Bacterial diversity and composition on the rinds of specific melon cultivars and hybrids from across different growing regions in the United States.

The goal of this study was to characterize the bacterial diversity on different melon varieties grown in different regions of the US, and determine the influence that region, rind netting, and variety of melon has on the composition of the melon microbiome. Assessing the bacterial diversity of the microbiome on the melon rind can identify antagonistic and protagonistic bacteria for foodborne pathogens and spoilage organisms to improve melon safety, prolong shelf-life, and/or improve overall plant health. Bacterial community composition of melons (n = 603) grown in seven locations over a four-year period were used for 16S rRNA gene amplicon sequencing and analysis to identify bacterial diversity and constituents. Statistically significant differences in alpha diversity based on the rind netting and growing region (p < 0.01) were found among the melon samples. Principal Coordinate Analysis based on the Bray-Curtis dissimilarity distance matrix found that the melon bacterial communities clustered more by region rather than melon variety (R2 value: 0.09 & R2 value: 0.02 respectively). Taxonomic profiling among the growing regions found Enterobacteriaceae, Bacillaceae, Microbacteriaceae, and Pseudomonadaceae present on the different melon rinds at an abundance of ≥ 0.1%, but no specific core microbiome was found for netted melons. However, a core of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae were found for non-netted melons. The results of this study indicate that bacterial diversity is driven more by the region that the melons were grown in compared to rind netting or melon type. Establishing the foundation for regional differences could improve melon safety, shelf-life, and quality as well as the consumers' health.

Biosynthetic potential of the sediment microbial subcommunities of an unexplored karst ecosystem and its ecological implications.

Microbial communities from various environments have been studied in the quest for new natural products with a broad range of applications in medicine and biotechnology. We employed an enrichment method and genome mining tools to examine the biosynthetic potential of microbial communities in the sediments of a coastal sinkhole within the karst ecosystem of the Yucatán Peninsula, Mexico. Our investigation led to the detection of 203 biosynthetic gene clusters (BGCs) and 55 secondary metabolites (SMs) within 35 high-quality metagenome-assembled genomes (MAGs) derived from these subcommunities. The most abundant types of BGCs were Terpene, Nonribosomal peptide-synthetase, and Type III polyketide synthase. Some of the in silico identified BGCs and SMs have been previously reported to exhibit biological activities against pathogenic bacteria and fungi. Others could play significant roles in the sinkhole ecosystem, such as iron solubilization and osmotic stress protection. Interestingly, 75% of the BGCs showed no sequence homology with bacterial BGCs previously reported in the MiBIG database. This suggests that the microbial communities in this environment could be an untapped source of genes encoding novel specialized compounds. The majority of the BGCs were identified in pathways found in the genus Virgibacillus, followed by Sporosarcina, Siminovitchia, Rhodococcus, and Halomonas. The latter, along with Paraclostridium and Lysinibacillus, had the highest number of identified BGC types. This study offers fresh insights into the potential ecological role of SMs from sediment microbial communities in an unexplored environment, underscoring their value as a source of novel natural products.

The unique biodegradation pathway of benzo[a]pyrene in moderately halophilic Pontibacillus chungwhensis HN14.

Benzo[a]pyrene (BaP), as the typical representative of polycyclic aromatic hydrocarbons (PAHs), is a serious hazard to human health and natural environments. Though the study of microbial degradation of PAHs has persisted for decades, the degradation pathway of BaP is still unclear. Previously, Pontibacillus chungwhensis HN14 was isolated from high salinity environment exhibiting a high BaP degradation ability. Here, based on the intermediates identified, BaP was found to be transformed to 4,5-epoxide-BaP, BaP-trans-4,5-dihydrodiol, 1,2-dihydroxy-phenanthrene, 2-carboxy-1-naphthol, and 4,5-dimethoxybenzo[a]pyrene by the strain HN14. Furthermore, functional genes involved in degradation of BaP were identified using genome and transcriptome data. Heterogeneous co-expression of monooxygenase CYP102(HN14) and epoxide hydrolase EH(HN14) suggested that CYP102(HN14) could transform BaP to 4,5-epoxide-BaP, which was further transformed to BaP-trans-4,5-dihydrodiol by EH(HN14). Moreover, gene cyp102(HN14) knockout was performed using CRISPR/Cas9 gene-editing system which confirmed that CYP102(HN14) play a key role in the initial conversion of BaP. Finally, a novel BaP degradation pathway was constructed in bacteria, which showed BaP could be converted into chrysene, phenanthrene, naphthalene pathways for the first time. These findings enhanced our understanding of microbial degradation process for BaP and suggested the potential of using P. chungwhensis HN14 for bioremediation in PAH-contaminated environments.

