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Enzymatic and antioxidative responses are key defense mechanisms in plants following pathogen invasion, collectively known as induced systemic resistance (ISR). Alternaria sp., a well-known soil-borne pathogen, causes blight diseases in various crops. This study investigates the defence response in lentil plants through the treatment-induced application of two multipotent pesticide degrading plant growth-promoting rhizobacteria (PGPR), Bacillus cereus and Bacillus safensis, to mitigate the destructive effects of Alternaria. Both bacterial strains were applied in different carrier-based bioformulations via soil drenching. We assessed the modulation of defense-related enzymes by various combinational treatments with the Alternaria pathogen. The in vitro production of antimicrobial compounds was analyzed using GC-MS to confirm their pathogen-suppressive capabilities. Field trials showed a positive correlation between treatments and improvements in yield and growth index (GI). The highest (180%) enzymatic induction of phenylalanine ammonia lyase (PAL) followed by catalase (CAT)(100%) and polyphenol oxidase (PPO) (54%), was observed in treatments with B. cereus alone or in combination with B. safensis, in presence of Alternaria, in respect to the control. In vitro analysis revealed the production of antimicrobial compounds, including benzoic acid derivatives, cyclotetrasiloxanes, hexacosane, chlorpyrifos, and phthalates, which may contribute to pathogen suppression. Our findings demonstrate that these biocontrol agents (BCAs) not only stimulate the plant's enzymatic defense system but also enhance growth, seed yield and produce several antimicrobial compounds in vitro. Thus, pesticide-tolerant PGPR, used in this study, exhibit both disease control and plant growth-promoting properties, offering promising applications in sustainable agriculture., Competing Interests: Declarations. Conflict of interest: The authors have no relevant financial or non-financial interests to disclose., (© 2025. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Endophytic bacteria derived from metal hyperaccumulators have demonstrated potential for improving copper (Cu) remediation in host plants; however, their potential application in non-host crops remains unclear. In this study, endophytic bacteria isolated from Commelina communis growing in mining areas and their mitigation effects on Cu toxicity in non-host rice were comprehensively evaluated. Among the isolated endophytes, Bacillus sp. D2 exhibited the highest Cu resistance, producing indole-3-acetic acid (IAA) at a concentration of 0.93 mg/L and exhibiting ACC deaminase activity of 13.88 μmol/mg·h under 200 mg/L Cu stress. Pot-experiment results revealed that Bacillus sp. D2 addition significantly increased the biomass and lengths of shoots under Cu stress conditions by 47.6% and 14.2%, respectively. Furthermore, Bacillus sp. D2 inoculation significantly reduced oxidative damage, enhanced antioxidant responses, and modulated plant hormone levels in Cu-exposed rice. Notably, Bacillus sp. D2 inoculation substantially decreased the upward translocation of Cu from underground roots to aboveground tissues. Moreover, Bacillus sp. D2 effectively alleviated Cu toxicity in rice plants by regulating the expression levels of genes involved in antioxidant systems (tAPx, Csd2, and FeSOD1), Cu transporters (AtPDR8 and HMA3), as well as metallothionein (MT2c). These results highlight the value of Bacillus sp. D2 as a bioinoculant for improving crop growth while reducing the risks associated with copper contamination in naturally Cu-contaminated soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Deoxynivalenol (DON) contamination in cereals and their products poses a potential threat to animal and human health, however, physical and chemical detoxification methods deplete nutrients and cannot specifically remove DON. This study aims to identify novel and efficient DON-degrading enzymes, providing practical support for their application in biodegradation. A novel DON-degrading aldo-keto reductase named AKR11A2 was identified from Bacillus velezensis Vel-HNGD-F2 through BlastP comparison. AKR11A2, an enzyme with a molecular mass of 34.8 kDa encoded by a 933 bp gene, exhibited optimal activity at pH 9 and 40 °C, while demonstrating remarkable thermal and alkaline stability by retaining over 90% of its activity. UPLC-MS/MS analysis revealed that the m/z of the DON degradation product was 295.1, identified as 3-epi-DON, formed through the direct isomerization of DON. Notably, zebrafish experiments demonstrated that the liver toxicity of the degradation product was significantly lower than that of DON. AKR11A2 effectively degraded 50.69% of the DON in contaminated corn, highlighting its practical application in food safety. These findings indicate that the study achieved the biodegradation of DON and provide a promising theoretical and technological support for the application of DON detoxifying enzymes in food and feed products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The coexistence of antibiotics with heavy metals is detrimental to humans and the environment. In urban water environments, Cadmium (Cd) and ciprofloxacin (CIP) frequently co-occur. Biogenic manganese oxides (BMOs) are a promising environmental bioremediation material due to their remarkable adsorption and oxidation properties. However, BMOs' removal mechanism in an environment where Cd and CIP co-occur is not yet unknown. We identified a manganese (Mn)-oxidising bacterium, Bacillus sp. XM02, with a strong ability for Mn (II) oxidation (85.23%) and BMOs production, and investigated its competitive removal mechanism in an environment with Cd and CIP co-occurrence. The BMOs exhibited a glorious CIP degradation ability and led to a marked decrease in the toxicity of CIP following oxidative degradation in Escherichia coli experiments. In contrast, in the co-existence of Cd and CIP, Cd hindered CIP removal by BMOs, but CIP did not affect Cd removal. Kinetic experiments combined with XPS characterisation revealed that the k value of Cd (297.39 h -1 ) was much higher than that of CIP (5.53 h -1 ), demonstrating that Cd was immediately adsorbed onto the surface of BMOs through a Cd-O bond. The surface potentials of BMOs carrying Cd alone and both Cd and CIP on the surface were similar, revealing that the electronegativity of Cd-carrying BMOs was greatly weakened (from -34.8 mV to -21 mV/-23 mV), which further reduced the BMOs' electrostatic interaction with CIP. Moreover, the concentration of dissolved Mn (III) in the co-existence group was lower than that in the CIP alone, indicating that the presence of Cd reduced the transformation of Mn (IV) to Mn (III) by BMOs. Consequently, Cd attenuated the effect of active Mn (IV) sites of BMOs on CIP's piperazine ring oxidative degradation. These results offer a theoretical direction for the use of BMOs to reduce the risk posed by antibiotics and heavy metals pollution in co-occurrence environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Fusarium dry rot, Pythium leak and Southern blight diseases caused by various Fusarium species, Pythium aphanidermatum, and Agroathelia rolfsii, respectively, are responsible for important losses of tuber at the post-harvest stage in Tunisia. In the present study, six Bacillus strains, isolated from wild solanaceous plants, were screened for their abilities to inhibit potato pathogens in vitro and on potato tubers. Based on the dual culture assays, the whole cell suspensions of B. tequilensis SV39 and SV104, B. subtilis SV41, B. methylotrophicus SV44 and B. amyloliquefaciens subsp. plantarum SV65 exhibited potent antifungal activity against target pathogens. Significant inhibitory effects were also induced by their cell-free culture filtrates, butanolic and chloroform extracts depending on target pathogens, concentration used and bacterial strains tested. The gas chromatography-mass spectrometry (GC-MS) analysis of B. tequilensis SV39 butanolic extract revealed the highest relative abundance of phthalic acid and derivatives as major volatile compounds. The current study sheds light on the ability of all bacterial strains to reduce the lesion diameter or rot penetration by about 59-61 % and 51-58 %, respectively. Furthermore, B. tequilensis SV104 and SV39 were the most effective bio-agents in reducing the lesion diameter by 64.06 and 57.31 %, respectively, while SV104 (B. tequilensis), SV41 (B. subtilis) and SV65 (B. amyloliquefaciens subsp. plantarum) based treatments were the most effective in decreasing the rot penetration by 54-63 %. The application of these Bacillus strains constitutes a promising alternative for an efficient and safe control of potato storage diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Root exudates serve as chemical signaling molecules that regulate rhizosphere interactions and control soil-borne diseases. The interactions between plants and the soil microbiome play dynamic and crucial roles in regulating the resistance of plants to biotic stress. However, the specific roles of many root exudates in plant pathogens remain unclear. The root exudate methyl ferulate, a naturally occurring and relatively non-toxic antifungal agent, has been applied to control postharvest pathogens and preserve foodstuffs and has not been used in plant disease control., Results: This study investigated the role of the root exudate methyl ferulate in controlling tobacco black shank disease. We observed that methyl ferulate was secreted in greater quantities in the tobacco resistant cultivar Gexin 3 following inoculation with P. nicotianae than in the susceptible cultivar Xiaohuangjin 1025. Our findings also revealed that methyl ferulate strongly inhibited P. nicotianae (EC 50  = 67.51 µg/mL), effectively controlling tobacco black shank disease by impairing NADH dehydrogenase function (the activity decreased by 50%). Furthermore, methyl ferulate recruited disease-suppressive rhizosphere microbes, such as Bacillus (the relative abundance of these microbes increases from 4.69% to 13.79%), thereby increasing disease resistance. The overexpression of caffeic acid O-methyltransferase NtCOMT10 resulted in increased methyl ferulate secretion (increased to 221.09% compared with that of the wild-type), concomitant improvement in the disease suppression of tobacco black shank disease (disease index decreased from 20% to less than 10%) and enrichment of beneficial microbes. In addition, methyl ferulate exerted antagonistic effects on other phytopathogens, such as B. cinerea, P. aphanidermatum, P. sojae, C. lagenarium and F. oxysporum., Conclusions: Our findings indicated that methyl ferulate, a component of root exudates regulated by NtCOMT10, can inhibit phytopathogens and enrich rhizosphere Bacillus against plant disease. The great dual effect of methyl ferulate on the control of phytopathogens and its low cost enable a novel potential avenue for controlling soil-borne fungal diseases. This study provides ingenious insights into controlling soil-borne diseases through beneficial root exudates. Video Abstract., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

