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Drought stress is a major constraint on global agriculture, exacerbated by climatechange and increasing water scarcity. Conventional strategies such as breedingand genetic engineering have improved drought tolerance in crops, yet theirscalability and adaptability remain limited. Microbial interventions, particularlythose involving beneficial plant-associated microorganisms, offer a sustainableand complementary approach to enhance plant resilience under water-deficitconditions. This opinion article explores microbial strategies for droughtmitigation, emphasizing the role of Rhizobium strains, digested distillery spentwash, and multi-omics technologies. Recent studies demonstrate thatdeveloped Rhizobium strains significantly improve soil fertility, nodulation, andnitrogen fixation in legumes, contributing to higher yields and better soil health indrought-prone regions. Similarly, the application of digested distillery spent washin chickpea (Cicer arietinum) enhances nutrient uptake, photosynthetic activity,and drought tolerance. Advances in genomics, transcriptomics, proteomics, andmetabolomics have revealed complex plant–microbe interactions, identifyingmicrobial metabolites and signaling pathways that activate drought-responsivegenes and osmo-protective mechanisms. Despite these promising findings,challenges persist in translating laboratory results to field conditions due to soilheterogeneity and microbial competition. Precision microbiome engineering,informed by multi-omics data, and the development of tailored microbialconsortia represent a transformative frontier for sustainable agriculture. Byintegrating ecological complexity with technological innovation, microbialstrategies can reduce chemical inputs, promote regenerative practices, andbuild resilient agroecosystems. This article advocates elevating microbes fromsupporting roles to central players in addressing drought stress and ensuringglobal food security.

Nanoformulations deliver antibacterial agents synergistically. Positively charged Zn nanocomplexes were used as carriersfor chlorhexidine (CHX), developed using ionic liquids. The CHX-loaded Zn nanoparticles (CHZNPs) were characterisedthrough various techniques, including UV–visible Spectroscopy, TEM, FTIR, and Zeta potential analysis. The averagediameters of ZNPs and CHZNPs were 27.43 and 29.66 nm, respectively. CHZNPs consistently released CHX, enhancingits antibacterial effect. Tests against antibiotic-resistant Streptococcus pneumoniae strain 7465 revealed that CHZNPs significantlyreduced bacterial viability. At 100 μg/mL, CHX showed the highest antibacterial activity with the lowest minimalinhibitory concentration (MIC90) and minimal bactericidal concentration (MBC96) values, followed by CHZNPs, which hadlower MIC and MBC values. While ZNPs demonstrated some bactericidal effect at intermediate dosages (12 and 25 μg/mL), they could not fully inhibit bacterial growth. CHZNPs outperformed ZNPs across all concentrations, with an MIC of40 μg/mL compared to CHX’s 80 μg/mL. ZNPs showed no MIC at tested concentrations. Overall, CHZNPs significantlyreduced bacterial viability more effectively than CHX alone, highlighting their potential as a treatment for antibiotic-resistantS. pneumoniae infections.

Yersinia pathogenicity is dependent on polarized translocation of effectorproteins via the type III secretion system (T3SS). The tip complex situatedon the needle structure of the T3SS is required for contact with the eukaryotichost membrane and is to an extent composed of pentameric LcrV. LcrVis a multifunctional protein that also acts as a regulator of the T3SS by virtueof forming a high-affinity complex in the cytoplasm with its chaperone, LcrG.By employing a structure-based approach centered on mass spectrometry,FRET and NMR spectroscopy, we demonstrated that the LcrV-LcrG complexis best described as a multivalent complex, and that the N-terminaldomain of LcrV contributes by negatively affecting the LcrG binding affinity.The N-terminal domain of LcrV is dynamic and undergoes a conformationalchange to accommodate LcrG binding. 19F NMR spectroscopy analysissuggests that the conformational change is an intrinsic property of the protein,which agrees with a conformational selection model. An analysis ofeffector secretion into a culture supernatant demonstrated that the low synthesisand low secretion phenotypes of a LcrV mutant where the N-terminaldomain has been removed are linked to the structure, interactions and stabilityof the LcrV N-terminal domain. In summary, our results add insightsinto the dynamics of LcrV and its complex with LcrG.