Microbial-based metabolites associated with degradation of imidacloprid and its impact on stress-responsive proteins.

Imidacloprid (IMD), a neonicotinoid insecticide, is intensively used in agricultural fields for effective protection against aphids, cane beetles, thrips, stink bugs, locusts, etc., is causing serious environmental concerns. In recent years, seed treatment with Imidacloprid is being practiced mainly to prevent sucking insect pests. In India, due to the increase in application of this insecticide residue has been proven to have an impact on the quality of soil and water. In view of this, the current investigation is focussed on sustainable approach to minimize the residual effect of IMD in agricultural fields. The present study reveals a most promising imidacloprid resistant bacterium Lysinibacillus fusiformis IMD-Bio5 strain isolated from insecticide-contaminated soil. The isolated bacterial strain upon tested for its biodegradation potential on mineral salt medium (MSM) showed a significant survival growth at 150 g/L of IMD achieved after 3 days, whereas immobilized cells on MSM amended with 200 g/L of IMD as the sole carbon source provided degradation of 188 and 180 g/L of IMD in silica beads and sponge matrices, respectively. The liquid chromatography mass spectrometry was performed to test the metabolite responsive for IMD biodegradation potential of L. fusiformis IMD-Bio5 which showed the induced activity of the metabolite 6-Chloronicotinic acid. Furthermore, as compared to the untreated control, the Lysinibacillus fusiformis IMD-Bio5 protein profile revealed a range of patterns showing the expression of stress enzymes. Thus, results provided a most effective bacterium enabling the removal of IMD-like hazardous contaminants from the environment, which contributes to better agricultural production and soil quality, while long-term environmental advantages are restored.

Exploration of culturable bacterial associates of aphids and their interactions with entomopathogens.

Aphids shelter several bacteria that benefit them in various ways. The associates having an obligatory relationship are non-culturable, while a few of facultative associates are culturable in insect cell lines, axenic media or standard microbiology media. In the present investigation, isolation, and characterization of the culturable bacterial associates of various aphid species, viz., Rhopalosiphum maidis, Rhopalosiphum padi, Sitobion avenae, Schizaphis graminum, and Lipaphis erysimi pseudobrassicae were carried out. A total of 42 isolates were isolated using different growth media, followed by their morphological, biochemical, and molecular characterization. The isolated culturable bacterial associates were found to belong to the genera Acinetobacter, Bacillus, Brevundimonas, Cytobacillus, Fictibacillus, Planococcus, Priestia, Pseudomonas, Staphylococcus, Sutcliffiella, and Tumebacillus which were grouped under seven families of four different orders of phyla Bacillota (Firmicutes) and Pseudomonata (Proteobacteria). Symbiont-entomopathogen interaction study was also conducted, in which the quantification of colony forming units of culturable bacterial associates of entomopathogenic fungal-treated aphids led us to the assumption that the bacterial load in aphid body can be altered by the application of entomopathogens. Whereas, the mycelial growth of entomopathogens Akanthomyces lecanii and Metarhizium anisopliae was found uninhibited by the bacterial associates obtained from Sitobion avenae and Rhopalosiphum padi. Analyzing persistent aphid microflora and their interactions with entomopathogens enhances our understanding of aphid resistance. It also fosters the development of innovative solutions for agricultural pest management, highlighting the intricate dynamics of symbiotic relationships in pest management strategies.

Production and characterization of polyhydroxybutyrate bioplastic precursor from Parageobacillus toebii using low-cost substrates and its potential antiviral activity.