MWCNT is being explored in various sectors like medical healthcare, electronics, aerospace, defence research, and many more leading to the continuous generation of waste discharged into water sources. Once introduced into the environment it may adversely affect flora and fauna. It is high time MWCNT should be recovered, treated, and degraded from wastewater. Bio-degradation is one of the popular sustainable techniques for the remediation of hazardous contaminants. This work evaluated indigenous microbes Bacillus nitratireducens SW_NMI_TSB1, Comamonas denitrificans SW_NMI_TSB2, and Lysinibacillus fusiformis SW_NMI_TSB3 isolated from the nanomaterial manufacturing industry from India for their competence in degrading MWCNT. The microbes in this study showed survivability in the nutrient medium devoid of carbon but containing MWCNT (100 and 400 mg/L). The bacterial strain exhibited proliferation for up to 50 days. Degradation of MWCNT can be observed through TEM images which displayed the distorted morphology, XRD, and RAMAN spectroscopy revealed that treated MWCNT exhibit a loss of structural integrity. SEM images and colony forming unit (CFU) counts show a good survival rate of the three isolates independently and in the consortium. LCMS detected intermediates generated during MWCNT degradation. The microbes isolated in this study can survive in the presence of MWCNT and exhibit degradation of MWCNT. The three isolates could biodegrade the MWCNT however their consortium showed the highest potential. The prospects of this study lie in utilizing the consortium of these strains for large-scale MWCNT degradation, improving water treatment systems, and advancing sustainable nanomaterial management practices., Competing Interests: Declarations. Conflict of interest: The authors declare no conflict of interest. Ethical approval: In underlying research work no experiment/ issue necessitates ethical consent/ agreement., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Bacillus safensis APC 4099, isolated from bees' gut, has been identified as a promising candidate for food biopreservation. Antimicrobial activity screening revealed a broad-spectrum inhibition potential, ranging from gram-positive pathogenic bacteria to fungi responsible for food spoilage. Genomic analysis identified biosynthetic gene clusters coding for several antimicrobial peptides and secondary metabolites. Specifically, a novel, anionic, 6 kDa circular bacteriocin, named safencin E, was detected, showing 52.5% similarity to butyrivibriocin AR10. Additionally, gene clusters coding for the biosynthesis of bacteriocins such as pumilarin and plantazolicin and biosynthetic pathways for secondary metabolites, including pumilacidin A, bacilysin, and bacillibactin, were identified. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis detected molecular masses correlating to safencin E, plantazolicin, pumilarin, and pumilacidin A from the cell-free supernatant, cell extracts, or both. Overall, the broad-spectrum antimicrobial activity of B. safensis APC 4099 indicates that this strain is a promising candidate for the biological control of food ecosystems and thus has the potential to enhance food safety., Importance: The present article highlights the importance of the strain Bacillus safensis APC 4099 as a potential biocontrol agent. The strain possesses biosynthetic gene clusters coding for various antimicrobial peptides and secondary metabolites, including a novel circular bacteriocin, safencin E, and the bacteriocins pumilarin and plantazolicin. This diversity in the production of antimicrobial peptides renders the producer with broad-spectrum antimicrobial activity, ranging from gram-positive pathogenic and spoilage bacteria to spoilage molds. Considering that 1.3 billion tons of food appropriate for human consumption is lost or wasted annually, identifying strains or novel antimicrobial peptides capable of biopreservation is highly relevant. This strain and its bioactive compounds offer a solution to this global problem as biocontrol agents for food ecosystems against spoilage and pathogenic microbes., Competing Interests: The authors declare no conflict of interest.

Antibiotic secretion plays a pivotal role in bacterial interference competition; yet, the impact of environmental hydration conditions on such competition is not well understood. Here, we investigate how hydration conditions affect interference competition among bacteria, studying the interactions between the antibiotic-producing Bacillus velezensis FZB42 and two bacterial strains susceptible to its antibiotics: Xanthomonas euvesicatoria 85-10 and Pseudomonas syringae DC3000. Our results show that wet-dry cycles significantly modify the response of the susceptible bacteria to both the supernatant and cells of the antibiotic-producing bacteria, compared to constantly wet conditions. Notably , X. euvesicatoria shows increased protection against both the cells and supernatants of B. velezensis under wet-dry cycles, while P. syringae cells become more susceptible under wet-dry cycles. In addition, we observed a reciprocal interaction between P. syringae and B. velezensis , where P. syringae inhibits B. velezensis under wet conditions. Our findings highlight the important role of hydration conditions in shaping bacterial interference competition, providing valuable insights into the microbial ecology of water-unsaturated surfaces, with implications for applications such as biological control of plant pathogens and mitigating antibiotic resistance.IMPORTANCEOur study reveals that hydration conditions, particularly wet-dry cycles, significantly influence antibiotic-mediated competition between bacterial species. We revealed that the effectiveness of antibiotics produced by Bacillus velezensis against two susceptible bacterial species: Xanthomonas and Pseudomonas varies based on these hydration conditions. Unlike traditional laboratory environments, many real-world habitats, such as soil, plant surfaces, and even animal skin, undergo frequent wet-dry cycles. These conditions affect bacterial competition dynamics and outcomes, with wet-dry cycles providing increased protection for some bacteria while making others more susceptible. Our findings highlight the importance of considering environmental hydration when studying microbial interactions and developing biological control strategies. This research has important implications for improving agricultural practices and understanding natural microbial ecosystems., Competing Interests: The authors declare no conflict of interest.

Polycyclic aromatic compounds (PACs) are pervasive environmental contaminants derived from diverse sources including pyrogenic (e.g., combustion processes), petrogenic (e.g., crude oil), and biological origins. They are commonly found in gasoline, coal, and crude oil, reflecting their prevalence and varied origins in natural and anthropogenic activities. The aim of this study is to use Bacillus tropicus which is a spore-forming, gram-positive and facultative anaerobic bacteria, containing a gene for PACs degradtion. In this study bacterial sample was collected from women's vaginal discharge through streaking and spreading techniques. The DNA was extracted from bacterial culture and then the bacterium was identified through 16S rRNA which appeared to be B.tropicus. Then the computational analysis was conducted where the sequence similarity and functional analysis of alcohol dehydrogenase EutG protein from B.tropicus was analyzed through PSI-BLAT and SMART tool, respectively. The PSI-BLAST showed 100% query coverage score and 9 domains of alcohol dehydrogenase EutG protein were predicted through SMART tool. The quality of the protein was also assessed through ProQ server with a predicted LQ score of 8.091, a Maxsub score of - 0.350 and a z score of - 10.76. Then the phylogentic analysis was conducted to know the evolutionary relationship and closely related taxa. The 3D structure of the protein was predicted through SWISS MODEL and its quality was predicted through ERRAT with overall qauality factor of 98.708. The Ramachandran plot also predicted its quality and showed that 93.8% residues were in the most favored region. After this, 3D stucture of PACs were obtained from PubChem and molecular docking of the protein was performed with each of the compound. The lowest energy of - 10.3 was obtained with Indeno[1,2,3-cd] pyrene and the best docked complex was visulaized through discover studio to analyze its binding residues. Lastly, in-silico site-directed mutagenesis studies were performed which showed that the EutG gene (codes for alcoholic dehydrogenase) obtained from B. tropicus, will not get altered or have any decreasing effect on the enzyme's stability if it goes through any mutations. This suggests that B. tropicus can act as an efficient, non-virulent, and reliable candidate for the eco-friendly and cost-effective bioremediation of PACs., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: All methods were carried out in accordance with relevant guidelines and regulations. Study approval was obtained from the “Bioethical Committee of the Faculty of Science and Technology, University of Central Punjab. Consent to participate: All authors agreed to participate in this research. Informed consent was obtained from every participant., (© 2025. The Author(s).)

