Saji George

Drought is a major constraint to crop productivity, highlighting the need for sustainable approaches to improve plant resilience. In this study, three endophytic bacteria, Bacillus subtilis BS-114 and BS-116, and Pseudomonas wadenswilerensis PPW-26, previously selected based on their plant growth-promoting traits and genomic potential, were evaluated for their ability to enhance drought resilience in common bean and tomato. Their effects were investigated through in vitro screening under polyethylene glycol (PEG)-induced drought, greenhouse drought validation, and open-field evaluation. Bacterial inoculation improved seed germination, seedling vigor, and plant water status under PEG-induced stress, with strain-dependent responses observed between crops, with the most pronounced effects observed in bean. Under greenhouse drought, inoculated bean plants exhibited improved photosynthetic performance and relative water content, together with reduced oxidative damage and proline accumulation, suggesting enhanced physiological adjustment to water deficit. These responses were associated with changes in the expression of drought-responsive genes involved in abscisic acid signaling, antioxidant defense, and osmoprotection, and were accompanied by a 52% increase in yield compared with non-inoculated drought-stressed plants. Based on greenhouse performance, a consortium containing BS-114 and two additional Bacillus strains was further evaluated under field conditions, where crop productivity was comparable to conventional NPK fertilization and a commercial algae-based biostimulant. Overall, these findings highlight the potential of beneficial endophytic bacteria isolated from medicinal plants to improve drought resilience, accompanied by changes in plant water status, hormonal signaling, and oxidative stress responses.

Bacterial endophytes are increasingly recognized for their ability to enhance plant growth and productivity through multiple physiological and biochemical mechanisms. However, how these responses are coordinated across plant developmental stages and translate into final crop performance remains unclear. This study evaluated previously characterized bacterial endophytes belonging to Bacillus subtilis (BS-114, BS-120) and Pseudomonas wadenswilerensis (PPW-26) as plant growth-promoting agents in yellow bean under in vitro , greenhouse, and field conditions. Bacterial treatments enhanced early developmental responses relative to the non-inoculated control (NC), with BS-114 increasing germination (+19.1%) and seedling total root length (+71.3%), while PPW-26 increased root biomass (+61.7%). Under greenhouse conditions, BS-114 improved reproductive development, increasing bud count (+47.4%), immature pod count (+60.2%), and pod fresh mass (+42.1%). Cell-free extracts reproduced several of these beneficial effects, with the BS-114 cell-free extract (BS-114E) producing the highest cumulative pod fresh mass (+94.2%), suggesting the contribution of extracellular components to reproductive performance. Physiological and gene-expression analyses further indicated that treatment responses were not attributable to a single pathway. Among the measured gas-exchange parameters, photosynthetic rate increased (+175.8%) and stomatal conductance increased (+306.9%). Gene expression analyses showed treatment-specific upregulation of selected genes, with N-fixation-related expression ( nifH ) reaching +5.62 log ₂ FC (49.31×) with the BS-114 live-cell treatment (BS-114L), while hormone-related responses were characterized by coordinated upregulation of auxin signaling-related expression +5.24 log ₂ FC (37.89×) and cytokinin-related expression patterns consistent with increased biosynthesis and reduced degradation. Field validation showed that all treatments increased yield relative to NC, with the BS-114+BS-120 consortium achieving a +32.65% increase, which was comparable to NPK (+37.76%), despite limited shifts in soil microbial diversity and moderate variation in soil nutrients. Together, these findings indicate that the evaluated bacterial treatments improved plant performance through coordinated responses across multiple biological levels and plant developmental stages, supporting their application as plant growth-promoting agents under controlled and field conditions.

Draft genome sequences of seven Bacillus strains isolated from Chelidonium majus seeds and six Pseudomonas strains isolated from Cannabis sativa roots and stems are reported. These genome sequences provide a foundation for functional and comparative genomic analyses to unravel potential traits associated with plant growth promotion and protection.

Endophytic bacteria contribute to plant growth, stress tolerance, and pathogen resistance. Their effective use in agriculture requires the identification of strains that combine multiple beneficial traits with consistent performance across different field conditions. Accordingly, this study examines Bacillus and Pseudomonas endophytes isolated from Cannabis sativa L. and Chelidonium majus L. for plant growth promotion, abiotic stress tolerance, and biocontrol properties. Plant growth-promotion traits included indole, siderophore, and organic acid production, phosphate and zinc solubilization, and biofilm formation. Results showed that all the tested bacterial isolates produced indoles, with the highest levels recorded in Pseudomonas strain PPW-26, whereas several Pseudomonas strains exhibited strong siderophore production. Strain PPW-26 tested positive for methyl-red, indicating organic acid production, whereas other Pseudomonas strains tested negative. Moderate to high nutrient solubilization profiles were observed across all Pseudomonas strains. Bacillus strains, particularly BS-114, exhibited higher biofilm formation relative to Pseudomonas . Assessment of abiotic stress tolerance included proline accumulation, superoxide dismutase activity, and growth under varying temperature, salinity, and drought conditions. All strains displayed tolerance to the tested stresses, with Bacillus strains showing stronger resilience to high temperature and salinity, accompanied by elevated proline accumulation and superoxide dismutase activity in selected strains. Biocontrol potential was evaluated through biosurfactant production and antifungal activity. Bacillus strains showed high biosurfactant activity and strong inhibition of fungal pathogens. Strain BS-120 exhibited broad-spectrum inhibition against Fusarium oxysporum , Fusarium graminearum , and Rhizoctonia solani -AG3. Analysis of genome sequences identified biosynthetic gene clusters encoding antifungal metabolites, including fengycin and surfactin, consistent with the observed inhibition. Genome-wide similarity analysis and ANI-based clustering revealed the presence of highly similar and genetically distant strains within each genus. For Bacillus spp., ANI values ranged from 87.62% to 98.83%, whereas for Pseudomonas spp. they ranged between 83.91% and 99.99%, confirming the presence of substantial intra-genus diversity. Phylogenetic analysis showed well-supported clades consistent with ANI clustering. Overall, this study demonstrates that endophytic Bacillus and Pseudomonas strains exhibit complementary and strain-dependent traits associated with plant growth promotion, stress tolerance, and pathogen suppression, supporting their further evaluation as potential bioinoculants for sustainable agriculture.

