Biology subjects

Salazar, G.

Publications and source records attributed to Salazar, G..

17 recordsLinked to original sources

bioRxiv2026

Unexpected excess heterozygosity in a threatened, mycoheterotrophic, self-pollinating orchid

Self-fertilization results in reduction of heterozygosity over time, accelerated by small population sizes, restricted ranges, and fragmented habitats. Yet some species maintain heterozygosity despite these factors. One is Corallorhiza bentleyi, a threatened, mycoheterotrophic, self-pollinating orchid restricted to Virginia and West Virginia, USA. Reduced representation sequencing was employed across five of the ~12 known localities of C. bentleyi, including representatives of sister species C. involuta from Mexico, to quantify patterns of population structure and genomic diversity. Surveys of C. bentleyi revealed a predominance of the cleistogamous (closed-flowered) growth form. Differentiation was observed between the two species but with weak population structure in C. bentleyi. Surprisingly, excess heterozygosity and negative inbreeding were recovered in both species, counter to expectations. Analyses provided evidence against bioinformatic artifacts (collapsed paralogs), small-sample bias (Robertson effect), and accumulation of mutations along chromosomes due to low recombination associated with selfing (Meselson effect) as explanations for excess heterozygosity. Demographic analyses favored a model of post-glacial divergence among C. bentleyi and C. involuta lacking bottlenecks. Finally, simulations under alternative selection scenarios favored models of overdominance vs. those of negative frequency dependent selection. It was concluded that overdominance, namely selection against selfed homozygotes, is the most likely explanation for elevated heterozygosity in C. bentleyi. Conservation concerns are discussed in light of these findings and the threats of extinction for one of the most vulnerable orchid species in North America.

evolutionary biology↗

bioRxiv2026

Sex Effect of E-liquid Constituents on Atherosclerosis and Gut Dysbiosis in ApoE-/- Mice

RationaleThe role of sex in the effects of vaping and individual aerosolized e-liquid constituents on atherosclerosis, vascular aging, and gut microbiome remodeling remains poorly characterized. ObjectiveTo determine the contribution of e-cigarette aerosol components to vascular senescence, atherosclerosis, and gut microbiome dysbiosis in ApoE-/- mice and vascular smooth muscle cell (VSMC) viability and senescence. MethodsMale and female ApoE-/- mice were exposed to e-liquid constituents (vehicle, vehicle plus nicotine, and vehicle plus nicotine plus menthol) for 48 minutes per day, 5 days per week for 16 weeks, with vascular pathology assessed in vivo. VSMCs isolated from aortas of wild-type and ApoE-/- male and female mice were exposed to aerosolized e-liquids and evaluated for cellular senescence. ResultsExposure to all tested e-liquid formulations, including vehicle, nicotine-containing, and menthol-containing aerosols, increased atherosclerosis in both male and female mice, with the most robust effects observed in the nicotine-containing formulation and in the descending aorta. Females exhibited greater sensitivity to e-liquid exposure, with increased plaque accumulation in both the aortic arch and descending aorta, while the addition of menthol was associated with reduced plaque burden compared with nicotine alone in both sexes. Novel findings show that e-liquid exposure also altered gut microbial composition in a sex- and exposure-dependent manner, with nicotine causing the greatest dysbiosis and menthol exerting modulatory, but not restorative, effects. Notably, Alloprevotella emerged as a key discriminating genus associated with reduced plaque burden, supporting a potential link between gut microbial remodeling, inflammatory regulation, and atherosclerosis. ConclusionsThese findings demonstrate that individual e-liquid aerosol components increase atherosclerosis and alter the gut microbiome in a sex-specific manner, with nicotine producing the most pronounced pro-atherogenic effects and the addition of menthol reducing these effects, without eliminating overall atherosclerotic risk.

physiology↗

bioRxiv2026

Dissetangling the Vine: Phylogenomics and Historical Biogeography of Vanilla (Orchidaceae)