There is an increasing desire for bioplastics produced from renewable resources as an alternative to their petrochemical counterparts. These biopolymers have long-unnoticed antiviral properties. This study aimed to produce and characterize bioplastics by Parageobacillus toebii using low-cost substrates and determine their antiviral activity against coxsackievirus B4. Seven low-cost substrates (bagasse, water hyacinth, rice straw, rice water, sesame husks, molasses, and corn syrup) were compared with glucose for bioplastic precursor production. The highest bioplastic produced was from water hyacinth and glucose, followed by molasses, rice straw, rice water, sesame husks, and bagasse. Water hyacinth and glucose media were further optimized to increase the bioplastic precursor yield. The optimization of the media leads to increases in bioplastic precursor yields of 1.8-fold (3.456 g/L) and 1.496-fold (2.768 g/L), respectively. These bioplastics were further characterized by thermogravimetric analysis (TGA), Fourier-transformed infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR), and gas chromatography-mass spectrometry (GC-MS). They are thermostable, and their characterizations confirm the presence of polyhydroxybutyrate. The antiviral assay showed reasonable antiviral effects for bioplastics from water hyacinth (80.33 %) and glucose (55.47 %) media at 250 µg/mL maximum non-toxic concentrations (MNTC). The present investigation demonstrates a low-cost model for producing polyhydroxybutyrate bioplastic precursor for antiviral applications.

Dynamics of microbial functional guilds involved in the humification process during aerobic composting of chicken manure on an industrial scale.

Proper composting treatment of poultry manure waste is recommended before its use as a fertilizer. This involves many bioprocesses driven by microorganisms. Therefore, it is important to understand microbial mechanisms behind these bioprocesses in manure composting systems. Many efforts have been made to study the microbial community structure and diversity in these systems using high-throughput sequencing techniques. However, the dynamics of microbial interaction and functionality, especially for key microbial functional guilds, are not yet fully understood. To address these knowledge gaps, we collected samples from a 150-day industrial chicken manure composting system and performed the microbial network analysis based on the sequencing data. We found that the family Bacillaceae and genus Bacillus might play important roles in organic matter biodegradation at the mesophilic/thermophilic phases. Genera Virgibacillus, Gracilibacillus, Nocardiopsis, Novibacillus, and Bacillaceae_BM62 were identified as the key ones for humic acid synthesis at the mature phases. These findings improve our understanding about the fundamental mechanisms behind manure composting and can aid the development of microbial agents to promote manure composting performance.

Efficient bio-remediation of multiple aromatic hydrocarbons using different types of thermotolerant, ring-cleaving dioxygenases derived from Aeribacillus pallidus HB-1.

As toxic contaminants, aromatic compounds are widespread in most environmental matrices, and bioenzymatic catalysis plays a critical role in the degradation of xenobiotics. Here, a thermophillic aromatic hydrocarbon degrader Aeribacillus pallidus HB-1 was found. Bioinformatic analysis of the HB-1 genome revealed two ring-cleaving extradiol dioxygenases (EDOs), among which, EDO-0418 was assigned to a new subfamily of type I.1 EDOs and exhibited a broad substrate specificity, particularly towards biarylic substrate. Both EDOs exhibited optimal activities at elevated temperatures (55 and 65 °C, respectively) and showed remarkable thermostability, pH stability, metal ion resistance and tolerance to chemical reagents. Most importantly, simulated wastewater bioreactor experiments demonstrated efficient and uniform degradation performance of mixed aromatic substrates under harsh environments by the two enzymes combined for potential industrial applications. The unveiling of two thermostable dioxygenases with broad substrate specificities and stress tolerance provides a novel approach for highly efficient environmental bioremediation using composite enzyme systems.

Short communication: Investigating optimal laboratory growth conditions of Gracilibacillus halotolerans in media supplemented with salt.

Gracilibacillus halotolerans, a new and relatively unstudied extremophile, extracted from the Great Salt Lake USA, survives in an extreme saline environment. Uncovering optimal laboratory growth conditions can be useful to improve treatment strategies against antibiotic resistance and biofilm formation. In the current study, G. halotolerans growth optimization was tested to determine the ideal saline concentration. In addition, a variety of G. halotolerans'-derived survival strategies were reviewed. The major findings of the current study includes the optimal laboratory growth condition for G. halotolerans that requires the supplement of 5% NaCl. In addition, optimal growth was observed up to 72 h in Luria Bertani (LB) broth. Identifying the optimal laboratory growth conditions for G. halotolerans will standardize growth methods, reduce laboratory cost, and can improve future investigations of extremophile bacteria as model organisms to combat antibiotic resistance, biofilm, and other persister cell characteristics that negatively affect research and clinical settings.

Characterization of a Thermostable Endolysin of the Aeribacillus Phage AeriP45 as a Potential Staphylococcus Biofilm-Removing Agent.