The high content of sucrose and raffinose reduces the prebiotic value of soybean oligosaccharides. Fructan sucrases can catalyze the conversion of sucrose and raffinose to high-value products such as fructooligosaccharides and melibiose. To obtain a fructan sucrase that can efficiently convert soybean oligosaccharides, we first mined the fructan sucrase gene from microorganisms in the coastal areas of Xisha Islands and Bohai Bay and then characterized the enzymatic and catalytic properties of the enzyme. Finally, recombinant extracellular expression of this gene was carried out in Bacillus subtilis . The results showed that a novel fructan sucrase, BhLS 39, was mined from Bacillus halotolerans . With sucrose and raffinose as substrates, BhLS 39 showed the optimal temperatures of 50 ℃ and 55 ℃, optimal pH 5.5 for both, and K cat / K m ratio of 3.4 and 6.6 L/(mmol·s), respectively. When 400 g/L raffinose was used as the substrate, the melibiose conversion rate was 84.6% after 30 min treatment with 5 U BhLS 39. Furthermore, BhLS 39 catalyzed the conversion of sucrose to produce levan-type-fructooligosaccharide and levan. Then, the recombinant extracellular expression of BhLS 39 in B . subtilis was achieved. The co-expression of the intracellular chaperone DnaK and the extracellular chaperone PrsA increased the extracellular activity of the recombinant BhLS 39 by 5.2 folds to 17 U/mL compared with that of the control strain. BhLS 39 obtained in this study is conducive to improving the quality and economic benefits of soybean oligosaccharides. At the same time, the strategy used here to enhance the extracellular expression of BhLS 39 will also promote the efficient recombinant expression of other proteins in B . subtilis .

Bacillus velezensis S141 helps soybean establish specific symbiosis with strains of Bradyrhizobium diazoefficiens to form larger nodules and improve nitrogen fixation efficiency. In this study, we found that the dry weight of soybean roots increased significantly in the presence of S141 alone under drought conditions. Hence, S141 improved the root growth of soybean under limited water supply conditions. S141 can produce some auxin, which might be involved in the improved nodulation. Inactivating IPyAD of S141, which is required for auxin biosynthesis, did not alter the beneficial effects of S141, suggesting that the root growth was independent of auxin produced by S141. Under drought conditions, soybean exhibited some responses to resist osmotic and oxidative stresses; however, S141 was relevant to none of these responses. Although the mechanism remains unclear, S141 might produce some substances that stimulate the root growth of soybean under drought conditions., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.)

A new strategy has been developed to successfully produce the active component danshensu ex vivo. For this purpose, phenylalanine dehydrogenase from Bacillus sphaericus was combined with the novel hydroxyphenylpyruvate reductase from Mentha x piperita, thereby providing an in situ cofactor regeneration throughout the conversion process. The purified enzymes were co-immobilized and subsequently employed in batch biotransformation, resulting in 60% conversion of 10 mM L-dopa within 24 h, with a catalytic amount of NAD + as cofactor. Furthermore, the bienzymatic system was implemented as a packed-bed reactor in continuous flow, achieving a conversion rate up to 80% with 60 min retention time. The process was further intensified by implementing a 48-h flow bioreaction. The biocatalysts demonstrated remarkable stability, retaining 62% of their initial activity at the end of the process. The final productivity of the isolated compound (96% purity) was calculated to be 1.84 g L -1  h -1 yielding a sustainable synthesis of danshensu. KEY POINTS: • Characterization of the hydroxyphenylpyruvate reductase from Mentha x piperita • Bi-enzymatic system in a cascade reaction to produce danshensu • Purification and isolation of the active compound danshensu., Competing Interests: Declarations. Ethical approval: This article does not contain any studies with human participants or animals performed by any of the authors. Conflict of interest: The authors declare no competing interests., (© 2025. The Author(s).)

The research highlights the importance of exploring endophytic microbiomes of medicinal plants to uncover their potential for secondary metabolite production and their role in the biosynthesis of host-derived compounds. This study was aimed to isolate leaf endophytic bacteria of Rauvolfia serpentina, investigate their antibacterial, antioxidant potentials and detect host-origin compound reserpine using Reverse Phase High-Performance Liquid Chromatography (RPHPLC). Untargeted analysis via Ultra High-Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HRMS/MS) was conducted for profiling main phytochemicals in the leaves and to explore potential bioactive compounds in bacterial extracts. Nine bacterial isolates were obtained from R. serpentina leaves. These isolates exhibited positive results in various biochemical tests including indole production, methyl red, Voges-Proskauer, citrate utilization, catalase and oxidase production, nitrate reduction, oxidative fermentation, and citrate reduction tests. Endophytic isolates RSLB3 and RSLB18 exhibited most potential antibacterial activity against tested human pathogenic bacteria and were identified as Bacillus sp. The extract of RSLB3 and RSLB18 also showed significant antioxidant activity compared to leaf extract. The total phenol content was similar in both these isolates while flavonoids content and DPPH scavenging activity was higher in isolate RSLB3. RPHPLC analysis confirmed the presence of reserpine in bacterial metabolites when compared to a standard reference. UHPLC-HRMS profiling unveiled a diverse range of host-derived compounds and reaction intermediates with known and unknown bioactive properties in leaf extract, RSLB3, and RSLB18. To our knowledge, this is the first study to achieve a comprehensive profiling., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Cyclic lipopeptides (CLPs) are potent secondary metabolites with diverse biological functions. Bacillus strains primarily produce CLPs of three key families, namely, iturins, fengycins, and surfactins, each comprising structural variants characterized by a cyclic peptide linked to a fatty acid chain. Despite extensive research on CLPs, the individual roles of these analogues and their proportion in driving biological activity have remained largely overlooked. In this study, we purified and chemically characterized CLP variants from Bacillus velezensis UMAF6639 and tested them individually for their antifungal and plant growth-promoting effects. We isolated 5 fractions containing iturin A analogues (from C 13 to C 17 ), 5 fengycin fractions (containing C 16 , C 17 , and C 18 fengycin A and C 14 , C 15 , C 16 , and C 17 fengycin B), and 5 surfactin fractions (from C 12 to C 16 ). We show how antifungal activity and seed radicle growth promotion relied on the lipopeptide structural variant and concentration based on the physiological ratio calculated for each lipopeptide variant. Notably, we found that the most toxic variants were the least abundant, which likely minimized autotoxicity while preserving bioactivity. This balance is achieved through synergistic interactions with more abundant, less aggressive analogues. Furthermore, certain fengycin and surfactin variants were shown to increase bacterial population density and exopolysaccharide production, crucial strategies for microbial competition with significant ecological impacts. In addition to advancing basic knowledge, our findings will support the development of precision biotechnological innovations, offering targeted solutions to drive sustainable food production and preservation strategies.

With rising concerns about antimicrobial resistance, the identification of new lead compounds to target multidrug-resistant bacteria is essential. This study employed a fast miniaturized screening to simultaneously cultivate and evaluate about 300 marine strains for biosurfactant and antibacterial activities, leading to the selection of the deep-sea Bacillus halotolerans BCP32. The integration of tandem mass spectrometry molecular networking and bioassay-guided fractionation unveiled this strain as a prolific factory of surfactins and nobilamides. Particularly, 84 nobilamide congeners were identified in the bacterial exometabolome, 71 of them being novel metabolites. Among these, four major compounds were isolated, including the known TL-119 and nobilamide I, as well as the two new nobilamides T1 and S1. TL-119 and nobilamide S1 exhibited potent antibiotic activity against various multidrug-resistant Staphylococcus strains and other Gram-positive pathogens, including the foodborne pathogen Listeria monocytogenes . Finally, in silico analysis of Bacillus halotolerans BCP32 genome revealed nobilamide biosynthesis to be directed by a previously unknown heptamodular nonribosomal peptide synthetase.