Renowned for its aromatic fruits and economic importance, the genus Vanilla poses longstanding taxonomic and phylogenetic challenges. Despite recent molecular studies, a comprehensive species tree is lacking, and the evolutionary processes and historical patterns shaping the genus remain poorly understood. We present a new, comprehensive phylogenomic framework for Vanilla, based on 349 low-copy nuclear genes and 76 plastid loci from the Angiosperms353 probe set, which we used to infer evolutionary relationships, assess cyto-nuclear and gene-species tree discordance, and thoroughly investigate its historical distribution and diversification. Sampling 43% of the genus, our framework resolves phylogenetic uncertainties, clarifies major clades, confirms prior hypotheses, and reveals novel placements, including V. planifolia and Vanilla subg. Gondwana. Discordances are primarily driven by incomplete lineage sorting, particularly in the vanillin-producing clade, with evidence of both ancient and recent hybridization, including a natural hybrid from the Yucatan Peninsula. Biogeographic analyses indicate a Guiana Shield origin ([~]30 Mya), Amazonia as a major diversification source, the Andes as a permeable barrier, and Central America as the main diversification sink. This study provides a robust evolutionary framework for Vanilla, supporting taxonomic revisions, comparative trait analyses, and a deeper understanding of the processes shaping this economically and biologically important orchid genus.

evolutionary biology↗

bioRxiv2025

Identification of novel interacting proteins of FUZ and GPR161.

Proteins modulate signaling pathways through dynamic protein-protein interactions, which provide critical insights into the underlying mechanisms of cellular processes leading to human diseases. Our previous study revealed the biochemical and genetic interactions between FUZ and GPR161 that regulate sonic hedgehog signaling during spinal neural tube development. This study aimed to identify novel co-interacting proteins of FUZ and GPR161 and explore their biochemical and functional associations. We performed affinity-based liquid chromatography-tandem mass spectrometry on immunoprecipitated FUZ and GPR161 proteins. Using this approach, we identified 159 co-interacting proteins, of which 289 proteins that interacted exclusively with FUZ and 617 proteins that interacted exclusively with GPR161. Gene Ontology (GO) analysis of the FUZ and GPR161 co-interactome revealed an enrichment of proteins associated with proteasomal catabolic processes and trafficking. GO analysis of the exclusive FUZ and GPR161 interactomes identified cell cycle progression, mitochondrial membrane, RNA metabolism, receptor complex, and Endoplasmic Reticulum-Golgi transport. These findings were further validated using STRING network analysis. Among the identified proteins, we prioritized FKBP8 and confirmed its biochemical interactions with both FUZ and GPR161 exclusively. In summary, our proteomic profiling uncovered the protein network of FUZ and GPR161, revealing their individual and cooperative functions in multiple cellular processes. Statement of Significance- The functional link between FUZ and GPR161 remains unknown, while our previous study showed their genetic and biochemical link in regulating sonic hedgehog signaling during spinal neural tube development. - This study identified the protein network involving FUZ and GPR161 using affinity- based mass spectrometry combining with gene ontology and STRING analysis, providing the novel molecular regulatory role of FUZ and GPR161. - We prioritized the proteins, FKBP8, as a co-interacting partners of FUZ and GPR161, and validated their biochemical interaction. We identified the FUZ-GPR161-FKBP8 forms protein complex, and their interaction was not exclusive, suggesting those three proteins located in the same signaling pathway potentially regulating spinal neural tube development.