Multidrug-resistant (MDR) Salmonella enterica serovar Typhimurium (S. Typhimurium) poses a growing threat to food safety and animal health, particularly in the swine industry. In this study, we characterized a highly resistant ST strain isolated from a Quebec swine farm using whole-genome sequencing and phenotypic assays. The isolate harbored two plasmids, one of which encoded resistance to seven major antibiotic classes, including β-lactams, aminoglycosides, and sulfonamides, along with multiple virulence factors. To counteract these resistance mechanisms, we developed a nano-enabled antibacterial combination therapy (NeACT) by co-encapsulating amoxicillin (AMOX) and the β-lactamase inhibitor tazobactam into cyclodextrin encapsulated in liposomes (LP-CAT). Physicochemical analysis confirmed optimal particle size, charge, and stability, while checkerboard assays demonstrated strong drug synergism. The LP-CAT formulation drastically restored antimicrobial efficacy, reducing the AMOX minimum inhibitory concentration (MIC) from >2000 µg/mL to ~60 µg/mL. Using porcine intestinal epithelial (IPEC-J2) cells as an intracellular infection model, our study showed the potential of LP-CAT to remove >94% of intracellular bacteria with no cytotoxic effect. The ability of LP-CAT to resolve intestinal infection was further verified in Caenorhabditis elegans (C. elegans) intestinal infection model. These findings establish LP-CAT as a safe and effective strategy to revive antibiotic potency against intracellular MDR pathogens, offering a novel tool for combating antimicrobial resistance in livestock and safeguarding public health.

Agricultural intensification, to meet the nutritional needs of the growing world population, has been made possible through the extensive use of agrochemicals, such as synthetic fertilizers and pesticides. However, these practices pose significant health and environmental risks, including groundwater contamination, soil degradation and microbial resistance. Also, predictions indicate that relying solely on synthetic chemicals to boost production may not be enough to meet the future global need for food. Sustainable agricultural intensification involves the use of novel tools to enhance production while addressing environmental concerns using eco-friendly strategies, such as microbial inoculants. These can improve soil fertility, nutrient cycling and crop yield, while enhancing stress tolerance and overall crop fitness. This review outlines the key aspects of the global presence of plant diseases, plant defense responses and disease management strategies, and examines bacterial endophytes as crop biostimulants and biocontrol agents for sustainable control of mycotoxigenic fungi. It also proposes strategies to increase microbial product adoption by addressing technical limitations, such as field stability, delivery precision and shelf-life.

Bovine mastitis (BM), resulting from intramammary infection, is one of the costliest diseases in animal agriculture. Nano-enabled Antibacterial Combination Therapy (NeACT) holds promise for BM treatment.

Contemporary research in food packaging is focused on developing sustainable alternatives to petroleum‐based materials. Pullulan, a microbial biopolymer traditionally employed as a food additive, is harnessing interest for food packaging applications due to its exceptional film‐forming ability, biodegradability, and nontoxic nature. However, there are key limitations associated with the cost of production and suboptimal physicochemical attributes (e.g., inadequate water barrier and mechanical strength) that curtail the successful industrial translation of pullulan as a packaging polymer. Accordingly, this review examines effective ways for boosting biosynthetic efficiency of pullulan production through genetic and metabolic engineering of native strains and identifies emerging strategies such as targeted chemical modifications, electrospinning, incorporation of bioactive compounds, and film casting to enhance properties of pullulan‐based packaging materials. Encapsulation strategies for bioactive substances are emphasized in pullulan‐based active packaging for controlled release and sustained efficacy, whereas integration with pH‐responsive sensing entities enables smart packaging for real‐time freshness monitoring of protein‐rich foods. Further, we examined regulatory and safety frameworks, providing a perspective that bridges innovation with compliance requirements for commercial deployment. All in all, this review demonstrates the potential to reduce production costs and improve film properties, which has significantly strengthened the prospects of pullulan as a sustainable, biopolymer‐based alternative to synthetic materials.