Background: Plastic pollution is a significant environmental problem caused by its high resistance to degradation. One potential solution is polyhydroxybutyrate (PHB), a microbial biodegradable polymer. Mexico has great uncovered microbial diversity with high potential for biotechnological applications. The best polymer producers tend to be isolated from environments that require survival adaptations from microorganisms, the high-producing Bacillus cereus strain saba.zh comes from refinery wastewater, the costs of production have been a limiting factor for biopolymer production, and one of the focuses of interest has been finding novel strains with better production or singular traits that help in industrial processes., Results: The isolates were taxonomically classified as Bacillus cereus MSF4 and Bacillus inaquosorum MSD1 from Mina, Nuevo Leon; B. cereus S07C; and Paenibacillis dendritiformis from the active volcano "El Chichonal" on Chiapas. The strains had growth temperatures ranging from 35 to 50 °C and pH tolerance values ranging from 3 to 9. The best PHB-producing strain, B. cereus MSF4, produced 0.43 g/kg PHB on orange peels, followed by B. inaquosorum MSD1 at 0.40 g/kg, B. cereus S07C at 0.23 g/kg and P. dendritiformis at 0.26 g/kg., Conclusions: The findings of this study affirm the potential of the Mexican isolated strains as PHB-producing organisms, enabling further studies to test their viability as industrial producers. The ability of P. dendritiformis and B. inaquosorum to synthetize PHB was also confirmed by the observations made providing novel evidence to consider these species as potential producers., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

In this study, five strains previously isolated from black liquor (BL) and vinasse (V) were tested to assess the most promising regarding its capacity of biosurfactant production. For that, four factorial designs of two factors at two levels (2 2 ) were run for each strain. Selected factors were the production time and the composition media, while the surface tension reduction and optical density were the responses variables. Production media prepared just with V or BL exhibited minimal biosurfactant production, while better results were achieved when media were formulated with nutrient broth (NB), olive oil (Oo), and a percentage of V or BL. Result showed that Bacillus sp. b1 reported the highest surface tension reduction (29.39 mN/m and OD = 8.7) using 5 % BL, 5 g/l NB and 11.5 g/l Oo during 2 to 4 days followed by Lactobacillus sp. a1 (19.47 mN/m and OD = 10.87) using 1 % V, 1 g/l NB and 2.5 g/l Oo during 2 to 4 days. The other strains also showed promising results (Alkalihalobacillus sp. b2: 16.91 mN/m; Pichia sp. a6: 13.8 mN/m; Lactobacillus sp. a5: 13.66 mN/m). This study provides crucial insights regarding the ability of these particular extremophiles strains of producing biosurfactants with the hope of optimizing the process and be able to scale up the production. This will be a huge step towards the development of environmentally friendly bioproduct which can eventually compete with synthetic surfactants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study reports the isolation and characterization of highly resistant bacterial and microalgal strains from an Egyptian wastewater treatment station to cyanide-containing compounds. The bacterial strain was identified as Bacillus licheniformis by 16S rRNA gene sequencing. The isolate removed up to 1 g L -1 potassium cyanide, 3 g L -1 benzonitrile, and 1 g L -1 sodium salicylate when incubated as 10% v/v in MSM at 30 ℃. However, it failed to degrade potassium thiocyanate at all tested concentrations. The microalgal isolate was identified by electron microscopy as a strain of Chlorella spp.. Algal toxicity was tested by incubating the microalgae as 6% v/v in MSM containing 2 g L - 1 NaHCO 3 with increasing concentrations of the pollutants. Results showed that 0.05 g L -1 KCN, 1.5 g L -1 benzonitrile, 5 g L  -1 KSCN, and 5 g L -1 sodium salicylate inhibited 93%, 96%, 75%, and 21% of algal growth, respectively. In a continuous stirred photobioreactor, the bacterial-microalgal microcosm detoxified synthetic wastewater containing 0.2 g L -1 KCN, 0.1 g L -1 benzonitrile, and 0.5 g L -1 sodium salicylate in 3.5 days of hydraulic retention time. System failure was recorded when the KCN concentration was increased to 0.25 g L -1 . The effluent had no inhibitory effect on the germination of Lepidium sativum seeds in phytotoxicity testing. Temperature, pH, and chitosan effects were assessed on the algal/bacterial settleability. Statistical analysis showed no significant difference between the tested parameters. The microcosm represents a potential candidate for the treatment of industrial wastewater containing cyanide compounds., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: This is an observational study. The Faculty of Pharmacy, Cairo University Research Ethics Committee has confirmed that no ethical approval is required., (© 2025. The Author(s).)

In recent years, it has become widely acknowledged that heavy metals are often present in oil-contaminated sites. This study utilized three specific types of microorganisms with different functions to construct a composite bacterial consortium for treating lubricant-Cr(VI) composite pollutants. The selected strains were Lysinbacillus fusiformis and Bacillus tropicus. The Back Propagation Neural Network-genetic algorithm was employed to optimize the secondary bacterial addition time to 67 h and the strain ratio to 2:1. The optimized process involved the use of 4.6 g/L glucose and ammonium oxalate as electron donors. After 6 days of treatment with the composite consortium, the removal rates of 1500 mg/L lubricating oil and 50 mg/L chromium reached 90.3% and 84.2%, respectively. Initial analysis using three-dimensional fluorescence to examine the changes in extracellular polymers in the bacteria when exposed to chromium-lubricating oil, showed that 30 mg/L Cr(VI) could induce the secretion of extracellular protein-like substances. These substances may be directly or indirectly involved in the biological detoxification mechanism of chromium. The synergistic removal of complex pollutants has the potential to transform previous "unilateral" removal studies and enhance bioremediation efficiency., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Nature B.V.)

The coexistence of microplastics and heavy metals in soil can lead to more intricate environmental effects. While plant growth-promoting bacteria have been widely recognized for enhancing the remediation of heavy metal-contaminated soils, little research has been conducted to investigate whether they can alleviate the stress of microplastic-heavy metal composite contamination on plants. We investigated the effects of isolated and screened plant growth-promoting bacteria on the growth and cadmium （Cd） accumulation of Hybrid pennisetum under the composite pollution of Cd and polypropylene （PP） with different particle sizes （6.5 and 830 μm） in pot experiments and analyzed their effects on the composition of rhizosphere bacterial communities using high-throughput sequencing. Seven strains of bacteria were isolated and screened from soil contaminated with heavy metal-microplastic composites, identified as Enterobacter and Bacillus spp. All exhibited plant growth-promoting characteristics, including IAA production, siderophores, phosphorus solubilization, and potassium solubilization. Inoculation of plant growth-promoting bacteria increased the length and dry weight of H. pennisetum , effectively alleviating the stress caused by PP+Cd compound pollution. Plant growth-promoting bacteria increased soil available potassium and available phosphorus content, mitigating the decrease in soil mineral nutrients caused by PP+Cd composite pollution. PP+Cd compound pollution and plant growth-promoting bacterial inoculation affected the composition of the rhizosphere bacterial community of H. pennisetum , influencing dominant populations such as Proteobacteria, Firmicutes, and Actinobacteria. This study observed that the isolated and screened plant growth-promoting bacteria can effectively alleviate the plastic-heavy metal complex pollution caused by H. pennisetum. This provides a theoretical basis and data support for the remediation of microplastic heavy metal complex-contaminated soil biological pollution.

Bacillus altitudinis is a well-known beneficial microorganism in plant rhizosphere, capable of enhancing plant growth and salt tolerance in saline soils. However, the mechanistic changes underlying salt tolerance in B. altitudinis at the level of post-translational modifications remain unclear. Here, diverse lysine modifications including acetylation, succinylation, crotonylation, and malonylation were determined in the B. altitudinis response to salt stress by immunodetection, and the acetylation level greatly increased under salt stress. The in-depth acetylome landscape showed that 1032 proteins in B. altitudinis were differentially acetylated under salt stress. These proteins were involved in many physiological aspects closely related to salt tolerance like energy generation and conversion, amino acid synthesis and transport, cell motility, signal transduction, secretion system, and repair system. Moreover, we also identified the differential acetylation of key enzymes involved in the major osmolyte biosynthesis and conversion and antioxidant defenses. Thiol peroxidase (TPX), a key protective antioxidant enzyme, had 3 upregulated acetylation sites (K7/139/157) under salt stress. Site-specific mutations demonstrated that K7/139/157 acetylation strongly regulated TPX function in scavenging intracellular ROS, thereby impacting bacterial growth under salt stress. To our knowledge, this is the first study showing that bacteria adaptation to salt stress occurs at the level of PTMs.

Bacillus cyclic lipopeptides (CLP), part of the three main families-surfactins, iturins, and fengycins-are secondary metabolites with a unique chemical structure that includes both peptide and lipid components. Being amphiphilic compounds, CLPs exhibit antimicrobial activity in vitro, damaging the membranes of microorganisms. However, the concentrations of CLPs used in vitro are difficult to achieve in natural conditions. Therefore, in a natural environment, alternative mechanisms of antimicrobial action by CLPs are more likely, such as inducing apoptosis in fungal cells, preventing microbial adhesion to the substrate, and promoting the death of phytopathogens by stimulating plant immune responses. In addition, CLPs in low concentrations act as signaling molecules of Bacillus 's own metabolism, and when environmental conditions change, they form an adaptive response of the host bacterium. Namely, they trigger the differentiation of the bacterial population into various specialized cell types: competent cells, flagellated cells, matrix producers, and spores. In this review, we have summarized the current understanding of the antimicrobial action of Bacillus CLPs under both experimental and natural conditions. We have also shown the relationship between some regulatory pathways involved in CLP biosynthesis and bacterial cell differentiation, as well as the role of CLPs as signaling molecules that determine changes in the physiological state of Bacillus subpopulations in response to shifts in environmental conditions.