biochemistry↗

bioRxiv2024

Metazoan diversity in Chilean hypersaline lakes unveiled by environmental DNA

Saline and hypersaline wetlands are biodiversity hotspots for metazoans such as aquatic invertebrates and wading birds. However, the survival of these habitats and their biota is increasingly threatened by a combination of pressures from climate change and extractive processes, jeopardizing the long-term ecological functioning of these ecosystems. With the goal of improving conservation efforts through state-of-the-art survey techniques in hypersaline ecosystems, this study tests the use of environmental DNA (eDNA) methods for metazoan biomonitoring. We employed a multi-assay approach utilizing three genetic markers--12S rRNA, 18S rRNA, and COI --to analyze biodiversity in two types of environmental substrates, sediment and water. These samples were collected from three hypersaline lakes situated at high altitude in Northern Chile: Salar de Atacama (Laguna Puilar), Salar de Pujsa, and Salar de Tara. In addition, we compared the eDNA outputs with results generated from aquatic macroinvertebrate assessments using kick-nets to evaluate the potential for complementary sampling approaches. Our eDNA analyses revealed a total of 21 and 22 taxa across the three hypersaline lakes in sediment and water, respectively. Within both substrates, the highest diversity was found in Salar de Tara (15 taxa within sediment and 13 taxa from water). Our multi-assay design was able to detect a range of resident hypersaline taxa with different conservation status, spanning from rotifers (Encentrum) to endangered snails (Heleobia atacamensis), to amphipods (Hyalella) and flamingos (Pheonicopterus). Macroinvertebrate presence/absence data derived from conventional kick-net surveys further validated Salar de Tara as the most biodiverse system. Compared to net-based assessments, eDNA analysis allowed more refined taxonomic assignments for copepods and ostracods, while certain taxa such as Ephydridae or Hirudinea were not detected through molecular tests. Overall, this study provides evidence that eDNA is an effective tool to elucidate fine scale taxa assemblages and can refine conservation efforts in hypersaline lakes. Given the fast pace of research developments in the field of molecular ecology, eDNA hosts great potential to become a central actor in hypersaline bioassessments in the near future.

ecology↗

bioRxiv2024

Glia multitask to compensate for neighboring glial cell dysfunction

As glia mature, they undergo glial tiling to abut one another without invading each others boundaries. Upon the loss of the secreted neurotrophin Spatzle3 (Spz3), Drosophila cortex glia transform morphologically and lose their intricate interactions with neurons and surrounding glial subtypes. Here, we reveal that all neighboring glial cell types (astrocytes, ensheathing glia, and subperineurial glia) react by extending processes into the previous cortex glial territory to compensate for lost cortex glial function and reduce the buildup of neuronal debris. However, the loss of Spz3 alone is not sufficient for glia to cross their natural borders, as blocking CNS growth via nutrient-restriction blocks the aberrant infiltration induced by the loss of Spz3. Surprisingly, even when these neighboring glia divert their cellular resources beyond their typical borders to take on new compensatory roles, they are able to multitask to continue to preserve their own normal functions to maintain CNS homeostasis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/611719v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1a1a884org.highwire.dtl.DTLVardef@3ea222org.highwire.dtl.DTLVardef@676b7org.highwire.dtl.DTLVardef@5c21d6_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

The Role of Sex in the Effects of Smoking and Nicotine in Cardiovascular Function, Atherosclerosis, and Inflammation

cigarette smoke (CS) invokes an inflammatory response involving increased levels of circulating cytokines and chemokines, vascular dysfunction, and atherosclerosis. The role of sex and nicotine in CS effects in cardiovascular function and atherosclerosis is unexplored. To assess the role of sex, male and female C57Bl/6 WT (wild type) and ApoE-/- mice were exposed to CS and nicotine for 16 weeks to bridge this literature gap. Heart rate and endothelial function were measured in the aorta of WT mice, while plasma levels of lipids, cytokines and chemokines and aortic plaque burden was assessed in ApoE-/- mice. CS increased heart rate to similar levels in both sexes and induced a stronger impairment in endothelial function in males and more plaque in females than nicotine. Females showed a higher necrotic core area at basal compared with males, while males had a higher calcification area than females by CS. Senescence-associated GLB1/-galactosidase (SA-GLB1) activity was elevated similarly in both sexes by both treatments. Total cholesterol (TC) was elevated by CS in both sexes. CS increased triglycerides (TG), very-low density lipoprotein (VLDL) and high-density lipoprotein (HDL) only in males and low-density lipoprotein (LDL) only in females. Interleukin 17A (IL17A) was upregulated by CS and nicotine in both sexes, while CS upregulated C-X-C motif chemokine ligand 5 (CXCL5/LIX) and interleukin 1 alpha (IL1A) in males and females, respectively. Additionally, nicotine metabolism showed sex specific responses to nicotine, but not smoking. Overall, we identified sex-specific pro-atherogenic responses to CS in the lipid profile, plaque area and composition and inflammatory markers. Males present a stronger impairment in endothelia dysfunction in WT mice, while females a stronger plaque burden in ApoE-/- mice exposed to CS. Elevated HDL and estrogens in males may offer partial protection against the harmful effects of CS. In contrast, elevated LDL and a pro-inflammatory state may promote a stronger pro-atherogenic phenotype in females exposed to CS.

