Effector proteins secreted by bacteria that infect mammalian and plant cells often subdue eukaryotic host cell defenses by simultaneously affecting multiple targets. However, instances when a bacterial effector injected in the competing bacteria sabotage more than a single target have not been reported. Here, we demonstrate that the effector protein, LtaE, translocated by the type IV secretion system (T4SS) from the soil bacterium Lysobacter enzymogenes into the competing bacterium, Pseudomonas protegens, affects several targets, thus disabling the antibacterial defenses of the competitor. One LtaE target is the transcription factor, LuxR1, that regulates biosynthesis of the antimicrobial compound, orfamide A. Another target is the sigma factor, PvdS, required for biosynthesis of another antimicrobial compound, pyoverdine. Deletion of the genes involved in orfamide A and pyoverdine biosynthesis disabled the antibacterial activity of P. protegens, whereas expression of LtaE in P. protegens resulted in the near-complete loss of the antibacterial activity against L. enzymogenes. Mechanistically, LtaE inhibits the assembly of the RNA polymerase complexes with each of these proteins. The ability of LtaE to bind to LuxR1 and PvdS homologs from several Pseudomonas species suggests that it can sabotage defenses of various competitors present in the soil or on plant matter. Our study thus reveals that the multi-target effectors have evolved to subdue cell defenses not only in eukaryotic hosts but also in bacterial competitors.

Growing numbers of infections caused by antibiotic-resistant Streptococcus pneumoniae strains are a major concern for healthcare systems that will require new antibiotics for treatment as well as preventative measures that reduce the number of infections. Lipopeptides are antimicrobial molecules, of which some are used as antibiotics, including the last resort antibiotics daptomycin and polymyxins. Here we have studied the antimicrobial effect of the cyclic lipopeptide viscosin on S. pneumoniae growth and morphology. Most lipopeptides function as surfactants that create pores in membrane layers, which is regarded as their main antimicrobial activity. We show that viscosin can inhibit growth of S. pneumoniae without disintegration of the cytoplasmic membrane. Instead, the cells developed abnormal shapes and misplaced new division sites. The cell wall of these bacteria appeared less dense in electron microscopy images, suggesting that viscosin interfered with normal cell wall synthesis. Corroborating this observation, a luciferase reporter assay was used to show that the two-component systems LiaFSR and CiaRH, which are known to be activated upon cell wall stress, were strongly induced by viscosin. Furthermore, a mutant displaying 1.8-fold decreased susceptibility to viscosin was generated by sequential exposure to increasing concentrations of the lipopeptide. The mutant suffered from significant fitness loss and had mutations in genes involved in fatty acid synthesis, teichoic acid synthesis, and cell wall synthesis as well as transcription and translation. How these mutations might be linked to decreased viscosin susceptibility is discussed.IMPORTANCEStreptococcus pneumoniae is a leading cause of bacterial pneumonia, sepsis, and meningitis in children, and the incidence of infections caused by antibiotic-resistant strains is increasing. Development of new antibiotics is therefore necessary to treat these types of infections in the future. Here, we have studied the activity of the antimicrobial lipopeptide viscosin on S. pneumoniae and show that in addition to having the typical membrane destabilizing activity of lipopeptides, viscosin inhibits pneumococcal growth by obstructing normal cell wall synthesis. This suggests a more specific mode of action than just the surfactant activity. Furthermore, we show that S. pneumoniae does not easily acquire resistance to viscosin, which makes it a promising molecule to explore further, for example, by synthesizing less toxic derivates that can be tested for therapeutic potential.

Contact lenses (CL) have become an immensely popular means of vision correction, offering comfort to millions worldwide. However, the persistent issue of biofilm formation on lenses raises significant problems, leading to various ocular complications and discomfort. The aim of this review is to develop safer and more effective strategies for preventing and managing microbial biofilms on CL, improving the eye health and comfort of wearers. Taking these into consideration, the present study investigates the intricate mechanisms of biofilm formation, by exploring the interplay between microbial adhesion, the production of extracellular polymeric substances, and the properties of the lens material itself. Moreover, it emphasizes the diverse range of microorganisms involved, encompassing bacteria, fungi, and other opportunistic pathogens, elucidating their implications within lenses and other medical device-related infections and inflammatory responses. Going beyond the challenges posed by biofilms on CL, this work explores the advancements in biofilm detection techniques and their clinical relevance. It discusses diagnostic tools like confocal microscopy, genetic assays, and emerging technologies, assessing their capacity to identify and quantify biofilm-related infections. Finally, the paper delves into contemporary strategies and innovative approaches for managing and preventing biofilms development on CL. In Conclusion, this review provides insights for eye care practitioners, lens manufacturers, and microbiology researchers. It highlights the intricate interactions between biofilms and CL, serving as a foundation for the development of effective preventive measures and innovative solutions to enhance CL safety, comfort, and overall ocular health. Research into microbial biofilms on CL is continuously evolving, with several future directions being explored to address challenges and improve eye health outcomes as far as CL wearers are concerned.