Multidrug-resistant Gram-positive bacteria, including bacteria from the genus Staphylococcus, are currently a challenge for medicine. Therefore, the development of new antimicrobials is required. Promising candidates for new antistaphylococcal drugs are phage endolysins, including endolysins from thermophilic phages against other Gram-positive bacteria. In this study, the recombinant endolysin LysAP45 from the thermophilic Aeribacillus phage AP45 was obtained and characterized. The recombinant endolysin LysAP45 was produced in Escherichia coli M15 cells. It was shown that LysAP45 is able to hydrolyze staphylococcal peptidoglycans from five species and eleven strains. Thermostability tests showed that LysAP45 retained its hydrolytic activity after incubation at 80 °C for at least 30 min. The enzymatically active domain of the recombinant endolysin LysAP45 completely disrupted biofilms formed by multidrug-resistant S. aureus, S. haemolyticus, and S. epidermidis. The results suggested that LysAP45 is a novel thermostable antimicrobial agent capable of destroying biofilms formed by various species of multidrug-resistant Staphylococcus. An unusual putative cell-binding domain was found at the C-terminus of LysAP45. No domains with similar sequences were found among the described endolysins.

Uranium removal in groundwater by Priestia sp. isolated from uranium-contaminated mining soil.

Priestia sp. WW1 was isolated from a uranium-contaminated mining soil and identified. The uranium removal characteristics and mechanism of Priestia sp. WW1 were investigated. The results showed that the removal efficiency of uranium decreased with the increase of initial uranium concentration. When the uranium initial concentration was 5 mg/L, the uranium removal efficiency achieved 92.1%. The increase of temperature could promote the uranium removal. Carbon source could affect the removal rate of uranium, which was the fastest when the methanol was used as carbon source. The solution pH had significant effect on the uranium removal efficiency, which reached the maximum under solution pH 5.0. The experimental results and FTIR as well as XPS demonstrated that Priestia sp. WW1 could remove uranium via both adsorption and reduction. The common chloride ions, sulfate ions, Mn(II) and Cu(II) enhanced the uranium removal, while Fe(III) depressed the uranium removal. The Priestia sp. WW1 could effectively remove the uranium in the actual mining groundwater, and the increase of initial biomass could improve the removal efficiency of uranium in the actual mining groundwater. This study provided a promising bacterium for uranium remediation in the groundwater.

Molecular Cloning, Characterization, and Application of Organic Solvent-Stable and Detergent-Compatible Thermostable Alkaline Protease from Geobacillus thermoglucosidasius SKF4.

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80°C. In addition, the enzyme showed a half-life of 15 h at 80°C, and there was a 60% increase in its activity at 10 mM Ca2+ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

Airborne microorganisms and key environmental factors shaping their community patterns in the core production area of the Maotai-flavor Baijiu.

Airborne microorganisms are important parts of the Moutai-flavor Baijiu brewing microbial community, which directly affects the quality of Baijiu. However, environmental factors usually shape airborne microbiomes in different distilleries, even in the different production areas of the same distillery. Unfortunately, current understanding of environmental factors shaping airborne microbiomes in distilleries is very limited. To bridge this gap, we compared airborne microbiomes in the Moutai-flavor Baijiu core production areas of different distilleries in the Chishui River Basin and systematically investigated the key environmental factors that shape the airborne microbiomes. The top abundant bacterial communities are mainly affiliated to the phyla Actinobacteriota, Firmicutes, and Proteobacteri, whereas Ascomycota and Basidiomycota are the predominant fungal communities. The Random Forest analysis indicated that the biomarkers in three distilleries are Saccharomonospora and Bacillus, Thermoactinomyces, Oceanobacillus, and Methylobacterium, which are the core functional flora contributing to the production of Daqu. The correlation and network analyses showed that the distillery age and environmental temperature have a strong regulatory effect on airborne microbiomes, suggesting that the fermentation environment has a domesticating effect on air microbiomes. Our findings will greatly help us understand the relationship between airborne microbiomes and environmental factors in distilleries and support the production of the high-quality Moutai-flavor Baijiu.

Metabolic engineering of Geobacillus thermoglucosidasius for polymer-grade lactic acid production at high temperature.