cell biology↗

bioRxiv2023

The Duality of Adiponectin and the Role of Sex in Atherosclerosis

Adiponectin, a hormone highly abundant in circulation, has many beneficial effects in atherosclerosis; however, gene deficiency of this hormone or its receptor have shown detrimental effects on plaque burden in mice. Our objective was to understand the role of sex and aging in the effects of adiponectin deficiency on plaque content, inflammation, and the mechanisms regulating the phenotype of adipoq-/- vascular smooth muscle cells (VSMCs). Even a 50% reduction in the expression of adiponectin led to a plaque reduction in males and an increase in females, compared with apoe-/-controls. Plaque reduction may be attributable to chemokines upregulated in males and downregulated in females. Changes in plaque were not attributed to changes in cholesterol or cardiovascular disease (CVD) markers. In old mice, both genotypes and sexes accumulated more plaque than apoe-/-. RNA sequencing of VSMCs from male mice in vitro uncovered a critical role for adiponectin in AKT signaling, regulation of the extracellular matrix, and TGF-{beta} signaling. Upregulation of AKT activity mediated proliferation and migration of adipoq-/-cells. Activation of AMPK with metformin or AdipoRon reduced AKT-dependent proliferation and migration of adipoq-/- cells but did not improve the expression of contractile genes. Anti-atherogenic mechanisms targeted the ECM in adipoq-/- cells, downregulating MMP2 and 9 and upregulating decorin. Our study uncovered sex and age-dependent effects of adiponectin deficiency in atherosclerosis.

physiology↗

bioRxiv2022

Abundant deep ocean heterotrophic bacteria are culturable

Traditional culture techniques usually retrieve only a small fraction of the environmental marine microbial diversity, which mainly belong to the so-called rare biosphere. However, this paradigm has not been fully tested at a broad scale, especially in the deep ocean. Here, we examined the fraction of heterotrophic bacterial communities in photic and deep ocean layers that could be recovered by culture-dependent techniques at a large scale. We compared 16S rRNA gene sequences from a collection of 2003 cultured isolates of heterotrophic marine bacteria with global 16S rRNA metabarcoding datasets (16S TAGs) covering surface, mesopelagic and bathypelagic ocean samples that included 16 of the 22 samples used for isolation. These global datasets represent 60,322 unique 16S amplicon sequence variants (ASVs). Our results reveal a significantly higher proportion of isolates identical to ASVs in deeper ocean layers reaching up to a 28% of the 16S TAGs of the bathypelagic microbial communities, which included the isolation of 3 of the top 10 most abundant 16S ASVs in the global bathypelagic ocean, related to the genera Sulfitobacter, Halomonas and Erythrobacter. These cultured isolates contributed differently to the prokaryotic communities across different plankton size fractions, recruiting between 38% in the free-living size fraction (0.2-0.8 m) and up to 45% in the largest plankton size fraction (20-200 m) in the bathypelagic ocean. Our findings support the hypothesis that sinking particles in the bathypelagic realm act as resource-rich habitats, suitable for the growth of heterotrophic bacteria with a copiotroph lifestyle that can be cultured, and that these cultivable bacteria can also thrive as free-living bacteria.