Improved and contemporary agriculture relies heavily on pesticides, yet some can be quite persistent and have a stable chemical composition, posing a significant threat to the ecology. Removing harmful effects is upon their degradability. Biodegradation must be emphasized to lower pesticide degradation costs, especially in the soil. Here, a decision-making system was used to determine the best microbial strain for the biodegradation of the pyrethroid-contaminated soil. In this system, the criteria chosen as: pH (C1), Temp (C2), RPM (C3), Conc. (C4), Degradation (%) (C5) and Time required for degradation(hrs) (C6); and five alternatives were Bacillus (A1), Acinetobacter (A2), Escherichia (A3), Pseudomonas (A4), and Fusarium (A5). The best alternative was selected by applying the TOPSIS (technique for order performance by similarity to ideal solution) method, which evaluates based on their closeness to the ideal solution and how well they meet specific requirements. Among all the specified criteria, Acinetobacter (A2) was the best and optimal based on the relative closeness value (( R i ∗ ) = 0.740 (A2) > 0.544 (A5) > 0.480 (A1) > 0.403 (A4) > 0.296 (A3)). However, the ranking of the other alternatives is also obtained in the order Fusarium (A5), Bacillus (A1), Pseudomonas (A4), Escherichia (A3). Hence this study suggests Acinetobacter is the best microbial strain for biodegradation of pyrethroids; while least preference should be given to Escherichia. Acinetobacter, versatile metabolic nature with various xenobiotic compounds\' degradation ability, is gram-negative, aerobic, coccobacilli, nonmotile, and nonspore forming bacteria. Due to less study about Acinetobacter it is not in that much frame as the other microorganisms. Hence, considering the Acinetobacter strain for the biodegradation study will give more optimal results than the other microbial strains. Novelty of this study, the TOPSIS method is applied first time in selecting the best microbial strain for the biodegradation of pyrethroid-contaminated soil, considering this selection process as multi-criteria decision-making (MCDM) problem.

A Gram-negative, strictly aerobic bacterial strain was isolated from asymptomatic leaf tissue of a wild yam plant. Optimal growth was observed at 28 °C and pH 7, and catalase and oxidase activities were detected. Polyphasic taxonomic and comparative genomics revealed that strain LMG 33091T represents a novel species of Pseudomonas. The nearest phylogenetic neighbours of strain LMG 33091T were Pseudomonas putida NBRC 14164T (with 99.79 % 16S rRNA sequence identity), Pseudomonas alkylphenolica KL28T (99.28 %) and Pseudomonas asplenii (99.07 %) ATCC 23835T. MALDI-TOF MS analysis yielded distinct profiles for strain LMG 33091T and the nearest phylogenetic neighbours. Average nucleotide identity analyses between the whole genome sequence of strain LMG 33091T and of the type strains of its nearest-neighbour taxa yielded values below the species delineation threshold and thus confirmed that the strain represented a novel Pseudomonas species, for which we propose the name Pseudomonas fortuita sp. nov., with strain LMG 33091T (=GMI12077T= CFBP 9143T) as the type strain.

Here, we report the draft genome sequence of endophytic Pseudomonas sp. 102515 isolated from Taxus chinensis collected from Logan, UT, USA. The genome is composed of 36 contigs and around 4.9 Mbp in size. The GC content is 66% with an N50 length of 918.9 kbp and L50 count of 2.

Phage therapy is increasing in relevance as an alternative treatment to combat antibiotic resistant bacteria. Phage cocktails are the state-of-the-art method of administering phages in clinical settings, preferred over monophage treatment because of their ability to eliminate multiple bacterial strains and reduce resistance formation. In our study, we compare monophage applications and phage cocktails to our chosen method of phage sequential treatments. To do so, we isolated four novel bacteriophages capable of infecting Pseudomonas alcaligenes T3, a close relative of P. aeruginosa, and characterized them using sequencing and transmission electron microscopy. While investigating monophage treatments, we observed that different phage concentrations had a strong impact on the timing and amount of resistance formation. When using phage cocktails, we observed that P. alcaligenes were capable of forming resistance in the same timespan it took them to become resistant to single phages. We isolated mutants resistant to each single phage as well as mutants exposed to phage cocktails, resulting in bacteria resistant to all four phages at once. Sequencing these mutants showed that different treatments yielded unique single nucleotide polymorphism mutation patterns. In order to combat resistance formation, we added phages one by one in intervals of 24 h, thus managing to delay resistance development and keeping bacterial growth significantly lower compared to phage cocktails.IMPORTANCEWHO declared antimicrobial resistance a top threat to global health; while antibiotics have stood at the forefront in the fight against bacterial infection, the increasing number of multidrug-resistant bacteria highlights a need to branch out in order to address the threat of antimicrobial resistance. Bacteriophages, viruses solely infecting bacteria, could present a solution due to their abundance, versatility, and adaptability. For this study, we isolated new phages infecting a fast-mutating Pseudomonas alcaligenes strain capable of forming resistance within 30 h. By using a sequential treatment approach of adding one phage after another, we were able to curb bacterial growth significantly more compared to state-of-the-art phage cocktails.