The production and application of biodegradable polylactic acid are still severely hindered by the cost of its polymer-grade lactic acid monomers. High-temperature biomanufacturing has emerged as an increasingly attractive approach to enable low-cost and high-efficiency bulk chemical production. In this study, thermophilic Geobacillus thermoglucosidasius was reprogrammed to obtain optically pure l-lactic acid- and d-lactic acid-producing strains, G. thermoglucosidasius GTD17 and GTD7, by using rational metabolic engineering strategies including pathway construction, by-product elimination, and production enhancing. Moreover, semi-rational adaptive evolution was carried out to further improve their lactic acid synthesis performance. The final strains GTD17-55 and GTD7-144 produce 151.1 g/L of l-lactic acid and 153.1 g/L of d-lactic acid at 60 °C, respectively. In consideration of the high temperature, productive performance of these strains is superior compared to the state-of-the-art industrial strains. This study lays the foundation for the low-cost and efficient production of biodegradable plastic polylactic acid.

Genes encoding a novel thermostable bacteriocin in the thermophilic bacterium Aeribacillus pallidus PI8.

AIM: Aeribacillus pallidus PI8 is a Gram-positive thermophilic bacterium that produces thermostable antimicrobial substances against several bacterial species, including Geobacillus kaustophilus HTA426. In the present study, we sought to identify genes of PI8 with antibacterial activity. METHODS AND RESULTS: We isolated, cloned, and characterized a thermostable bacteriocin from A. pallidus PI8 and named it pallidocyclin. Mass spectrometric analyses of pallidocyclin revealed that it had a circular peptide structure, and its precursor was encoded by pcynA in the PI8 genome. pcynA is the second gene within the pcynBACDEF operon. Expression of the full-length pcynBACDEF operon in Bacillus subtilis produced intact pallidocyclin, whereas expression of pcynF in G. kaustophilus HTA426 conferred resistance to pallidocyclin. CONCLUSION: Aeribacillus pallidus PI8 possesses the pcynBACDEF operon to produce pallidocyclin. pcynA encodes the pallidocyclin precursor, and pcynF acts as an antagonist of pallidocyclin.

Endophytic Alkalotolerant Plant Growth-Promoting Bacteria Render Maize (Zea mays L.) Growth Under Alkaline Stress.

This study investigates the role of bacterial endophytes from extreme alkaline environments in alleviating alkaline stress and plant development. Stressful environmental factors, such as soil acidity and alkalinity/sodicity, frequently affect plant development. In the present study, alkaline-tolerant endophytic strains were isolated from three plant species Saccharum munja, Calotropis procera, and Chenopodium album, and 15 out of the total of 48 isolates were selected for further examination of their abiotic stress tolerance. Molecular analysis based on 16S rRNA gene sequencing revealed strains from Enterobacter, Acinetobacter, Stenotrophomonas, Bacillus, Lysinibacillus, and Mammaliicoccus genera. Out of 15 isolates based on their quantitative PGP traits and abiotic stress tolerance, 6 were finally selected for greenhouse experiments. Under alkaline conditions, results demonstrated that the strains from the genera Enterobacter, Bacillus, Stenotrophomonas, and Lysinibacillus had beneficial effects on maize growth. These findings suggest that using a combination of bacteria with multiple plant growth-promoting attributes could be a sustainable approach to enhance agricultural yield, even in a challenging alkaline environment. The study concludes that the application of bacterial endophytes from plants growing in extremely alkaline environments might provide other plants with similar stress-tolerance abilities. The outcome of the study provides a basis for future exploration of the mechanisms underlying endophyte-induced stress tolerance.

Ancient Roman bacterium against current issues: strain Aquil_B6, Paenisporosarcina quisquiliarum, or Psychrobacillus psychrodurans?

IMPORTANCE: Since 1988, through the United States government's founding, the National Center for Biotechnology Information (NCBI) has provided an invaluable service to scientific advancement. The universality and total freedom of use if on the one hand allow the use of this database on a global level by all researchers for their valuable work, on the other hand, it has the disadvantage of making it difficult to check the correctness of all the materials present. It is, therefore, of fundamental importance for the correctness and ethics of research to improve the databases at our disposal, identifying and amending the critical issues. This work aims to provide the scientific community with a new sequence for the type strain Paenisporosarcina quisquiliarum SK 55 and broaden the knowledge of the Psychrobacillus psychrodurans species, in particular, considering the ancient strain Aquil_B6 found in an ancient Roman amphora.

Structure of the Lysinibacillus sphaericus Tpp49Aa1 pesticidal protein elucidated from natural crystals using MHz-SFX.