The study explores the potential of an indigenous halo-tolerant microbe identified as Bacillus spp. SSAU-2 in enhancing soil fertility and promoting plant growth for sustainable agricultural practices under the influence of multiple abiotic stresses such as Cr(VI), high salinity, and artificial drought condition. The study investigated various factors influencing IAA synthesis by SSAU-2, such as pH (5 to 11), salinity (10 to 50 g/L), tryptophan concentration (0.5 to 1%), carbon (mannitol mand lactose), and nitrogen sources (peptone and tryptone). The highest IAA concentration was observed at pH 10 (1.695 mg/ml) and pH 11 (0.782 mg/ml). IAA synthesis was optimized at a salinity level of 30 g/l, with lower and higher salinity levels resulting in decreased IAA concentrations. Notably, the presence of mannitol and lactose significantly augmented IAA synthesis, while glucose and sucrose had inhibitory effects. Furthermore, peptone and tryptone played a pivotal role in enhancing IAA synthesis, while ammonium chloride exerted an inhibitory influence. SSAU-2 showed a diverse array of capabilities, including the synthesis of gibberellins, extracellular polymeric substances, siderophores, and hydrogen cyanide along with nitrogen fixation and ammonia production. The microbe could efficiently tolerate 45% PEG-6000 concentration and effectively produce IAA in 15% PEG concentration. It could also tolerate high concentration of Cr(VI) and synthesize IAA even in 50 ppm Cr(VI). The findings of this study provide valuable insights into harnessing the potential of indigenous microorganisms to promote plant growth, enhance soil fertility, and establish sustainable agricultural practices essential for restoring the health of ecosystems., Competing Interests: Declarations. Ethical approval: Not applicable. Consent of participate: Not applicable Conflict of interest: There is no conflict of interest for this manuscript. The authors declare that they have no known competing financial. Competing of interest: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

This study employs Taguchi design of experiments (DOE) to optimize biosurfactant yield by analyzing the impact of various input parameters. Signal-to-noise ratio analysis was utilized for optimization, corroborated by ANOVA findings. Regression equations depicted response behaviour and are validated through a confirmation test. Taguchi methodology identified optimal conditions for maximum biosurfactant yield: agitation (180 rpm), inoculum size (2%), beef extract (5 g/L), diesel (20 ml/L), peptone (5 g/L), NaCl (7 g/L), incubation time (4 days), pH (7.9), and yeast extract (6 g/L). This yielded an 8.33% increase to 1.53 g/L, with initial optimum parameters projecting 1.41 g/L. ANOVA ranked and quantified control factor contributions, revealing agitation's significant (31.41%) impact on yield. The study underscores the viability of Taguchi's optimal conditions for substantial yield improvement within specific ranges. The strong alignment between expected and experimental yields affirmed the reliability of developed models for optimal yield selection. This study underscores the power of statistical techniques like Taguchi DOE and ANOVA in systematically enhancing biosurfactant production by Bacillus aryabhattai SPS1001 and paves the way for future advancements in bioprocess optimization., Competing Interests: Declarations. Ethical Statement: This article does not contain any studies with human participants or animals performed by any of the authors. Consent to Participate: Not applicable. Consent for Publication: Not applicable. Competing Interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Water pollution with toxic hexavalent chromium, Cr(VI), is an environmental threat that has a direct impact on living organisms. The use of microorganisms from microbial mats to remove Cr(VI) has scarcely been investigated. Here, we isolated aerobic heterotrophic bacteria from a Cr-polluted microbial mat found in a mining site in Oman, and investigated their ability to remove Cr(VI), and the underlying mechanism(s) of removal. All isolates fell phylogenetically into the genera Enterobacter, Bacillus, and Cupriavidus, and could completely remove 1 mg L -1 Cr(VI) in 6 days. The strains could tolerate up to 2000 mg L -1 Cr(VI), and exhibited the highest Cr(VI) removal rate at 100 ± 9 mg L -1 d -1 . Using scanning electron microscopy (SEM) coupled with elemental analysis, the strains were shown to adsorb Cr(VI) at their cell surfaces. The functional groups OH, NH 2 , Alkyl, Metal-O, and Cr(VI)-O were involved in the biosorption process. In addition, the strains were shown to reduce Cr(VI) to Cr(III) with the involvement of chromate reductase enzyme. We conclude that the aerobic heterotrophic bacteria isolated from Cr-polluted microbial mats use biosorption and bioreduction processes to remove Cr(VI) from wastewater., Competing Interests: Declarations. Ethical Approval: No human or animal subjects were used in this study and no ethical approval was required. Consent to Participate: No human or clinical data was used in this study. Consent to Publish: All the data presented was generated and original. No image or figure retrieved from other research. Competing Interests: The authors have no relevant financial or non-financial interests to disclose. Conflict of Interest: The authors declare that they have no conflict of interest., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Bacillus velezensis can produce various secondary metabolites, such as the antibacterial compound iturin A and the coagulation-promoting menaquinone-7 (MK-7). To enhance the economic feasibility of the fermentation process, a co-production strategy, involving the simultaneous production of MK-7 and iturin A by Bacillus velezensis ND, was investigated in this study. Firstly, the effects of cultivation temperature and initial pH on the synthesis of MK-7 and iturin A were investigated. Considering the co-production of iturin A and MK-7, the optimal temperature and pH were determined as 32 °C and 7, respectively. Subsequently, important nutrients for the co-production process were investigated. It was observed that glycerol, soybean meal, yeast extract, and L-glutamate had a significant effect on the co-produce process. An optimal medium composed of glycerol (72.19 mL L -1 ), L-glutamate (1.4 g L -1 ), yeast extract (16.88 g L -1 ), and soybean meal (130.95 g L -1 ) was obtained by response surface methodology (RSM). This co-produce process was further scaled up in a biofilm reactor, and the maximum concentration of MK-7 and iturin A reached 46.88 mg L -1 and 5.58 g L -1 , respectively. Finally, we established an effective method for separately extracting the two metabolites from the fermentation broth. The superiority of this co-production fermentation strategy demonstrates its significant potential for industrial production., Competing Interests: Declarations. Ethical Approval: This article does not contain any studies with human participants by any of the authors. Consent to Participate: Not applicable. Consent for Publication: Not applicable. Conflict of Interest: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Listeria monocytogenes, a pathogenic bacterium causing zoonotic diseases, necessitates the urgent search for novel anti-Listeria monocytogenes drugs due to the continuous emergence of drug-resistant bacteria. In this study, we isolated and identified a bacteriocin-producing strain CM7-4 from seawater as Bacillus velezensis through 16S rRNA sequence analysis. Moreover, we successfully purified a novel bacteriocin named PCM7-4 from Bacillus velezensis CM7-4. The molecular weight of PCM7-4 was determined to be 40,228.99 Da. Notably, PCM7-4 exhibited broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria with a minimum inhibitory concentration (MIC) of 5.625 μg/mL against Listeria monocytogenes specifically. It demonstrated heat resistance and high stability within the pH range of 2-12 while being sensitive to proteinase K degradation without any observed hemolytic activity. Furthermore, SEM analysis revealed that PCM7-4 effectively inhibited biofilm formation and disrupted cell membranes in Listeria monocytogenes cells. Transcriptome analysis revealed that PCM7-4 exerts an impact on genes associated with crucial metabolic pathways, encompassing the biosynthesis of secondary metabolites, phosphotransferase systems (PTS), and starch/sucrose metabolism. These findings highlight the significant potential of bacteriocin PCM7-4 for the development of effective antimicrobial interventions targeting food-borne pathogenic bacteria., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Microbial natural products are widely explored for their therapeutic potential. Understanding the underlying evolutionary and adaptive forces driving their production remains a fundamental question in biology. Amphiphilic cyclic lipopeptides (CLPs), a prominent category of bacterial specialized metabolites, show strong antimicrobial activity, particularly against phytopathogens. It is thus assumed that these compounds are deployed by soil- or rhizosphere-dwelling bacteria as microbial weapons in competitive natural environments. Here, we challenge this reductionist perspective and present evidence that Bacillus CLPs are prominent chemical mediators of ecological interactions. They help Bacillus to communicate, compete, defend against predators, or cooperate and establish mutualistic relationships with other (micro)organisms. Additional parallel examples are highlighted in other genera, such as Pseudomonas. This broader perspective underscores the need for further investigation into the role of CLPs in shaping the adaptive strategies of key rhizobacterial species., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Pseudomonas and Bacillus are dominant microorganisms to widely distributes in asphalt pavement structure. Microbial degradation leads to asphalt aging, and causes its performance deterioration, reducing the durability of asphalt pavement. To better understand the degradation behaviors of dominant microorganisms on asphalt, and reveals their microbial aging mechanisms on asphalt, the effects of microbial degradation on micromorphology, chemical functional group, component and microstructure of asphalt were discussed. Results indicate that main damages of microbial degradation start from asphalt surface and then permeates into its interior. Microorganisms degrade light components of asphalt as nutrients and decompose them into CO 2 and H 2 O through oxidation reactions, but exhibit limited degradation ability to macromolecular components. Microbial degradation causes the content changes of asphalt components, altering the colloidal structure of asphalt. Microorganisms destroy the continuity of asphalt surface and increase surface roughness of asphalt. This study provides a new insight into microbial aging mechanism of asphalt., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A high polyglutamic acid (γ-PGA) producing strain of Bacillus natto UV-40-50 was screened by ultraviolet mutagenesis treatment and identified as still belonging to the Bacillus specie. The optimal fermentation medium composition for solid state fermentation (SSF) of B. natto strain UV-40-50 strain was determined by one-way analysis of variance, under which the yield of γ-PGA was 55.19 g/kg, and the presence and molecular weight of γ-PGA in the γ-PGA-purified samples were determined by a series of characterizations. The purification ability of the unseparated solid fermentation product (SFP) on ammonia nitrogen and nitrite in the water column, as well as its effect on soil water retention, germination rate and seedling length of lettuce and cabbage were further investigated. The results showed that the addition of 1 g/m3 SFP could effectively remove more than 60 % of ammonia nitrogen and more than 40 % of nitrite in the water body; the addition of 0.01 % SFP could increase the water retention capacity of cabbage soil by 2.13 times, and increase the water retention capacity of lettuce soil by 12 %; at the same time, the SFP could also significantly increase the germination rate and seedling length of both cabbage and lettuce., Competing Interests: Declaration of Competing Interest We declare that have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