In this study, we focused on evaluating the impact of Pseudomonas abietaniphila BHJ04 on the growth of Pinus massoniana seedlings and its biocontrol efficacy against pine wilt disease (PWD). Additionally, the colonization dynamics of P. abietaniphila BHJ04 on P. massoniana were examined. The growth promotion experiment showed that P. abietaniphila BHJ04 significantly promoted the growth of the branches and roots of P. massoniana. Pot control experiments indicated that strain BHJ04 significantly inhibited the spread of PWD. There were significant changes in the expression of several genes related to pine wood nematode defense in P. massoniana, including chitinase, nicotinamide synthetase, and triangular tetrapeptide-like superfamily protein isoform 9. Furthermore, our results revealed significant upregulation of genes associated with the water stress response (dehydration-responsive proteins), genetic material replication (DNA/RNA polymerase superfamily proteins), cell wall hydrolase, and detoxification (cytochrome P450 and cytochrome P450 monooxygenase superfamily genes) in the self-regulation of P. massoniana. Colonization experiments demonstrated that strain BHJ04 can colonize the roots, shoots, and leaves of P. massoniana, and the colonization amount on the leaves was the greatest, reaching 160,000 on the 15th day. However, colonization of the stems lasted longer, with the highest level of colonization observed after 45 d. This study provides a preliminary exploration of the growth-promoting and disease-preventing mechanisms of P. abietaniphila BHJ04 and its ability to colonize pines, thus providing a new biocontrol microbial resource for the biological control of plant diseases.

An approach based on the heat stress and microbial stress model of the medicinal plant Sparganium stoloniferum was proposed to elucidate the regulation and mechanism of bioactive phenol accumulation. This method integrates LC-MS/MS analysis, 16S rRNA sequencing, RT-qPCR, and molecular assays to investigate the regulation of phenolic metabolite biosynthesis in S. stoloniferum rhizome (SL) under stress. Previous research has shown that the metabolites and genes involved in phenol biosynthesis correlate to the upregulation of genes involved in plant-pathogen interactions. High-temperature and the presence of Pseudomonas bacteria were observed alongside SL growth. Under conditions of heat stress or Pseudomonas bacteria stress, both the metabolites and genes involved in phenol biosynthesis were upregulated. The regulation of phenol content and phenol biosynthesis gene expression suggests that phenol-based chemical defense of SL is stimulated under stress. Furthermore, the rapid accumulation of phenolic substances relied on the consumption of amino acids. Three defensive proteins, namely Ss4CL, SsC4H, and SsF3\'5\'H, were identified and verified to elucidate phenol biosynthesis in SL. Overall, this study enhances our understanding of the phenol-based chemical defense of SL, indicating that bioactive phenol substances result from SL\'s responses to the environment and providing new insights for growing the high-phenol-content medicinal herb SL.

Photorespiratory serine hydroxymethyltransferases (SHMTs) are important enzymes of cellular one-carbon metabolism. In this study, we investigated the potential role of SHMT6 in Arabidopsis thaliana. We found that SHMT6 is localized in the nucleus and expressed in different tissues during development. Interestingly SHMT6 is inducible in response to avirulent, virulent Pseudomonas syringae and to Fusarium oxysporum infection. Overexpression of SHMT6 leads to larger flowers, siliques, seeds, roots, and consequently an enhanced overall biomass. This enhanced growth was accompanied by increased stomatal conductance and photosynthetic capacity as well as ATP, protein, and chlorophyll levels. By contrast, a shmt6 knockout mutant displayed reduced growth. When challenged with Pseudomonas syringae pv tomato (Pst) DC3000 expressing AvrRpm1, SHMT6 overexpression lines displayed a clear hypersensitive response which was characterized by enhanced electrolyte leakage and reduced bacterial growth. In response to virulent Pst DC3000, the shmt6 mutant developed severe disease symptoms and becomes very susceptible, whereas SHMT6 overexpression lines showed enhanced resistance with increased expression of defense pathway associated genes. In response to Fusarium oxysporum, overexpression lines showed a reduction in symptoms. Moreover, SHMT6 overexpression lead to enhanced production of ethylene and lignin, which are important components of the defense response. Collectively, our data revealed that SHMT6 plays an important role in development and defense against pathogens.