Antibiotic resistance is a global healthcare crisis. Bacteria are highly adaptable and can rapidly acquiremechanisms of resistance towards conventional antibiotics. The permeability barrier conferred by theGram-negative bacteria cell envelope constitutes a first line of defence against the action ofantibiotics. Exposure to extracytoplasmic stresses can negatively affect cell envelope homoeostasisand this causes localised protein misfolding, compromised envelope integrity and impairs barrierfunction. The CpxA-CpxR two-component regulatory system has evolved to sense extracytoplasmicstresses and to regulate processes that restore homoeostasis of the cell envelope. Hence, controlledCpx-signalling assists bacteria in adapting, surviving and proliferating in harsh environments,including exposure to antibiotics. Herein, we determined that an intact Cpx-signalling is key tomaintaining the Yersinia pseudotuberculosis resistance to colistin and polymyxin B. The susceptibilitydisplayed by Cpx-signalling defective mutants, correlated with cell-envelope deformity and specificmodifications of Lipid-A. In vivo transcriptional analysis and in vitro protein-DNA binding studiesdemonstrated that these modifications were dependent on the direct regulation of Lipid-A biogenesisand modifications of operons by the active phosphorylated CpxR~P isoform. Altogether, our workdefines the regulatory mechanism that enables Cpx-signalling to actively control cell enveloperemodelling and the permeability of antibiotics in the clinically relevant enteropathogen Y.pseudotuberculosis.

Three strains of Gram‐negative bacterium, Rhizobium, were developed by gamma (γ)‐irradiation random mutagenesis. The developed strains were evaluated for their augmented features for symbiotic association, nitrogen fixation, and crop yield ofthree leguminous plants—chickpea, field‐pea, and lentil—in agricultural fields of the northern Indian state of Haryana. Crops treated with developed mutants exhibited significant improvement in plant features and the yield of crops when compared tothe control‐uninoculated crops and crops grown with indigenous or commercial crop‐specific strains of Rhizobium. This improvement was attributed to generated mutants, MbPrRz1 (on chickpea), MbPrRz2 (on lentil), and MbPrRz3 (on field‐pea). Additionally, the cocultured symbiotic response of MbPrRz1 and MbPrRz2 mutants was found to be more pronounced on allthree crops. The statistical analysis using Pearson's correlation coefficients revealed that nodulation and plant biomass were the most related parameters of crop yield. Among the effectiveness of developed mutants, MbPrRz1 yielded the best results for allthree tested crops. Moreover, the developed mutants enhanced macro‐ and micronutrients of the experimental fields whencompared with fields harboring the indigenous rhizobial community. These developed mutants were further genetically characterized, predominantly expressing nitrogen fixation marker, nifH, and appeared to belong to Mesorhizobium ciceri (MbPrRz1) and Rhizobium leguminosarum (both MbPrRz2 and MbPrRz3). In summary, this study highlights the potential ofdeveloped Rhizobium mutants as effective biofertilizers for sustainable agriculture, showcasing their ability to enhancesymbiotic relationships, crop yield, and soil fertility.

CTX-Ms are encoded by bla_CTX-M genes and are widely distributed extended-spectrum β-lactamases (ESBLs). They are the most important antimicrobial resistance (AMR) mechanism to β-lactam antibiotics in the Enterobacteriaceae. However, the role of transmissible AMR plasmids in the dissemination of bla_CTX-M genes has scarcely been studied in Africa where the burden of AMR is high and rapidly spreading. In this study, AMR plasmid transmissibility, replicon types and addiction systems were analysed in CTX-M-producing Escherichia coli clinical isolates in Ethiopia with a goal to provide molecular insight into mechanisms underlying such high prevalence and rapid dissemination. Of 100 CTX-Ms-producing isolates obtained from urine (84), pus (10) and blood (6) from four geographically distinct healthcare settings, 75% carried transmissible plasmids encoding for CTX-Ms, with CTX-M-15 being predominant (n = 51). Single IncF plasmids with the combination of F-FIA-FIB (n = 17) carried the bulk of bla_CTX-M-15 genes. In addition, IncF plasmids were associated with multiple addiction systems, ISEcp1 and various resistance phenotypes for non-cephalosporin antibiotics. Moreover, IncF plasmid carriage is associated with the international pandemic E. coli ST131 lineage. Furthermore, several CTX-M encoding plasmids were associated with serum survival of the strains, but less so with biofilm formation. Hence, both horizontal gene transfer and clonal expansion may contribute to the rapid and widespread distribution of bla_CTX-M genes among E. coli populations in Ethiopian clinical settings. This information is relevant for local epidemiology and surveillance, but also for global understanding of the successful dissemination of AMR gene carrying plasmids.