The Lysinibacillus sphaericus proteins Tpp49Aa1 and Cry48Aa1 can together act as a toxin toward the mosquito Culex quinquefasciatus and have potential use in biocontrol. Given that proteins with sequence homology to the individual proteins can have activity alone against other insect species, the structure of Tpp49Aa1 was solved in order to understand this protein more fully and inform the design of improved biopesticides. Tpp49Aa1 is naturally expressed as a crystalline inclusion within the host bacterium, and MHz serial femtosecond crystallography using the novel nanofocus option at an X-ray free electron laser allowed rapid and high-quality data collection to determine the structure of Tpp49Aa1 at 1.62 Å resolution. This revealed the packing of Tpp49Aa1 within these natural nanocrystals as a homodimer with a large intermolecular interface. Complementary experiments conducted at varied pH also enabled investigation of the early structural events leading up to the dissolution of natural Tpp49Aa1 crystals-a crucial step in its mechanism of action. To better understand the cooperation between the two proteins, assays were performed on a range of different mosquito cell lines using both individual proteins and mixtures of the two. Finally, bioassays demonstrated Tpp49Aa1/Cry48Aa1 susceptibility of Anopheles stephensi, Aedes albopictus, and Culex tarsalis larvae-substantially increasing the potential use of this binary toxin in mosquito control.

Aquibacillus rhizosphaerae sp. nov., an Indole Acetic Acid (IAA)-producing Halotolerant Bacterium Isolated from the Rhizosphere Soil of Kalidium cuspidatum.

A bacterium (named strain LR5S19T) was isolated from the rhizosphere soil of the halophyte Kalidium cuspidatum in Baotou, Inner Mongolia, China. Strain LR5S19T was Gram-stain-positive, motile with a polar flagellum, rod shaped, and spore forming at the terminal position in swollen sporangia, and it grew at 10-40 ℃ (optimum 30 ℃), pH 6.0-9.0 (optimum pH 7.0), and in the presence of 1.0-15.0% (w/v) NaCl (optimum 2.0%). The phylogenetic analysis of the 16S rRNA gene showed that strain LR5S19T shared the highest similarity (96.7%) with A. koreensis JCM 12387T, followed by A. kalidii HU2P27T (96.2%), A. sediminis BH258T (96.1%), and 'A. salsiterrae' 3ASR75-54T (96.0%). The ANIb, AAI and dDDH values between strain LR5S19T and its closely related type strains were 69.3-73.8%, 65.4-72.4% and 19.2-20.3%, respectively. The major polar lipids in strain LR5S19T consisted of diphosphatidylglycerol, phosphatidylglycerol, and three unidentified phospholipids, while MK-7 was the major respiratory quinone. The major fatty acids of the strain were anteiso-C15:0 and iso-C15:0. Based on phylogenomic and phenotypic results, strain LR5S19T should be classified as a novel species within the genus Aquibacillus, for which Aquibacillus rhizosphaerae sp. nov. is proposed. The type strain is LR5S19T (= CGMCC 1.62028T = KCTC 43434T). The comparative genomic analysis revealed that all eight members of Aquibacillus could utilize D-glucose via the glycolysis-gluconeogenesis pathway or the pentose phosphate pathway and use the tricarboxylic acid cycle as the metabolic center. The potassium ion transport proteins and compatible solute synthesis pathways in all the members likely also help them cope with hypersaline environments.

Bacteria intrinsic to Medicago sativa (alfalfa) reduce Salmonella enterica growth in planta.

AIMS: The purpose of this study was to determine whether plant-associated bacteria (PAB) can reduce Salmonella enterica colonization and infection of alfalfa sprouts to reduce the risk of foodborne illness. METHODS: We isolated PAB from alfalfa seeds and sprouts. Monoclonal isolates of the bacteria were obtained and tested for their ability to inhibit Salmonella Typhimurium growth in alfalfa sprouts over 6 days. Genome sequencing and annotation were used to construct draft genomes of the bacteria isolated in this study using Illumina sequencing platform. RESULTS: We observed that a cocktail of five PAB could reduce Salmonella growth in alfalfa sprouts from ∼108 to ∼105 CFU g-1, demonstrating a protective role. Genome sequencing revealed that these bacteria were members of the Pseudomonas, Pantoea, and Priestia genus, and did not possess genes that were pathogenic to plants or animals. CONCLUSIONS: This work demonstrates that PAB can be utilized to reduce pathogen levels in fresh produce, which may be synergistic with other technologies to improve the safety of sprouts and other fresh produce.