mBio® An ASM Access® Publication

The global regulator LaeA is widely recognized as a master activator of secondary metabolism and development in filamentous fungi. Yet its role under genetically buffered or metabolically stable conditions-where canonical phenotypes are masked-remains poorly understood. This study aimed to characterize the LaeA ortholog (ThlaeA) in Trichoderma hypoxylon and to elucidate its regulatory role in a ΔThtri5 background, where trichodiene synthase function is disrupted. We constructed single and double...

The post-translational lipoprotein modification pathway is conserved in bacteria, in which prolipoprotein phosphatidylglycerol diacylglyceryl transferase (Lgt) catalyzes the first and committed step. Due to its essentiality for cell viability in Proteobacteria, its membrane localization, and relative accessibility, Lgt is proposed as a promising target for the development of novel antibiotics. To answer the question of the degree of conservation between Lgt homologs of WHO-listed pathogenic...

Inorganic polyphosphate (polyP) is a linear polymer composed of three to several hundred orthophosphate units linked by high-energy phosphoanhydride bonds and is found in both prokaryotes and eukaryotes. In Trypanosoma cruzi, the causative agent of Chagas disease, polyP plays important roles in osmoregulation and persistence within host tissues and is synthesized by a polyP polymerase known as the vacuolar transporter chaperone (VTC) complex. This complex, localized to acidocalcisomes, is...

Biofilms are structured microbial communities that thrive on diverse surfaces in natural, industrial, and host environments. The biofilm lifestyle underpins microbial survival, shapes ecosystem function, and drives persistent infections; yet, for many microbes, the molecular determinants of biofilm development remain poorly defined. Here, we introduce "label-free analysis of biofilms" (LFAB), an imaging method that integrates time-lapse, low-magnification brightfield microscopy with regional...

DNA phosphorothioate (PT) modification is an epigenetic mark that enables bacteria to discriminate self from non-self DNA, directing restriction effectors to cleave unmodified foreign DNA. In the PT-dependent Ssp system, SspE acts as the restriction effector that recognizes PT marks to block phage propagation. While the mechanism of the Streptomyces homolog (StSspE) is known, the basis for the exceptional potency of Escherichia coli (E. coli) 3234/A SspE (EcSspE) remained unclear. Here, we...

Aim2-like receptors (ALRs) play crucial roles in innate immune signaling pathways and demonstrate strong positive selection likely driven by pathogens. IFI207, an ALR found in all Mus species, enhances interaction with and stabilization of STING, contributing to the control of murine leukemia virus (MLV) infection. We show here that IFI207 enhances the type 1 interferon response by inhibiting activation-induced K63-linked ubiquitination of STING, thereby preventing its recognition by hepatocyte...

The cell-to-cell communication process called quorum sensing enables bacteria to synchronize collective behaviors. Quorum sensing relies on the production, release, and detection of signaling molecules called autoinducers. In Vibrio cholerae, the VqmA transcription factor, following binding of the DPO autoinducer, activates the expression of the gene encoding the VqmR small regulatory RNA. VqmR controls traits including biofilm formation. Here, we identify repressors of DPO-VqmA-VqmR signaling....

Rhizobia live as free-living microorganisms in the soil and in association with legume hosts. Both environments exert selective pressures on rhizobia, influencing the reproductive success of individual strains (e.g., fitness). The soil, a heterogeneous and fluctuating environment, is often overlooked, and little is known about whether selection in the soil influences the outcomes of the rhizobium-legume mutualism. We exposed a mixture of 68 Sinorhizobium meliloti strains to soil-mediated...

Klebsiella pneumoniae is a leading cause of global deaths due to antibiotic resistance. Of particular concern is the rapid expansion of resistance to beta-lactam antibiotics within K. pneumoniae lineages. The environmental factors that influence pathogen physiology and, subsequently, antibiotic resistance remain poorly understood. Here, we demonstrate that physiologically relevant reductions in pH increased K. pneumoniae beta-lactam resistance as much as 64-fold, with the most dramatic increase...

The atmosphere contains thousands to millions of bacterial cells per cubic meter. However, it remains unclear if microbes are at all active or growing in situ or whether they are merely being transported in an inactive state. Based on the analyses of 32 overland radiation fog events over a 2-year period, we show that fog waters, with bacterial concentrations similar to those in continental or marine bodies of water, contain microbiomes well differentiated in composition from those in the dry...

Since the COVID-19 pandemic, several reverse genetics platforms for SARS-CoV-2 have been established. In general, a plasmid-based reverse genetics system is stable and easy to manipulate, distribute, and store. However, traditional methods for the assembly of a large viral genome in a plasmid rely on natural and artificially engineered restriction sites, which are inefficient, time-consuming, labor-intensive, and frequently not successful. Here, we developed a yeast-based homologous...

Showing the data is the first rule of effective figures, yet this mandate is often ignored. Perhaps the signature offender is the "dynamite plot"-a bar graph showing mean and error. Here, we evaluate recent trends in the use of dynamite plots by analyzing 8,834 figures from 2,930 studies published between 2021 and 2025 in 18 journals from five fields of biology. We find that dynamite plots constitute ~25% of figures and are especially common in microbiology journals. However, the use of dynamite...

Bacteria produce high-affinity, iron-chelating secondary metabolites called siderophores to access insoluble Fe(III) in their environments. Genome mining has revealed many predicted siderophore biosynthetic gene clusters (BGCs) in bacterial genomes; however, the structures of their siderophore products remain mostly undetermined. This limits our molecular-level understanding of how bacteria acquire iron. Here, we apply inverse stable isotope labeling (InverSIL) to rapidly connect predicted...

In fungi, the continuous biosynthesis and remodeling of the cell wall are crucial for growth, division, and development. A hallmark of fungal cell walls is their layered structure, which includes several carbohydrate polymers, such as β-glucans, and a large number of associated cell wall proteins. The fungal-specific family of SUN domain proteins has been implicated in cell wall remodeling and cell separation, but detailed structure-based analyses revealing precise molecular functions have been...

Bacteroides spp. are a key immune-programming microbe in healthy individuals-these bacteria have been shown to be reduced in abundance across a variety of disease states. Our study investigated the systemic and region-specific responses to Bacteroides colonization in the gut, including sex-related differences, in mice. Utilizing C57BL/6 mice, we administered Bacteroides to conventional, antibiotic-treated mice, then assessed this microbe's influence on the gut microbiota composition and...