Bacteria express different types of hair-like proteinaceous appendages on their cell surface known as pili or fimbriae. These filamentous structures are primarily involved in the adherence of bacteria to both abiotic and biotic surfaces for biofilm formation and/or virulence of non-pathogenic and pathogenic bacteria. In pathogenic bacteria, especially Gram-negative bacteria, fimbriae play a key role in bacteria–host interactions which are critical for bacterial invasion and infection. Fimbriae assembled by the Chaperone Usher pathway (CUP) are widespread within the Enterobacteriaceae, and their expression is tightly regulated by specific environmental stimuli. Genes essential for expression of CUP fimbriae are organised in small blocks/clusters, which are often located in proximity to other virulence genes on a pathogenicity island. Since these surface appendages play a crucial role in bacterial virulence, they have potential to be harnessed in vaccine development. This review covers the regulation of expression of CUP-assembled fimbriae in Gram-negative bacteria and uses selected examples to demonstrate both dedicated and global regulatory mechanisms.

Plants do not grow in isolation; they interact with diverse microorganisms in their habitat.The development of techniques to identify and quantify the microbial diversity associated with plantscontributes to our understanding of the complexity of environmental influences to which plants areexposed. Identifying interactions which are beneficial to plants can enable us to promote healthygrowth with the minimal application of agrochemicals. Beneficial plant–microbial interactionsassist plants in acquiring inaccessible nutrients to promote plant growth and help them to copewith various stresses and pathogens. An increased knowledge of plant–microbial diversity can beapplied to meet the growing demand for biofertilizers for use in organic agriculture. This reviewhighlights the beneficial effects of soil–microbiota and biofertilizers on improving plant health andcrop yields. We propose that a multi–omics approach is appropriate to evaluate viability in thecontext of sustainable agriculture.

Conjugation is used by bacteria to propagate antimicrobial resistance (AMR) in the environment. Central to this process are widespread conjugative F-pili that establish the connection between donor and recipient cells, thereby facilitating the spread of IncF plasmids among enteropathogenic bacteria. Here, we show that the F-pilus is highly flexible but robust at the same time, properties that increase its resistance to thermochemical and mechanical stresses. By a combination of biophysical and molecular dynamics methods, we establish that the presence of phosphatidylglycerol molecules in the F-pilus contributes to the structural stability of the polymer. Moreover, this structural stability is important for successful delivery of DNA during conjugation and facilitates rapid formation of biofilms in harsh environmental conditions. Thus, our work highlights the importance of F-pilus structural adaptations for the efficient spread of AMR genes in a bacterial population and for the formation of biofilms that protect against the action of antibiotics.

Bacteria often reside in sessile communities called biofilms, where they adhere to a variety of surfaces and exist as aggregates in aviscous polymeric matrix. Biofilms are resistant to antimicrobial treatments, and are a major contributor to the persistence and chronicity of many bacterial infections. Herein, we determined that the CpxA-CpxR two-component system influenced the ability of enteropathogenic Yersinia pseudotuberculosis to develop biofilms. Mutant bacteria that accumulated the active CpxR~P isoform failed to form biofilms on plastic or on the surface of the Caenorhabditis elegans nematode. A failure to form biofilms on the worm surface prompted their survival when grown on the lawns of Y. pseudotuberculosis. Exopolysaccharide production by the hms loci is the major driver of biofilms formed by Yersinia. We used a number of molecular genetic approaches to demonstrate that active CpxR~P binds directly to the promoter regulatory elements of the hms loci to activate the repressors of hms expression and to repress the activators of hms expression. Consequently, active Cpx-signalling culminated in a loss of exopolysaccharide production. Hence, the development of Y. pseudotuberculosis biofilms on multiple surfaces is controlled by the Cpx-signalling, and at least inpart this occurs through repressive effects on the Hms-dependent exopolysaccharide production.