The widespread retirement of crystalline silicon solar cells in coming years poses a significant obstacle to sustainable development. Arable soils have experienced a gradual decline in available silicon levels due to intensive agricultural production. Therefore, it is feasible to repurpose recovered waste crystalline silicon cells below cell-reuse benchmark into agriculturally usable resources. This study investigates the impact of photovoltaic crystalline silicon-derived fertilizer (Si group), external silicate-dissolving bacteria (Bac group), and their combination (All group) on early rice nutrient uptake, growth development, and soil physical and chemical properties through a 45-day potting experiment. The combined addition of silicon fertilizer and bacteria significantly improved soil nitrification process (nitrate nitrogen NO 3 -N increased by 73.5%) and soil organic matter content by 16.2%. The increases in soil-available silicon (by 14.9%) and total potassium (by 19%) in the All and Si were significant. For rice growth, the addition of silicon fertilizer did not have a positive effect on dry matter accumulation and plant height possibly due to the Si threshold effect or K stress. However, the chlorophyll content of the Bac and All treatment groups was enhanced by 25% and 29%, respectively, suggesting the positive effect of bacteria on soil nitrogen utilization. The absorption of potassium by the plants was positively correlated with silicon, and the accumulation of silicon reduced the carbon content of the rice's aboveground parts by 7.3% to 9.0%. The study provides a feasible solution of recycling and reusing waste crystalline silicon in agricultural applications, and the results also have indicative significance for the sustainable rice production under non-stress environmental conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Arsenic (As) contamination in agricultural groundwater and soil is a significant economic and health problem worldwide. It inhibits soybean (Glycine max (L.) Merr.) nodulation and biological nitrogen fixation in symbiosis with Bradyrhizobium japonicum E109 (E109), a commonly used rhizobial strain for commercial biofertiliser formulation in Argentina. In the context of sustainable and climate-smart agriculture promoted by FAO, co-inoculating legumes with As-tolerant plant growth-promoting bacteria (PGPB) is suggested as a superior alternative to single inoculation. This study aimed to evaluate the impact of As on plant growth-promoting (PGP) traits -siderophore and indole acetic acid production, phosphate solubilisation, diazotrophic activity and hydrolytic enzymes activity- in E109 and three other PGPB strains: Pseudomonas sp. AW4 (AW4), Bacillus pumilus SF5 (SF5) and Bacillus toyonensis SFC 500-1E (Bt). In addition, bacterial compatibility and adhesion on soybean seed were evaluated. Arsenic significantly reduced PGP traits of E109 even at low concentrations, AW4's traits remained unchanged, while those of SF5 and Bt traits were affected (positively or negatively) only at the highest concentrations tested (500 µM arsenate, 250 µM arsenite). All PGPB strains were compatible with E109 under both control and As-stress conditions. Soybean seed adhesion was reduced for E109, only under As stress. Findings suggest that the effect of As on PGP traits is highly strain-dependent and influenced by As concentration and speciation. AW4, SF5, and Bt strains show promise for co-inoculation with E109 in soybean cultivation., Competing Interests: Declarations. Competing Interests: The authors declare no competing interests. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent to publication: Not applicable., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The cultivation of common beans (Phaseolus vulgaris L.) in semi-arid regions is affected by drought. To explore potential alleviation strategies, we investigated the impact of inoculation with Bacillus velezensis, and the application of acetylsalicylic acid (ASA) via foliage application (FA), which promote plant growth and enhance stress tolerance. A split-split-plot experiment with four replications was conducted, featuring two irrigation levels: full watering (FW, 100% of plant water requirements) and deficit watering (DW, 70% of plant water requirements) as a main plot, two ASA levels (No foliage application (NFA) 0 and 0.5 mM) as sub plot, and bacterial inoculation (BI) versus non-bacterial inoculation (NBI) as sub-sub plot. Results showed that the highest grain yield was achieved with the ASA + BI under FW (3270 kg ha - ¹), a 56% increase compared to the control (2094 kg ha - ¹). Under DW, the ASA + BI increased yield by approximately 30%. ASA significantly increased relative water content under deficit watering, achieving 84% with BI. Chlorophyll a content peaked at 3.11 mg g - 1 with full watering, and chlorophyll b content increased by up to 23.8% under deficit watering, indicating improved photosynthetic capacity. Malondialdehyde and hydrogen peroxide levels were reduced to 10.88 and 14.81 µmol g - ¹ fresh weight, respectively, in ASA + BI treatments, demonstrating reduced oxidative stress. Antioxidant enzyme activities were significantly elevated in treated plants under DW. This study demonstrates the potential of microbial and hormonal treatments in boosting drought tolerance in common beans, providing a viable approach for sustaining crop performance under stress conditions., Competing Interests: Declarations. Ethics approval and consent to participate: All required permits have been received from University of Tehran. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Some insects have evolved beneficial relationships with intestinal microbes for sex pheromone production to communicate with conspecifics effectively. However, it is not clear whether the sex pheromone synthesis activity of intestinal microbes can be controlled by the host, and the molecular mechanisms need to be further unraveled. In this study, we find that rectal gland Bacillus species of male Bactrocera dorsalis specifically produce sex pheromones in the evening, which is significantly associated with glucose levels. In vitro Bacillus culture assays show that glucose levels significantly influence the amount of sex pheromone produced. Comparative rectal gland transcriptome analysis reveals that the expressions of the alpha-galactosidase gene (GLA), a Bactrocera dorsalis transcription factor (BDTF), and a pigment-dispersing factor (PDF) are responsible for producing glucose. Our findings reveal that the PDF-BDTF-GLA module influences the intestinal-microbe-produced sex pheromone by regulating glucose levels and advance our understanding of interactions between insects and their intestinal microbes., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Azo dye wastewater has garnered significant attention from researchers because of its association with high-temperature, high-salt, and high-alkali conditions. In this study, consortium ZZ efficiently decolorized brown D3G under halophilic and thermophilic conditions. he results indicated that consortium ZZ, which was mainly dominated by Marinobacter, Bacillus, and Halomonas, was achieved decolorization rates ranging from 1 to 10% at temperatures between 40 °C and 50 °C, while maintaining a pH range of 7 to 10 for direct brown D3G degradation. Through the comprehensive utilization of UV-vis spectral analysis, Fourier transform infrared (FTIR), gas chromatography mass spectrometric (GC-MS) techniques, as well as metagenomic analysis, the decolorization and degradation pathway of direct brown by consortium ZZ was proposed. The azo dye reductase, lignin peroxidase, and laccase were also highly expressed in the decolorization process. Additionally, phytotoxicity tests using seeds of Cucumis sativus and Oryza sativa revealed that the intermediates generated showed no significant toxicity compared with distilled water. This investigation elucidated the pivotal contribution of consortium ZZ to azo dye degradation and provided novel theoretical insights along with practical guidance for azo dye treatment at halo-thermophilic conditions., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024. The Author(s), under exclusive licence to Springer Nature Japan KK.)

