Biology subjects

Yanuka-Golub, K.

Publications and source records attributed to Yanuka-Golub, K..

4 recordsLinked to original sources

bioRxiv2026

Invasive plant soil legacies shape microbial function and community organization under short-term carbon and nitrogen amendments

Plant invasion can modify soil microbial communities and ecosystem processes through plant-soil feedbacks, yet it remains unclear whether these effects are expressed mainly through taxonomic turnover or through shifts in microbial function and interaction structure. We tested how soil legacy generated by the invasive Conyza bonariensis, the native Helminthotheca echioides, or unplanted control soil influenced short-term microbial responses to standardized amendments and plant-derived inputs. In Experiment 1, conditioned soils were amended with water, cellulose, or ammonium and analyzed for extracellular enzyme activity, qPCR-based gene abundance, bacterial community composition, and family-level co-occurrence networks. In Experiment 2, the same soil legacies were exposed to water, glucose, or sterile root exudates from native or invasive plants. Native- and invasive-conditioned soils differed significantly in composition, but they were not consistently distinguished by strong indicator taxa, indicating that legacy effects were expressed mainly through redistribution of shared taxa rather than community turnover. In contrast, functional responses were clearer: enzyme activity and nirS abundance showed strong soil-legacy dependence, and network analysis revealed that invasive-conditioned soil supported a denser, more positive, and more compact family-level association structure than native-conditioned soil. In Experiment 2, invasive root exudates produced stronger short-term functional-based differentiation among soil legacies than native exudates, especially for extracellular enzymes. Together, the two experiments show that plant invasion can leave a persistent belowground legacy that is expressed primarily through functional filtering and network rewiring of a broadly shared microbiome, rather than through major taxonomic turnover alone.

microbiology↗

bioRxiv2026

Warming and resource enrichment decouple growth from enzymatic investment, shifting the competitive balance between native and invasive plants

Invasive plants can reshape ecosystems by altering soil biogeochemistry and microbial functioning under global change. Competitive interactions between the invasive Conyza bonariensis and the native Helminthotheca echioides were evaluated under warming, nitrogen enrichment, and elevated CO2, together with rhizosphere microbial function in solitary versus competitive growth. Plants were grown alone or in interspecific competition under elevated temperature (27 vs 29 {degrees}C), ammonium-nitrate fertilization versus no fertilization, and ambient versus elevated CO2 (400 vs 720 ppm). Plant traits and relative growth rate (RGR) were measured alongside potential extracellular enzyme activities (EEA) of -D-glucosidase (C acquisition) and N-acetyl-{beta}-D-glucosaminidase (NAGase; N acquisition) and functional gene abundances (nirS and bacterial amoA). To relate enzyme signals to plant demand and microbial biomass, we calculated a growth-normalized rhizosphere investment metric (Specific Rhizosphere Index; SRI) and a biomass-normalized investment metric (Specific Enzyme Activity; SEA). Competition effects were summarized as {Delta}SRI and {Delta}Tax (change from alone to competition) to quantify how competition altered growth- and biomass-normalized investment. Plant responses were driver- and context-dependent. Elevated CO2 produced the largest changes in growth traits, especially for the invasive species. Warming effects were modest in solitary plants but became apparent under competition, where elevated temperature reduced competitive suppression via increased invasive leaf production and reduced constraints on native leaf expansion. Fertilization caused comparatively small shifts in plant endpoints. Microbial responses depended strongly on soil conditioning history. Potential EEA showed limited shifts with warming and fertilization, whereas elevated CO2 enhanced NAGase mainly in invasive-conditioned soils and increased nirS across soils. Despite overlap in ecoenzymatic stoichiometry, SRI and {Delta}Tax revealed treatment- and legacy-dependent patterns in how competition re-scaled microbial C and N acquisition relative to plant growth and microbial biomass. Together, these results indicate that global change can decouple plant growth from enzymatic investment and reconfigure invasive-native interactions through shifts in above-belowground coupling.

microbiology↗

bioRxiv2023

Allochthonous groundwater microorganisms affect coastal seawater microbial abundance, activity and diversity

Submarine groundwater discharge (SGD) is a globally important process supplying nutrients and trace elements to the coastal environment, thus playing a pivotal role in sustaining marine primary productivity. Along with nutrients, groundwater also contains allochthonous microbes that are discharged from the terrestrial subsurface into the sea. Currently, little is known about the interactions between groundwater-borne and coastal seawater microbial populations, and their role upon introduction to coastal seawater populations. Here, we investigated seawater microbial abundance, activity and diversity in a site strongly influenced by SGD (in-situ observations), and through laboratory-controlled bottle incubations mimicking different mixing scenarios between SGD (either ambient or filtered through 0.1 {micro}m/0.22 {micro}m) and seawater. Our results demonstrate that the addition of <0.1 {micro}m SGD stimulated heterotrophic activity and increased microbial abundance compared to control, whereas <0.22 {micro}m filtration treatments induced primary productivity rates and Synechococcus growth. Amplicon sequencing of the 16S rRNA gene showed a strong shift from a SAR11-rich community in the reference SGD-unaffected coastal samples to a Rhodobacteraceae-dominated one in the <0.1 {micro}m treatment, in agreement with their in-situ enrichment in the SGD field site. These results suggest that despite the significant nutrient input, microbes delivered by SGD may affect the abundance, activity and diversity of intrinsic microbes in coastal seawater. Our results highlight the cryptic interplay between groundwater and seawater microbes in coastal environments, which has important implications for carbon cycling and climate. Key PointsO_LIGroundwater discharge into the coastal zone delivers both nutrients and allochthonous microbes. C_LIO_LIGroundwater microbes interact with seawater populations, by which affecting the delicate autotroph-heterotroph balance. C_LIO_LISubterranean microbial processes are key drivers of food webs, potentially affecting biogenic carbon fluxes in the ocean and climate. C_LI

microbiology↗

bioRxiv2020

Anode surface bioaugmentation enhances deterministic biofilm assembly in microbial fuel cells

Microbial fuel cells (MFCs) are devices that can generate energy while aiding biodegradation of waste through the activity of an electroactive mixed biofilm. Metabolic cooperation is considered essential for MFCs efficiency, especially during early-anode colonization. Yet, the specific ecological processes that drive the assembly of an optimized anode-attached community remain unknown. Here, we show, using 16S rRNA gene amplicon and shotgun metagenomic sequencing that bioaugmentation of the anode surface with an electroactive consortium originating from a well-established anodic biofilm, dominated by different Desulfuromonas strains, resulted in an extremely rapid voltage generation (reaching maximal voltage within several hours). This was in sharp contrast to the highly stochastic and slower biofilm assembly that occurred when the anode-surface was not augmented. By comparing two inoculation media, wastewater and filtered wastewater, we were able to illustrate two different "source-communities" for newly arriving species that with time colonized the anode surface in a different manner and resulted in dramatically different community assembly processes. Remarkably, an efficient anode colonization process was obtained only if unfiltered wastewater was added, leading to a near-complete replacement of the bioaugmented community by Geobacter lovleyi. We propose that anode bioaugmentation reduced stochasticity by creating available niches that were quickly occupied by specific newly-arriving species that positively supported the fast establishment of a highly-functional anode biofilm.

microbiology↗