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le of degrading nicotine. The T6SS in strain JY-Q is able to deliver TseN to kill competitors and provide a growth advantage by a contact-independent pattern. selleck kinase inhibitor TseN could monitor the intracellular NAD+ level by its hydrolase activity, causing cytotoxicity in competitive rivals but metabolic homeostasis on JY-Q. Moreover, JY-Q could be protected from TseN toxicity by the immunity protein TsiN. In conclusion, we found that TseN with cytotoxicity to bacterial competitors facilitated the nicotine tolerance of JY-Q. We therefore reveal a working model between T6SS and nicotine metabolism. This finding indicates that multiple diversified weapons have been evolved by bacteria for their growth and robustness.Biosurfactant production is a common trait in leaf surface-colonizing bacteria that has been associated with increased survival and movement on leaves. At the same time, the ability to degrade aliphatics is common in biosurfactant-producing leaf colonizers. Pseudomonads are common leaf colonizers and have been recognized for their ability to produce biosurfactants and degrade aliphatic compounds. In this study, we investigated the role of biosurfactants in four non-plant-pathogenic Pseudomonas strains by performing a series of experiments to characterize their surfactant properties and their role during leaf colonization and diesel degradation. The biosurfactants produced were identified using mass spectrometry. Two strains produced viscosin-like biosurfactants, and the other two produced massetolide A-like biosurfactants, which aligned with the phylogenetic relatedness between the strains. To further investigate the role of surfactant production, random Tn5 transposon mutagenesis was performed to generate knroduction on leaf colonization, and we demonstrate that the lack of surfactant production decreases the ability to degrade aliphatic compounds. This indicates that leaf surface-dwelling, surfactant-producing bacteria contribute to degradation of environmental hydrocarbons and may be able to utilize leaf surface waxes. This has implications for plant-microbe interactions and future studies.Diseases caused by soilborne fungal pathogens result in significant crop yield losses and quality reduction. Streptomyces albidoflavus strain W68 is effective in controlling several soilborne fungal diseases. To identify antifungal substances critical for biocontrol activity of W68, the genome of W68 was sequenced and a linear chromosome of 6.80 Mb was assembled. A total of 21 secondary metabolite biosynthesis gene clusters (BGCs), accounting for 12.27% of the genome, were identified. Core gene deletion mutants for each of all 8 BGCs for nonribosomal peptide synthetases and polyketide synthases were created. Among them, only the mutant lacking ctg1-5755 (the gene was renamed as fscD W68) in BGC 19, which shares 100% sequence similarity with the BGC for candicidin synthesis, showed obvious reduction in antifungal activity. A pot experiment revealed that biocontrol effects of the ΔfscD W68 mutant in Rhizoctonia rot of cucumber were also significantly compromised relative to W68. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed that W68 but not the ΔfscD W68 mutant can produce candicidin isomers, indicating that the production of candicidin isomers is key for antifungal activity and biocontrol activity of S. albidoflavus W68.IMPORTANCE This study reports that candicidin-like secondary metabolites produced by microbial cells in natural soil environments can effectively control soilborne fungal diseases, revealing a novel mechanism of microbial biocontrol agents. We demonstrated that the main antifungal activity and biocontrol activity of Streptomyces albidoflavus strain W68 are attributable to the production of candicidin isomers, suggesting that gene clusters for candicidin-like compound biosynthesis might be used as molecular markers to screen and breed microbial strains for biocontrol agent development.Due to their unique metabolism and important ecological roles, deep-sea hydrothermal archaea have attracted great scientific interest. Among these archaea, DPANN superphylum archaea are widely distributed in hydrothermal vent environments. However, DPANN metabolism and ecology remain largely unknown. In this study, we assembled 20 DPANN genomes among 43 reconstructed genomes obtained from deep-sea hydrothermal vent sediments. Phylogenetic analysis suggests 6 phyla, comprised of Aenigmarchaeota, Diapherotrites, Nanoarchaeota, Pacearchaeota, Woesearchaeota, and a new candidate phylum we have designated Kexuearchaeota These are included in the 20 DPANN archaeal members, indicating their broad diversity in this special environment. Analyses of their metabolism reveal deficiencies due to their reduced genome size, including gluconeogenesis and de novo nucleotide and amino acid biosynthesis. However, DPANN archaea possess alternate strategies to address these deficiencies. DPANN archaea also have the potential to assimilate nitrogen and sulfur compounds, indicating an important ecological role in the hydrothermal vent system.IMPORTANCE DPANN archaea show high distribution in the hydrothermal system, although they display small genome size and some incomplete biological processes. Exploring their metabolism is helpful to understand how such small forms of life adapt to this unique environment and what ecological roles they play. In this study, we obtained 20 high-quality metagenome-assembled genomes (MAGs) corresponding to 6 phyla of the DPANN group (Aenigmarchaeota, Diapherotrites, Nanoarchaeota, Pacearchaeota, Woesearchaeota, and a new candidate phylum designated Kexuearchaeota). Further metagenomic analyses provided insights on the metabolism and ecological functions of DPANN archaea to adapt to deep-sea hydrothermal environments. Our study contributes to a deeper understanding of their special lifestyles and should provide clues to cultivate this important archaeal group in the future.The 2014 caramel apple listeriosis outbreak was traced back to cross-contamination between food contact surfaces (FCS) of equipment used for packing and fresh apples. For Washington state, the leading apple producer in the United States with 79% of its total production directed to the fresh market, managing the risk of apple contamination with Listeria monocytogenes within the packing environment is crucial. The objectives of this study were to determine the prevalence of Listeria spp. on FCS in Washington state apple packinghouses over two packing seasons and to identify those FCS types with the greatest likelihood to harbor Listeria spp. Five commercial apple packinghouses were visited quarterly over two consecutive year-long packing seasons. A range of 27 to 50 FCS were swabbed at each facility to detect Listeria spp. at two sample times, (i) postsanitation and (ii) in-process (3 h of packinghouse operation), following a modified protocol of the FDA's Bacteriological Analytical Manual method. Among 2,988 samples tested, 4.