Biology subjects

U'Ren, J. M.

Publications and source records attributed to U'Ren, J. M..

4 recordsLinked to original sources

bioRxiv2025

Genomic and metagenomic survey of microbial carbonic anhydrase genes reveals novel clades, high diversity, and biome-specificity

Carbonic anhydrase (CA) enzymes catalyze the interconversion of carbon dioxide and bicarbonate with an efficiency exceeded only by superoxide dismutase. CA enzymes have convergently evolved multiple times from phylogenetically distant organisms into structurally unrelated classes (, {beta}, {gamma},{delta} ,{zeta} , , {theta}, {iota}) with conserved physiological functions involved in photosynthesis, respiration, pH homeostasis, CO2 transport, and carbonyl sulfide hydrolysis that play central roles in medicine and the environment. Here, we leverage the recent surge in publicly available genomes and metagenomes to re-examine our understanding of the abundance, diversity, and phylogenetic relationships of the three major CA classes in Bacteria/Archaea and microbial Eukaryotes (Fungi, algae). We recovered a total of 57,218 -, {beta}-, and {gamma}-CA sequences from 24,184 metagenomes and genomes, including the first detection of -CA from an Archaeal species. CA sequences formed 3,859 protein clusters (1,188 with [≥] 3 sequences) that were taxonomically conserved at higher levels (i.e., Superkingdom, Phylum, Class). When viewed within a phylogenetic framework, the majority of subclades contained CAs representing multiple Superkingdoms, although numerous novel {beta}-CA clades appear unique to Fungi. Queries of CA Hidden Markov models (HMMs) against all public meta-genome and -transcriptome datasets revealed that CA is a ubiquitous enzyme present in virtually all sampled environments. However, CA clusters that were taxonomically conserved also appeared environment-specific, generating high CA diversity. This work represents an important contribution to the evolution, diversity, and environmental distribution of an enzyme that is key for life and has broad environmental and industrial applications.

genomics↗

bioRxiv2024

Hyperdiverse, bioactive, and interaction-specific metabolites produced only in co-culture suggest diverse competitors may fuel secondary metabolism of xylarialean fungi

Xylariales is one of the largest and most ecologically diverse fungal orders that is well-known for its chemical diversity. Enhanced secondary metabolism of Xylariales taxa is associated with increased gene duplication and horizontal gene transfer (HGT) of biosynthetic gene clusters (BGCs), especially in generalist taxa with both greater saprotrophic abilities and broader host ranges as foliar endophytic symbionts. Thus, one hypothesis for BGC diversification among more generalist fungi is that diverse competitive interactions--in both their free-living and symbiotic life stages with many hosts--may exert selective pressure for HGT and a diverse metabolic repertoire. Here, we used untargeted metabolomics to examine how competition (pairwise co-cultures) between seven xylarialean fungi influenced their metabolite production. Of the >9,000 total features detected, 6,115 and 2,071 were over-represented in co-cultures vs. monocultures, respectively. For each strain, each additional co-culture interaction resulted in an 11-14-fold increase in metabolite richness compared to monocultures, reflecting the limited amount of metabolite overlap among different co-culture combinations. Phylogenetic relatedness and BGC content did not impact the diversity of metabolites produced in co-culture; however, co-cultures between more ecologically distinct fungi elicited the strongest metabolic response. Overall, the diversity, specificity, and putative bioactivity of metabolites over-represented only in co-culture supports the role of widespread and diverse competitive fungal interactions to drive xylarialean metabolic diversification. Additionally, as fungal-produced plant hormones were only detected in co-culture, our results reveal the potential for in planta interactions among fungal endophytes to influence the host plant. ImportanceSaprotrophic and endophytic xylarialean fungi are among the most prolific producers of bioactive secondary metabolites, with numerous industrial uses as antibiotics, pharmaceuticals, and insecticidal toxins. Fungal secondary metabolites are typically encoded in biosynthetic gene clusters (sets of physically clustered genes), but the products of most clusters are unknown as the genes are not active in typical culture conditions. Co-cultures can help to "turn on" fungal secondary metabolite production, yet factors that can influence co-culture outcomes are largely unknown. Here, we used untargeted metabolomics to assess how differences in genomic content, ecology, and phylogenetic relatedness among seven diverse xylarialean fungal strains impact metabolic production in co-culture. As expected, co-culturing significantly increased metabolite diversity, as well as the abundance of putatively bioactive metabolites. Each new pairwise combination produced different metabolites, indicative of strain-specific responses to competitors. This new information will enable further characterization of the immense biotechnological potential of xylarialean fungi.

microbiology↗

bioRxiv2021

Cyanolichen microbiome contains novel viruses that encode genes to promote microbial metabolism

Lichen thalli are formed through the symbiotic association of a filamentous fungus and photosynthetic green alga and/or cyanobacterium. Recent studies have revealed lichens also host highly diverse communities of secondary fungal and bacterial symbionts, yet few studies have examined the viral component within these complex symbioses. Here, we describe viral biodiversity and functions in cyanolichens collected from across North America and Europe. As current machine learning viral-detection tools are not trained on complex eukaryotic metagenomes, we first developed efficient methods to remove eukaryotic reads prior to viral detection and a custom pipeline to validate viral contigs predicted with three machine-learning methods. Our resulting high-quality viral data illustrate that every cyanolichen thallus contains diverse viruses that are distinct from viruses in other terrestrial ecosystems. In addition to cyanobacteria, predicted viral hosts include other lichen-associated bacterial lineages and algae, although a large fraction of viral contigs had no host prediction. Functional annotation of cyanolichen viral sequences reveals numerous viral-encoded auxiliary metabolic genes (AMGs) involved in amino acid, nucleotide, and carbohydrate metabolism, including AMGs for secondary metabolism (antibiotics and antimicrobials) and fatty acid biosynthesis. Overall, the diversity of cyanolichen AMGs suggests that viruses may alter microbial interactions within these complex symbiotic assemblages.

microbiology↗

bioRxiv2021

Secondary metabolism drives ecological breadth in the Xylariaceae

Global, large-scale surveys of phylogenetically diverse plant and lichen hosts have revealed an extremely high richness of endophytes in the Xylariales, one of the largest clades of filamentous fungi and a significant source of novel secondary metabolites (SMs). Endophytes may produce host protective antimicrobial or insecticidal SMs, as well as compounds that facilitate symbiotic establishment through suppression or degradation of host immune response, but the ecological roles of most SMs are unknown. Here we characterized metabolic gene clusters in 96 genomes of endophytes and closely related saprotrophs and pathogens in two clades of Xylariales (Xylariaceae s.l. and Hypoxylaceae). Hundreds of genes appear horizontally transferred to xylarialean fungi from distantly related fungi and bacteria, including numerous genes in secondary metabolite gene clusters (SMGCs). Although all xylarialean genomes contain hyperabundant SMGCs, we show that increased gene duplications, horizontal gene transfers (HGTs), and SMGC content in Xylariaceae s.l. taxa are linked to greater phylogenetic host breadth, larger biogeographic distributions, and increased capacity for lignocellulose decomposition compared to Hypoxylaceae taxa. Overall, our results suggest that xylarialean endophytes capable of dual ecological modes (symbiotic and saprotrophic) experience greater selection to diversify SMGCs to both increase competitiveness within microbial communities and facilitate diverse symbiotic interactions.

genomics↗