Biology subjects

Gostincar, C.

Publications and source records attributed to Gostincar, C..

3 recordsLinked to original sources

bioRxiv2025

Genomic rearrangements at the MAT locus suggest reproductive shifts in Rhodotorula yeasts

Transitions from canonical outcrossing to rare, cryptic, or noncanonical reproduction are widespread in fungi, but how mating-type (MAT) systems are reorganized at the genomic and population levels during these shifts remains unclear. The coexistence of sexually reproducing species and putatively asexual lineages makes Rhodotorula a natural comparative system for addressing this question. We analyzed 249 globally sampled strains using a combination of long-read and short-read sequencing. Phylogenomics resolved three major clades and several closely related species complexes. Chromosome-scale assemblies confirmed physical separation of the pheromone/receptor (P/R) and homeodomain (HD) loci, whereas non-random P/R-HD associations revealed constrained tetrapolar inheritance. The P/R locus showed conserved synteny within mating types but extensive structural divergence between A1 and A2 alleles, whereas the HD locus remained compact and conserved. Mating-type distributions varied across clades, with both A1 and A2 present in Clade C, lineage-structured partitioning in Clade B, and pronounced A2 dominance in Clade A. Genome-wide linkage disequilibrium (LD) decay in putatively asexual R. mucilaginosa, although slower than in sexual R. diobovata, was consistent with historical recombination in a species without an observed sexual cycle. Clade A further exhibited deep trans-specific polymorphism of STE3.A2 and relaxed purifying selection, mosaic A2 P/R configurations retaining RHA.A1, A1/A2 and A2/A2 hybrid genomes, and A2-associated gene content beyond MAT loci. In conclusion, our findings underscore the dynamic nature of MAT-locus remodeling in Rhodotorula and establish this genus as a valuable model for investigating transitions from heterothallism toward reproductive strategies less dependent on opposite-type partners.

evolutionary biology↗

bioRxiv2021

The termite fungal cultivar Termitomyces combines diverse enzymes and oxidative reactions for plant biomass conversion

Macrotermitine termites have domesticated fungi in the genus Termitomyces as their primary food source using pre-digested plant biomass. To access the full nutritional value of lignin-enriched plant biomass, the termite-fungus symbiosis requires the depolymerization of this complex phenolic polymer. While most previous work suggests that lignocellulose degradation is accomplished predominantly by the fungal cultivar, our current understanding of the underlying biomolecular mechanisms remains rudimentary. Here, we provide conclusive OMICs and activity-based evidence that Termitomyces partially depolymerizes lignocellulose through the combined actions of high-redox potential oxidizing enzymes (laccases, aryl-alcohol oxidases and a manganese peroxidase), the production of extracellular H2O2 and Fenton-based oxidative degradation, which is catalyzed by a newly described 2-methoxybenzoquinone/hydroquinone redox shuttle system and mediated by secreted chelating dicarboxylic acids. In combination, our approaches reveal a comprehensive depiction of how the efficient biomass degradation mechanism in this ancient insect agricultural symbiosis is accomplished through a combination of white- and brown-rot mechanisms. ImportanceFungus-growing termites have perfected the decomposition of recalcitrant plant biomass to access valuable nutrients by engaging in a tripartite symbiosis with complementary contributions from a fungal mutualist and a co-diversified gut microbiome. This complex symbiotic interplay makes them one of the most successful and important decomposers for carbon cycling in Old World ecosystems. To date, most research has focused on the enzymatic contributions of microbial partners to carbohydrate decomposition. Here we provide genomic, transcriptomic and enzymatic evidence that Termitomyces also employs redox mechanisms, including diverse ligninolytic enzymes and a Fenton-based hydroquinone-catalyzed lignin-degradation mechanism, to break down lignin-rich plant material. Insights into these efficient decomposition mechanisms open new sources of efficient ligninolytic agents applicable for energy generation from renewable sources.

microbiology↗

bioRxiv2020

Spider webs as eDNA tool for biodiversity assessment of life's domains

The concept of environmental DNA (eDNA) utilizes nucleic acids of organisms directly from the environment. Recent breakthrough studies have successfully detected a wide spectrum of prokaryotic and eukaryotic eDNA from a variety of environments, ranging from ancient to modern, and from terrestrial to aquatic. These numerous sources promise to establish eDNA as a tool for diverse scientific settings. Here, we propose and establish spider webs as a source of eDNA with far reaching implications. First, we conducted a field study to track specific arthropod targets from different spider webs. We then employed high-throughput amplicon sequencing of taxonomic barcodes to investigate the utility of spider web eDNA for biodiversity monitoring of animals, fungi and bacteria. Our results show that genetic remains on spider webs allow the detection of even the smallest target organisms. We also demonstrate that eDNA from spider webs is useful in research of community compositions in different domains of life, with potentially highly detailed temporal and spatial information.

ecology↗