ecology↗

bioRxiv2022

The IPDGC/GP2 Hackathon - an open science event for training in data science, genomics, and collaboration using Parkinson's disease data

BackgroundOpen science and collaboration are necessary to facilitate the advancement of Parkinsons disease (PD) research. Hackathons are collaborative events that bring together people with different skill sets and backgrounds to generate resources and creative solutions to problems. These events can be used as training and networking opportunities. ObjectiveTo coordinate a virtual hackathon to develop novel PD research tools. Methods49 early career scientists from 12 countries collaborated in a virtual 3-day hackathon event in May 2021, during which they built tools and pipelines with a focus on PD. Resources were created with the goal of helping scientists accelerate their own research by having access to the necessary code and tools. ResultsEach team was allocated one of nine different projects, each with a different goal. These included developing post-genome-wide association studies (GWAS) analysis pipelines, downstream analysis of genetic variation pipelines, and various visualization tools. ConclusionHackathons are a valuable approach to inspire creative thinking, supplement training in data science, and foster collaborative scientific relationships, which are foundational practices for early career researchers. The resources generated can be used to accelerate research on the genetics of PD.

genetics↗

bioRxiv2021

The quality of dissolved organic matter shapes the biogeography of the active bathypelagic microbiome

The bathypelagic ocean (1000-4000 m depth) is the largest aquatic biome on Earth but it is still largely unexplored. Due to its prevalent low dissolved organic carbon concentrations, most of the prokaryotic metabolic activity is assumed to be associated to particles. The role of free-living prokaryotes has thus been mostly ignored, except that of some chemolithoautotrophic lineages. Here we used a global bathypelagic survey of size-fractionated metagenomic and 16S (genes and transcripts) data and performed a differential abundance analysis to explore the functional traits of the different prokaryotic life-strategies, their contribution to the active microbiome, and the role that the quality of the dissolved organic matter (DOM) plays in driving this contribution. We found that free-living prokaryotes have limited capacity to uplift their metabolism in response to environmental changes and display comparatively lower growth rates than particle associated prokaryotes, but are responsible for the synthesis of vitamins in the bathypelagic. Furthermore, their contribution to the active prokaryotic microbiome increased towards waters depleted of labile DOM, which represented a large fraction of the tropical and subtropical ocean sampled stations. This points to a relevant yet overlooked role of free-living prokaryotes in DOM cycling in the vast bathypelagic desert.

ecology↗

bioRxiv2021

Uncharted biosynthetic potential of the ocean microbiome

Microbes are phylogenetically and metabolically diverse. Yet capturing this diversity, assigning functions to host organisms and exploring the biosynthetic potential in natural environments remains challenging. We reconstructed >25,000 draft genomes, including from >2,500 uncharacterized species, from globally-distributed ocean microbial communities, and combined them with [~]10,000 genomes from cultivated and single cells. Mining this resource revealed [~]40,000 putative biosynthetic gene clusters (BGCs), many from unknown phylogenetic groups. Among these, we discovered Candidatus Eudoremicrobiaceae as one of the most biosynthetically diverse microbes detected to date. Discrete transcriptional states structuring natural populations were associated with a potentially niche-partitioning role for BGC products. Together with the characterization of the first Eudoremicrobiaceae natural product, this study demonstrates how microbiomics enables prospecting for candidate bioactive compounds in underexplored microbes and environments.