Type 2 Diabetes continues to be one of the major public health issues worldwide without any sustainable cure. The modulation of gut microbiota is believed to be caused by probiotic bacteria and several probiotic strains have previously shown antidiabetic activity. The present study aims to isolate potential probiotic bacteria from traditionally used fermented rice beer of Assam, India and to investigate its anti-hyperglycemic effect. Of the 20 isolated bacterial isolates, 5 isolates showed potential probiotic activities, of which, 2 isolates viz. Bacillus sp. FRB&#95;A(A) and Acetobacter sp. FRB&#95;B(S) showed good in vitro anti-oxidant and anti α-glucosidase activities. Based on the in vitro results, isolate Bacillus sp. FRB&#95;A(A) was further used to evaluate the antidiabetic activity in streptozotocin induced diabetic rat model. After 21 days, the blood glucose level in diabetic rats with probiotic administration significantly lowered from 458.00 ± 46.62 mg/dl to 108.20 ± 6.76 mg/dl (p < 0.001), whereas, in diabetic rats without probiotic remained high (576.20 ± 29.48 mg/dl). On analyzing the endogenous antioxidant profile in various tissues of the experimental rats, reduced lipid peroxidation, glutathione level and superoxide dismutase and glutathione peroxidase activity were observed in probiotic administered rats in comparison to the streptozotocin treated diabetic controls. In conclusion, the bacteria Bacillus sp. FRB&#95;A(A) isolated from fermented rice beer possesses probiotic attributes and exhibits significant anti-hyperglycemic activities., Competing Interests: Declarations. Ethical approval: The animal experiments were carried out in accordance with the guidelines of the Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA), and the Institutional Animal Ethics committee of Assam down town University, Guwahati, Assam (Reg. number 1574/PO/Re/S/11/CCSEA) and was approved by the Committee vide Approval No: AdtU/IAEC/2023/003 dated 08/07/2023) Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Polyurethane (PU), a widely used and durable plastic, persists in the environment, resulting in significant waste management challenges. Therefore, developing eco-friendly degradation technologies, such as screening for efficient biodegrading microorganism strains, is urgently needed to address this issue. Bacillus velezensis MB01B, an efficient polyester PU-degrading bacterium, was isolated from landfill soil and demonstrated the ability to degrade 91.4% of 0.75% Impranil DLN within 24 h under the optimal conditions (30.5 °C and initial pH 6.5). To assess the degradation capability of MB01B, three PU substrates of increasing complexity-Impranil DLN film, polyester thermoplastic polyurethane (TPU) film, and commercial PU desk mat-were tested; after 30 days, weight losses of 24.8%, 18.3%, and 5.4% were observed, respectively. In addition, SEM images showed significant morphological changes on the surface of these PU materials after treatment with MB01B. FTIR analysis of Impranil DLN films following degradation showed reductions in key functional groups (ester and urethane); and the identification of neopentyl glycol and 1,6-hexanediol as degradation intermediates suggested MB01B possesses the capability to hydrolyze ester and urethane bonds. Concurrently, genome sequencing combined with RT-qPCR identified several enzymes, including urethanases and esterases/lipases, involved in PU degradation. Based on these results, the pathway for MB01B to degrade Impranil DLN was inferred. Finally, MB01B was successfully formulated into a solid microbial inoculum with favorable storage properties and used for in-situ degradation of the commercial PU materials (Impranil DLN films, TPU films and PU desk mats) in landfill soil, underscoring its potential for the in-situ biological treatment of PU plastic wastes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lin Li reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The process of altering the microbial-induced carbonate precipitation (MICP) by adding additives has been extensively studied. The impact of polysaccharides, as an important component of bacteria, still requires deeper exploration on MICP. This work thus focuses on two types of sugars, sodium alginate (SA) and trehalose (Tre), to explore their effects on biomineralization of carbonate induced by Bacillus pumilus Z6. The results show that B. pumilus Z6 can raise the environmental pH and increase the supersaturation of carbonate and bicarbonate ions through carbonic anhydrase. The presence of organic functional groups and the negative carbon isotope signatures in minerals provide evidence of microbial involvement. Tre and SA do not change the mineral phase, which mainly consists of hollow rice-like granular vaterite and irregular calcite. Tre is conducive to the formation of calcite, whereas the carboxyl groups in SA contribute to the stability of vaterite. Both Tre and SA enhance the removal rate of calcium ions; however, SA is more effective for this purpose. Furthermore, mineralization experiments with calcium alginate gel tablets indicate that SA can attract calcium carbonate to nucleate on its surface. This research offers significant insights into biomineralization processes and introduces novel perspectives for advancing MICP technology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The burgeoning global mushroom industry has precipitated challenges related to the efficient and sustainable utilization of spent mushroom substrate (SMS). Composting is regarded as an efficient way for the ecological utilization of SMS. The addition of microbial inoculants can promote the composting process and improve the quality of compost products. This study introduced two bacterial inoculants, Bacillus paralicheniformis HL-05 (BP) and Streptomyces thermoviolaceus LC-10 (ST), into the composting process of SMS. The impact of these inoculants was evaluated through analyses of physicochemical properties, lignocellulose degradation, and high-throughput sequencing to elucidate their ecological roles and optimize the composting process. The results suggest that inoculation with BP and ST significantly prolonged the thermophilic stage by 2-3 days, representing an increase of 22.22-33.33%. Moreover, it boosted the degradation rates of cellulose, hemicellulose, and lignin by 18.37-29.77%, 35.74-50.43%, and 40.32-40.83%, respectively, compared to the control. Furthermore, inoculation rapidly altered the microbial community structure during the rapid temperature-rising stage and strengthened interconnections among composting microorganisms. The microbial inoculation substantially enhanced the proliferation of thermophilic lignocellulose-degrading microorganisms during the thermophilic stage, thereby facilitating the utilization of lignocellulose. This study proposes a novel and effective strategy for SMS composting using microbial inoculants., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Guo-Qing Zhang reports financial support was provided by Beijing University of Agricultur. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Plastic films are extensively utilized in agriculture, construction, and manufacturing, with their annual production reaching staggering figures. Addressing the global plastic pollution crisis is imperative. One promising approach is the augmentation of plastic films degradation through microbial agents. Consequently, we undertook composting experiments employing various plastics, including Polyethylene (PE), Poly lactic acid (PLA), and a treatment without plastic films addition (CK), mixed with kitchen waste. Employing bipartite association networks and difference significance analysis methods, we scrutinized the impact of different plastics on the microbial community within the compost piles. There were significant disparities in the microbial community composition among three composting piles. To pinpoint the key microorganisms responsible for PLA degradation, we conducted a comparative analysis of microbial species present on PLA compost piles and PLA film surfaces (PLAS), utilizing variance analysis, co-occurrence network analysis, and Spearman's correlation analysis. Our findings identified Bacillus as the pivotal microorganism involved in PLA degradation. Furthermore, employing function prediction by PICRUSt 2, we identified K00016 as the crucial gene facilitating PLA degradation by Bacillus. Subsequently, employing strain screening techniques, we isolated a highly effective PLA-degrading bacterium, Bacillus amyloliquefaciens strain ML274. The PLA films degradation rate of ML274 reached 3.18%. and other strains was lower than 3.0%. Thus, Bacillus emerges as the primary microorganism driving PLA degradation, emphasizing the significance of focusing on Bacillus genus microorganisms in the development of plastic-degrading bacterial agents for future endeavors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Root exudates can benefit plant growth and health by reshaping the rhizosphere microbiome. Whether nanoparticles biosynthesized by rhizosphere microbes play a similar role in plant microbiome manipulation remains enigmatic. Herein, we collect elemental selenium nanoparticles (SeNPs) from selenobacteria associated with maize roots. In vitro and soil assays show that the SeNPs enhanced plant performance by recruiting plant growth-promoting bacteria (e.g., Bacillus) in a dose-dependent manner. Multiomic profilings unravel a cross-kingdom-signaling cascade that mediates efficient biosynthesis of SeNPs by selenobacteria. Specifically, maize roots perceive histamine signaling from Bacillus spp., which stimulates the plant to produce p-coumarate via root exudation. The rpoS gene in selenobacteria (e.g., Pseudomonas sp. ZY71) responds to p-coumarate signaling and positively regulates the biosynthesis of SeNPs. This study demonstrates a novel mechanism for recruiting host-beneficial soil microbes by microbially synthesized nanoparticles and unlocks promising possibilities for plant microbiome manipulation., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background/objectives: Bacillus velezensis has recently received increased attention as a potential biological agent because of its broad-spectrum antagonistic capacity against harmful bacteria and fungi. This study aims to thoroughly analyze the genomic characteristics of B. velezensis BRI3, thereby providing theoretical groundwork for the agronomic utilization of this strain., Methods: In this work, we evaluated the beneficial traits of the newly isolated strain B. velezensis BRI3 via in vitro experiments, whole-genome sequencing, functional annotation, and comparative genomic analysis., Results: B. velezensis BRI3 exhibits broad-spectrum antifungal activity against various soilborne pathogens, displays inhibitory effects comparable to those of the type strain FZB42, and exhibits particularly effective antagonism against Sclerotinia sclerotiorum (Lib.) de Bary. Whole-genome sequencing and assembly revealed that the genome of BRI3 contains one chromosome and two plasmids, which carry a large amount of genetic information. Moreover, 13 biosynthetic gene clusters (BGCs) involved in the biosynthesis of secondary metabolites were predicted within the BRI3 genome. Among these, two unique BGCs (cluster 11 and cluster 13), which were not previously reported in the genomes of other strains and could potentially encode novel metabolic products, were identified. The results of the comparative genomic analysis demonstrated the genomic structural conservation and genetic homogeneity of BRI3., Conclusions: The unique characteristics and genomic data provide insights into the potential application of BRI3 as a biocontrol and probiotic agent.

