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n antimicrobial peptides and increased hemolytic activity. In addition, SAN2 showed increased lethal activity in a mouse bacteremia model. Our study provides new insights that the acquisition of resistance against food preservatives may modulate virulence in S. aureus, suggesting that we need to pay more attention to the use of food preservatives together with antibiotics. Copyright © 2020 American Society for Microbiology.The quinolone ring is a common core structure of natural products exhibiting antimicrobial, cytotoxic, and signaling activities. A prominent example is the Pseudomonas quinolone signal (PQS), a quorum sensing signal molecule involved in the regulation of virulence of P. aeruginosa The key reaction to quinolone inactivation and biodegradation is the cleavage of the 3-hydroxy-4(1H)-quinolone ring, catalyzed by dioxygenases (HQDs) which are members of the α/β-hydrolase fold superfamily. The α/β-hydrolase fold core domain consists of a β-sheet surrounded by α-helices, with an active site usually containing a catalytic triad comprising a nucleophilic residue, an acidic residue, and a histidine. The nucleophile is located at the tip of a sharp turn called the "nucleophilic elbow". In this work, we developed a search workflow for the identification of HQD proteins from databases. Search and validation criteria include a [H-x(2)-W] motif at the nucleophilic elbow, a [HFP-x(4)-P] motif comprising the catalytic histidie defined search and validation criteria for the primarily motif-based identification of 3-hydroxy-4(1H)-quinolone 2,4-dioxygenases (HQD). HQDs are key enzymes for the inactivation of metabolites which can have signaling, antimicrobial, or cytotoxic functions. The HQD candidates detected in this study occur particularly in environmental and plant-associated microorganisms. Because HQDs active towards the Pseudomonas quinolone signal (PQS) likely contribute to interactions within microbial communities and modulate the virulence of Pseudomonas aeruginosa, we analyzed the catalytic properties of a PQS-cleaving subset of HQDs, and specified characteristics to identify PQS-cleaving dioxygenases within the HQD family. Copyright © 2020 American Society for Microbiology.Biological hydrolysis of cellulose above 70°C involves microorganisms that secrete free enzymes, and deploy separate protein systems to adhere to their substrate. Strongly cellulolytic Caldicellulosiruptor bescii is one such extreme thermophile, which deploys modular, multi-functional carbohydrate acting enzymes to deconstruct plant biomass. Additionally, C. bescii also encodes for non-catalytic carbohydrate binding proteins, which likely evolved as a mechanism to compete against other heterotrophs in carbon limited biotopes that these bacteria inhabit. Analysis of the Caldicellulosiruptor pangenome identified a type IV pilus (T4P) locus encoded upstream of the tāpirins, that is encoded for by all Caldicellulosiruptor species. check details In this study, we sought to determine if the C. bescii T4P plays a role in attachment to plant polysaccharides. The major C. bescii pilin (CbPilA) was identified by the presence of pilin-like protein domains, paired with transcriptomics and proteomics data. Using immuno-dot blots, we detive genomics analyses identified a T4 pilus locus encoded by an extremely thermophilic genus within the Firmicutes. Here, we demonstrate that attachment to plant biomass-related carbohydrates by strongly cellulolytic Caldicellulosiruptor bescii is mediated by T4 pilins. Surprisingly, xylan but not cellulose induced expression of the major T4 pilin. Regardless, the C. bescii T4 pilin interacts with both polysaccharides at high temperatures, and is located to the cell surface where it is directly involved in C. bescii attachment. Adherence to polysaccharides is likely key to survival in environments where carbon sources are limiting, allowing C. bescii to compete against other plant degrading microorganisms. Copyright © 2020 American Society for Microbiology.Autotoxic ginsenosides have been implicated as one of the major causes for replant failure of Sanqi ginseng (Panax notoginseng), however, the impact of autotoxic ginsenosides on the fungal microbiome, especially on soil-borne fungal pathogens, remain poorly understood. In this study, we aimed to investigate the influence of ginsenoside monomers Rg1, Rb1, Rh1, and their mixture (Mix) on the composition and diversity of the soil fungal community as well as the abundance and growth of soil-borne pathogen Fusarium oxysporum in pure culture. The addition of autotoxic ginsenosides altered the composition of the total fungal microbiome as well as the taxa within the shared and unique treatment-based components, but not α-diversity. In particular, autotoxic ginsenosides enriched potentially pathogenic taxa, such as Alternaria, Cylindrocarpon, Gibberella, Phoma, and Fusarium, and decreased the abundances of beneficial taxa such as Acremonium, Mucor, and Ochroconis Relative abundances of pathogenic taxa were significanminishing arable land resources drive the farmers to employ consecutive monoculture systems. Replant failure has severely threatened the sustainable production of Sanqi ginseng and causes great economic losses annually. Worse still, the acreage and severity of replant failure are yearly increased, that may destroy the Sanqi ginseng industry in the near future. The significance of this work is to decipher the mechanism of how autotoxic ginsenosides promote the accumulation of soil-borne pathogens and disrupt the equilibrium of soil fungal microbiomes. This result may help us to develop effective approaches to successfully conquer the replant failure of Sanqi ginseng. Copyright © 2020 American Society for Microbiology.The homeobox gene family of transcription factors (HTF) control many developmental pathways and physiological processes in eukaryotes. We previously showed that a conserved HTF (FgHtf1) regulates conidia morphology in the plant pathogenic Fusarium graminearum This study investigates the mechanism of FgHtf1-mediated regulation and identifies putative FgHtf1 target genes by chromatin immunoprecipitation assay combined with parallel DNA sequencing (ChIP-seq) and RNA sequencing. A total of 186 potential binding peaks, including 142 genes directly regulated by FgHtf1 were identified. Subsequent motif prediction analysis identified two DNA binding motifs TAAT and CTTGT. Among the FgHtf1 target genes included FgHTF1 itself and several important conidiation related genes (e.g. FgCON7), the chitin synthase pathway genes, and the aurofusarin biosynthetic pathway genes. In addition, FgHtf1 may regulate the cAMP-PKA-Msn2/4 and Ca2+-calcineurin-Crz1 pathways. Taken together, these results suggest that in addition to auto-regulation, FgHtf1 also controls global gene expression, and promotes a shift to aerial growth and conidiation in F.