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.

The manuscript discusses non-standard scientific and technological solutions for environmental monitoring, neutralization and subsequent deep processing of industrial and municipal waste. The manuscript is divided into three major sections devoted to monitoring, detoxification and processing of environmental pollutants. The following non-standard technological solutions for environmental monitoring are considered: Laser express chemical analysis; Laser remote sensing; Chemoresistive gas sensors for monitoring atmospheric conditions; Multi-beam optical analyzer for detection of microorganisms and organic pollutants. For neutralization of environmental pollutants, the following are considered: Modern catalysts for air purification from nitrogen and sulfur oxides; Adsorbents for carbon dioxide absorption; Advanced oxidation processes for purification of airport stormwater runoff; Advanced low-temperature plasma technologies; Catalysts for combustion of sewage sludge from municipal treatment facilities; Modern composite multifunctional polymer materials. Among technological solutions for deep processing of industrial and municipal waste, the following are considered: Nickel pincer complexes as electrocatalysts for molecular hydrogen evolution; Hydrogen sulfide-methane reforming for molecular hydrogen production; Technology of catalytic conversion of lignin-containing waste into adsorbents and fuel; New bacterial consortia for sewage sludge processing.

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.

The studies were conducted to create new consortia of microorganisms obtained from wild plant species (hypericum, oregano, plantain and reed) and to test their ability to be maintained in the soil and rhizosphere. The properties of 216 bacterial isolates that are important for protecting and stimulating plant growth, both in laboratory and field conditions, were determined, namely, enzymatic activity, including phytase, protease, lipase, nitrogenase, cellulase and amylase. In addition, the antagonistic activity of the isolates to the phytopathogenic fungus Fusarium oxysporum was tested. Then isolates were identified by comparing the 16S rRNA gene sequences. Pathogenic bacteria were then screened out and the most promising bacterial isolates were selected based on their enzymatic activities, from which a consortium was assembled to test the possibility of its maintenance in the soil and rhizosphere of Universiade wheat plants. For this purpose, the seeds were treated with the consortium at a dose of ×107 CFU/ml in a 1% carboxymethylcellulose solution and the soil and roots of the control and test plants were washed after 14 days. The presence or absence of the strains under study was determined by polymerase chain reaction fingerprinting. The consortium of microorganisms was better preserved in the soil than on the roots of plants. Its use increased the shoot length of experimental plants, relative to the control, by 38.6% (from 10.6 cm to 14.7 cm), the length of the root system by 22.1% (from 12.2 cm to 14.9 cm) and seed germination by 3.0% (from 87% to 90%). The obtained data can be used for further experiments and practical application in agriculture.

Multi-strain consortia are expected to protect plants more reliably than single strains, yet this is rarely tested directly, and the behavior of introduced strains in the field is difficult to follow. We assembled a consortium of Stenotrophomonas rhizophila MGMM118, Bacillus halotolerans MGMM119, Pseudomonas grimontii MGMM120 and Pseudomonas viciae MGMM121 strains isolated from the winter wheat rhizosphere and characterized their hydrolytic activities, auxin production, and analyzed their genomes. The consortium increased shoot and root length of wheat. In biocontrol experiments on barley, the consortium reduced the root rot disease index caused by Fusarium culmorum by approximately ten-fold (5.6% vs. 59.7%), outperforming each individual strain (11.9–17.9%). The consortium also reduced Fusarium root rot in tomato by two-fold. In a field experiment on wheat, strain-specific qPCR detected all introduced microorganisms in the wheat rhizosphere at up to 106 CFU per gram of soil, demonstrating different dynamics for each individual strain. Metabarcoding showed that community structure depended on plant developmental stage rather than on the consortium application. Since metabarcoding could not reliably identify the introduced strains, we suppose that strain-specific qPCR is a more appropriate tool for monitoring of inoculants, particularly in complex soil microbial communities.

Microorganisms are fundamental drivers of soil productivity, mediating nutrient cycling and pathogen suppression. In this study, we evaluated changes in the fungal community in the soil of barley (Hordeum vulgare L.) in a field experiment involving the application of a consortium of Paenibacillus pabuli, Priestia megaterium, Pseudomonas koreensis, and Pseudomonas orientalis. Seed pretreatment and seed pretreatment followed by rhizosphere drenching at different growth stages were implemented. Regarding fungal communities in bulk soil, the rhizospheres of untreated and treated plants were characterized based on full-length ribosomal RNA gene (18S-5.8S-28S) metabarcoding sequencing. Despite the compositional shifts, no statistical differences were observed among the alpha diversity metrics. Seed treatment resulted in long-term, targeted suppression of Fusarium graminearum, Fusarium fujikuroi, Fusarium musae, and Fusarium verticillioides from the booting through flowering and dough development stages, outperforming seed pretreatment followed by rhizosphere drenching. A low-modularity network was observed in the rhizosphere of untreated plants. Seed treatment fostered a highly interconnected and uniform network with low hub-betweenness scores. Rhizosphere drenching of pretreated seeds shifted the network topology toward higher hub-betweenness scores, reducing their connectivity by up to 10% in the rhizosphere and bulk soil. These findings provide a framework for optimizing the soil ecosystem for sustainable agriculture.