Browsing by Author "Stasiuk, Robert"

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    Bacterial osmoprotectants - a way to survive in saline conditions and potential crop allies
    (Oxford Academic, 2025-05-16) Goszcz, Aleksandra; Furtak, Karolina; Stasiuk, Robert; Wójtowicz, Joanna; Musiałowski, Marcin; Schiavon, Michela; Dębiec-Andrzejewska, Klaudia
    Soil salinization, affecting 6.5% of arable land, deteriorates soil properties, reduces microbiota activity, hinders plant growth, and accelerates soil erosion. Excessive salt induces physiological drought and toxicity stress in plants, causing chlorosis, ion imbalances, and enzyme disruptions. This paper discusses microorganisms’ resistance mechanisms, plant responses to salt stress and summarizes current knowledge on bacterial osmoprotectants and their functions. It also reviews emerging agrobiotechnological strategies using microbial osmoprotectants to remediate salinized soils and enhance plant growth and productivity under salt stress. Osmoprotectants stabilize proteins, buffer redox potential, and retain water, thus alleviating osmotic stress and promoting bacteria and plants growth. Their application improves soil properties by enhancing aggregate formation, water permeability, moisture content, cation exchange capacity, and ion availability. Despite extensive literature on the function of osmoprotectants, the knowledge about their role in soil environments and agrobiotechnology applications remains limited. This paper indicates proposed research perspectives, including discovering new osmoprotectants, their correlation with soil fertilization, interactions with the soil microbiome, and plant responses. It also identifies significant knowledge gaps in these areas, highlighting the need for further studies to consolidate existing data and assess the potential of this approach to enhance soil health and crop productivity in saline environments.
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    Salinity-driven evolution of psychrotolerant Bacillus velezensis S_51 strain reveals metabolic adaptations to osmotic stress and enhanced glycine betaine production
    (Springer Nature, BioMed Central (BMC), 2026) Goszcz, Aleksandra; Musiałowski, Marcin; Ciuchciński, Karol; Stasiuk, Robert; Błaziak, Kacper; Furtak, Karolina; Junkier, Aleksandra; Bernatowicz, Anna; Schiavon, Michela; Dębiec-Andrzejewska, Klaudia
    Soil salinisation limits agricultural productivity by disrupting microbial homeostasis and plant–microbe interactions. Osmoprotectants, including glycine betaine, play a crucial role in protecting microbial cells against osmotic stress by stabilising cellular structures and maintaining osmotic balance. To optimise microbial production of glycine betaine, adaptive laboratory evolution (ALE) was applied to Bacillus velezensis S_51 under increasing sodium chloride (NaCl) concentrations, providing insight into the underlying metabolic and genomic adaptations. After 10 sequential passages (500 generations), the evolved strain exhibited an adaptive shift in growth preference towards higher salinity from 0% to 4% (0.68 M) NaCl, indicating niche specialisation. This adaptation was accompanied by a pronounced increase in osmoprotection, with intracellular glycine betaine levels rising by ~262-fold relative to the ancestral strain, reaching to 882.25 ± 68.58 µM g⁻¹ DM. Metabolic profiling revealed a non-uniform reorganisation of substrate utilisation, with differentiation between ancestral (P1) and evolved (P10) strains largely driven by a limited subset of compounds (~62% contribution of key substrates). The evolved strain showed a ~ 4–5-fold increase in the number of effectively utilised carbon (C) and nitrogen (N) sources, with selective enhancement of specific amino acids (e.g., L-serine, L-aspartic acid) and reduced utilisation of several carbohydrates and hexose phosphates, indicating redistribution of substrate utilisation profiles under osmotic constraints. Functional trait analysis showed increased biofilm formation and elevated indole-3-acetic acid (IAA) production (from 0.1 to 0.13 µg mL⁻¹), while siderophore production remained stable. Genomic analysis identified mutations in key regulatory genes, including kapB, spo0A, and comP, suggesting an association between phenotypic shifts and regulatory network reconfiguration. Together, these results demonstrate that ALE drives coordinated metabolic, physiological, and regulatory adaptation, enhancing microbial fitness under saline conditions and supporting its application in saline soil biotechnologies.