying Tilia cordata wood using an enrichment culture technique with lignin as the sole carbon source. Taxonomic identification via 16S rRNA gene sequencing revealed microbial diversity spanning the genera Bacillus, Pseudomonas, Stenotrophomonas, and several members of the Enterobacteriaceae family, including Raoultella terrigena isolates. Metagenomic sequencing of the wood substrate revealed an exceptionally rich and balanced bacterial community (Shannon index H′ = 5.07), dominated by Streptomyces, Bradyrhizobium, Bacillus, and Pseudomonas, likely reflecting a specialized consortium adapted to lignin rich late-stage decay. Functional phenotyping demonstrated that all isolates possess ligninolytic potential, evidenced by peroxidase/laccase-type activity through methylene blue decolorization. Dynamic Light Scattering (DLS) and HPLC analyses showed that some isolates, such as Raoultella terrigena MGMM806, effectively depolymerized lignosulfonate into low molecular weight fragments (1.23 nm), while others accumulated intermediate metabolites or completely mineralized the substrate. Growth profiling on monolignol substrates revealed a broad spectrum of catabolic specialization in lignin monomer degradation. The results demonstrate a complex system of metabolic partitioning within a natural bacterial consortium. This collection represents a foundational genetic resource for developing engineered biocatalysts and synthetic microbial communities aimed at the efficient conversion of lignin into valuable aromatic compounds.

Pseudomonas putida PCL1760 is a well-studied bacterium that can be used for a wide range of biotechnological applications. In our study we investigated the effect of deletion of the genes involved in alginate accumulation (algA), flagellar export (flhA), and pili formation pilQ on the behavior of the strain in bioreactors. We obtained the knockout mutant P. putida LN6160 with the deletion of these genes and showed that the absence of these genes reduces mobility and biofilm formation (40% lower after 72 h) in the mutant. At the same time, we noted the positive effect of these deletions on the growth of the mutant strain on rich medium (1.39 × 10¹⁰ CFU/mL in the mutant and 6.4 × 10⁹ CFU/mL in the wild type) and on mineral medium (6.11 × 10⁹ CFU/mL in the mutant and 1.36 × 10⁹ CFU/mL in the wild type) by growing them in small-volume bioreactors. A significant decrease in the biofilm and the foam formation was also observed for LN6160 in a small-volume bioreactor. Most probably, the rapid growth of the deletion strain occurs due to a decrease in the energy load on the bacterial apparatus.

Свободноживущая почвенная нематода Caenorhabditis elegans является удобным модельным организмом для изучения взаимодействий между бактериями и организмом хозяина благодаря своим уникальным характеристикам: короткому жизненному циклу, простоте культивирования и наличию консервативных иммунных путей, гомологичных таковым у млекопитающих. Исследования показали, что бактерии используют различные стратегии патогенности в отношении C. elegans, включая медленное убийство через колонизацию кишечника (например, Pseudomonas aeruginosa) и быстрое убийство за счет выделения токсинов (синильная кислота, гемолизины). Особый интерес представляют бактерии видов Salmonella typhimurium и Enterococcus faecalis, способные к длительной персистенции в кишечнике нематод. Генетические исследования выявили ключевые факторы вирулентности, такие как гены lasR и gacA у P. aeruginosa, а также роль секреторных систем III типа у S. typhimurium. При этом устойчивость C. elegans к патогенам связана с работой антиоксидантных систем и митохондриальным ответом. Нематода также служит эффективной моделью для скрининга потенциальных агентов биологической защиты растений, например, штаммов Bacillus thuringiensis, продуцирующих нематоцидные Cry-токсины. Важно отметить, что многие бактерии (P. aeruginosa, Burkholderia spp., Serratia marcescens) демонстрируют сходные механизмы патогенности у беспозвоночных и млекопитающих, что подчеркивает универсальность изученных процессов. Таким образом, C. elegans представляет собой мощный инструмент для исследования фундаментальных аспектов бактериальной вирулентности и иммунного ответа, что открывает новые перспективы для разработки стратегий борьбы с инфекциями и создания биопрепаратов для защиты растений

The selection of an optimal antifoam is critical for efficient fermentation, as industrial agents often have detrimental side effects like growth inhibition, while some can enhance productivity. We studied the efficacy of novel silicone–polyol antifoam emulsions for use in fermentation as defoamers. Except for agent 3L10, all antifoams tested did not show inhibition on six bacterial and one fungal culture. Interestingly, agent 3L10 strongly inhibited Gram-positive bacteria (especially Corynebacterium glutamicum) but not Gram-negative strains. A comprehensive evaluation protocol—combining chemical design, cytotoxicity screening across diverse microorganisms, the determination of minimum effective concentrations (MECs), and validation in model bioreactor fermentations—was established. Through this process, 6T80 was identified as a promising antifoam agent for fermentation. It exhibited a low MEC, high emulsion stability, and no cytotoxicity and did not impair growth or recombinant protein production in Bacillus subtilis or Pseudomonas putida fermentations. This study concludes that agent 6T80 is suitable for further application in processes involving Gram-negative and certain Gram-positive hosts. The developed methodology enables the targeted selection of highly efficient and biocompatible antifoams for specific biotechnological processes.