Plant-beneficial Pseudomonas and Bacillus have been extensively studied and applied in biocontrol of plant diseases. However, there is less known about their interaction within two-strain synthetic communities (SynCom). Our study revealed that Pseudomonas protegens Pf-5 inhibits the growth of several Bacillus species, including Bacillus velezensis. We established a two-strain combination of Pf-5 and DMW1 to elucidate the interaction. In this combination, pyoluteorin conferred the competitive advantage of Pf-5. Noteworthy, pyoluteorin-deficient Pf-5 cooperated with DMW1 in biofilm formation, production of metabolites, root colonization, tomato bacterial wilt disease control, as well as in cooperation with beneficial bacteria in tomato rhizosphere, such as Bacillus spp. RNA-seq analysis and RT-qPCR also proved the pyoluteorin-deficient Pf-5 mutant improved cell motility and metabolite production. This study suggests that the cooperative effect of Bacillus-Pseudomonas consortia depends on the balance of pyoluteorin. Our finding needs to be considered in developing efficient SynCom in sustainable agriculture., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Formononetin is a natural flavonoid existing widely in plants with many pharmacological effects. However, its application is limited by structure, poor water solubility and low bioavailability. In this study, Bacillus velezensis LQ5 was isolated from the inter-root soil of Glycyrrhiza uralensis Fisch for the first time and formononetin was firstly structurally modified by whole-cell catalysis of LQ5 to obtain formononetin-7-O-β-D-glucoside (FG), formononetin-7-O-β-(6''-O-succinyl)-D-glucoside (FGS) and formononetin-7-O-phosphate (FP). The selective preparation of the three products was achieved by adjusting the content of yeast extract, type and content of sugars, metal ions, pH and ATP content. The result confirmed that FP had the ideal drug-likeness properties and showed a greater ability to reduce intracellular reactive oxygen species levels and regulate oxidative enzymes. This work successfully established a biotransformation method for the efficient transformation of formononetin to produce high-value formononetin derivatives., Competing Interests: Declaration of Competing Interest The authors declared that they have no conflicts of interest to this work. We declare that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Bacillus sp. TTMP20 has high tetramethylpyrazine (TTMP) yield. However, the mechanism of TTMP production in this strain is unclear at present, which limits the modification for strain TTMP20. In this study, key metabolic pathways related to TTMP synthesis were identified, which included glycolytic pathway, tricarboxylic acid cycle and nitrogen metabolism pathway. Moreover, transgenic Bacillus sp. TTMP20 with recombinant vector PHY-300PLK-BDH was constructed. 2,3-butanediol dehydrogenase gene (BDH) overexpression considerably reduced TTMP biosynthesis. This study will supply new insight into the regulation of TTMP biosynthesis at key enzyme gene level., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no competing interests. Ethical Approval: The study has been conducted under the national regulations. The name of the body is given ethical approval., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The efficient treatment of phenol wastewater is of great necessity since it induces serious pollution of water and soil ecosystems. Using biochar-immobilized functional microorganisms can innovatively and sustainably deal with the existing problem. In this study, we utilized response surface methodology (RSM) combined with life cycle assessment (LCA) to improve phenol biodegradation rate through a novel separated alkali-resistant and thermophilic strain Bacillus halotolerans ACY. Bioinformatic analysis revealed the genetic foundation of ACY to adapt to harsh environments. The characteristics of pig manure biochar (PMB) produced at varying pyrolysis temperatures (300-700 ℃) and adsorption experiment were investigated, immobilization of the phenol-degrading ACY on PMB600 under alkaline and high pollution load promoted phenol removal and extreme environment resistance, and the phenol removal rate reached 99.5 % in 7d in actual phenol wastewater, which increased compared with those achieved by PMB (50.6 %) and free bacteria (80.5 %) alone. Scanning Electron Microscope (SEM) and Fourier transform infrared spectrometry (FTIR) observations indicated the successful bacterial immobilization on PMB600. Reusability and economic cost study further demonstrated PMB600 as an excellent carrier for wastewater treatment. LC-MS, toxicology and carbon footprint analyses demonstrated that bacterial metabolism exerted synergy with adsorption for phenol removal, while biodegradation exerted the predominant impact on the immobilized bacterial system. This study provides an eco-friendly and effective approach to treat phenol wastewater., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Novel antimicrobials are urgently needed to combat methicillin-resistant Staphylococcus aureus (MRSA) infections. This study explores the potential of biosurfactants derived from Bacillus rugosus HH2 as a novel antibacterial agent against MRSA. The biosurfactant, identified as surfactin, demonstrated surface-active properties, reducing surface tension to 37.63 mN/m and lowering contact angles in a concentration-dependent manner. It remained stable across a wide range of pH (4-10), temperatures (30-80 °C), and salinity levels (3-18 %). The biosurfactant inhibited the growth of both methicillin-sensitive S. aureus and MRSA, with minimum inhibitory concentrations ranging from 128 to 256 μg/mL. Additionally, it showed anti-biofilm activity, preventing biofilm formation and dispersing established biofilms. Field-emission scanning electron microscopy revealed that the biosurfactant disrupted bacterial cell membranes, leading to leakage. Furthermore, it reduced the production of virulence factors in S. aureus, including hemolysin and lipase. Transcriptomic analysis indicated downregulation of genes associated with quorum sensing and cell adhesion in MRSA. Molecular docking studies showed strong interactions between surfactin and key MRSA proteins, underscoring its potential to overcome antibiotic resistance. Biocompatibility was confirmed through in vitro cytotoxicity and in vivo phytotoxicity tests. In summary, this study presents surfactin as a promising novel antibacterial agent against MRSA, providing insights into its mechanisms of action., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Leather industry is traditionally characterized by the use of large amounts of chemical agents, some of which are toxic to human health and the environment. However, during the last years, many efforts have been made with the aim of successfully implement enzymes as agents for different leather production stages. The lipopeptides produced by the Bacillus spp. genus have excellent surfactants and antibacterial properties and may collaborate in the soaking stage of leather processing as well as in leather preservation. Moreover, Bacillus sp. proteases and lipopeptides can be co-produced in one culture medium, saving the production costs. In the present work, a screening of enzymatic activities was performed on 11 strains of the Bacillus sp. genus that have been isolated from samples of an artisan tannery from Salta, Argentina. In particular, the ability of B. amyloliquefaciens B65 to degrade α-type (nails, hair, wool) and β-type (feathers) keratin was demonstrated by scanning electron microscopy (SEM). The co-production of proteases, keratinases, glycosidases, and lipopeptides of this strain was conducted at 37 °C in mineral media supplemented with chicken feathers. In these nutrient-deficient media, the strain secreted amylases, pectinases, proteases, keratinases, and collagenases. A MALDI-TOF study also revealed that the strains secreted homologues of kurstakins, iturins, surfactins, and fengycines lipopeptides families. Therefore, B. amyloliquefaciens B65 presents great industrial potential applications, not only for tanneries but also for other industries such as pharmaceuticals, food, textiles, and detergents, among others., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Conflict of interest: No., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Application of melatonin and lipopeptides (LPs) derived from Bacillus strains is considered an efficient strategy to control plant diseases at both pre and postharvest stages. However, the combined application of melatonin and LPs has not been studied yet. Therefore, the present study presents the synergistic effect of melatonin and LPs produced by Bacillus atrophaeus strain MCM61 against gray mold disease and its impact on quality parameters and vase life of cut roses. The stems of cut roses along with flowers were dipped in the melatonin solution at concentration (0, 0.2, 0.4, 0.6, and 0.8 mM) and the results indicated that the vase life of flowers treated with the melatonin was enhanced compared to control. Melatonin at 0.6 mM concentration showed the highest vase life of cut roses at day 8. Synergistic treatment with melatonin and LPs of B. atrophaeus MCM61 revealed that MDA and H 2 O 2 content showed the highest decrease in cut roses. Similarly, relative water content, total phenol content, GSH content, and defense enzymes i.e., APX, SOD, PPO, POD, and CAT activities were increased in cut roses treated with co-application of B. atrophaeus MCM61 LPs and melatonin compared to single treatments and control treatment. Furthermore, the longevity of cut roses was also improved in flowers treated with a combined application of MCM61 and melatonin compared to other treatments., Competing Interests: Declarations. Conflict of Interest: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)