microbiology↗

bioRxiv2020

Ecogenomics of key prokaryotes in the Arctic Ocean

The Arctic Ocean is a key player in the regulation of climate and at the same time is under increasing pressure as a result of climate change. Predicting the future of this ecosystem requires understanding of the responses of Arctic microorganisms to environmental change, as they are the main drivers of global biogeochemical cycles. However, little is known about the ecology and metabolic potential of active Arctic microbes. Here, we reconstructed a total of 3,550 metagenomic bins from 41 seawater metagenomes collected as part of the Tara Oceans expedition, covering five different Arctic Ocean regions as well as the sub-Arctic North Atlantic Ocean and including various depths and different seasons (spring to autumn). Of these bins, 530 could be classified as Metagenome Assembled Genomes (MAGs) and over 75% of them represented novel species. We describe their habitat range and environmental preferences, as well as their metabolic capabilities, building the most comprehensive dataset of uncultured bacterial and archaeal genomes from the Arctic Ocean to date. We found a prevalence of mixotrophs, while chemolithoautotrophs were mostly present in the mesopelagic Arctic Ocean during spring and autumn. Finally, the catalogue of Arctic MAGs was complemented with metagenomes and metatranscriptomes from the global ocean to identify the most active MAGs present exclusively in polar metagenomes. These polar MAGs, which display a range of metabolic strategies, might represent Arctic sentinels of climate change and should be considered in prospective studies of the future state of the Arctic Ocean.

ecology↗

bioRxiv2020

SIAMCAT: user-friendly and versatile machine learning workflows for statistically rigorous microbiome analyses

The human microbiome is increasingly mined for diagnostic and therapeutic biomarkers using machine learning (ML). However, metagenomics-specific software is scarce and overoptimistic evaluation and limited cross-study generalization are prevailing issues. To address these, we developed SIAMCAT, a versatile R toolbox for ML-based comparative metagenomics. We demonstrate its capabilities in a meta-analysis of fecal metagenomic studies (10,803 samples). When naively transferred across studies, ML models lost accuracy and disease specificity, which could however be resolved by a novel training set augmentation strategy. This revealed some biomarkers to be disease-specific, others shared across multiple conditions. SIAMCAT is freely available from siamcat.embl.de.

bioinformatics↗

bioRxiv2019

Diversity patterns of marine heterotrophic culturable bacteria along vertical and latitudinal gradients

Nowadays, there is a significant gap in the knowledge of the diversity and patterns for marine heterotrophic culturable microorganisms. In addition, most of the bacterial isolation efforts have focused on the photic ocean leaving the deep ocean less explored. We have isolated 1561 bacterial strains covering both photic (817) and aphotic layers (744) including isolates from the oxygen minimum zone (362) and the bathypelagic (382) from a variety of oceanographic regions including the North Western Mediterranean Sea, the North and South Atlantic Oceans, the Indian, the Pacific, and the Arctic Oceans. The partial sequencing of the 16S rRNA gene of all isolates revealed that they mainly affiliate with the classes Alphaproteobacteria (35.9%) and Gammaproteobacteria (38.6%), as well as, phylum Bacteroidetes (16.5%). The genera Alteromonas and Erythrobacter were the most widespread heterotrophic bacteria in the ocean able to grow on solid agar media. When comparing the sequences of all isolates, 37% of them were 100% identical. In fact, we found that 59% of the total aphotic isolates were 100% identical to photic isolates, indicating the ubiquity of some bacterial isolates along the water column. Unweighted UniFrac distances did not show significant differences among stations regardless of their geographic distance or depth, reflecting the wide dispersion of the culturable bacterial assemblage. This isolates collection provides an overview of the distribution patterns of cosmopolitan marine culturable heterotrophic bacteria.

microbiology↗

bioRxiv2019

Metabolic Architecture of the Deep Ocean Microbiome

The deep sea, the largest compartment of the ocean, is an essential component of the Earth system, but the functional exploration of its microbial communities lags far behind that of other marine realms. Here we analyze 58 bathypelagic microbial metagenomes from the Atlantic, Indian, and Pacific Oceans in an unprecedented sampling effort from the Malaspina Global Expedition, to resolve the metabolic architecture of the deep ocean microbiome. The Malaspina Deep-Sea Gene Collection, 71% of which consists of novel genes, reveals a strong dichotomy between the functional traits of free-living and particle-attached microorganisms, and shows relatively patchy composition challenging the paradigm of a uniform dark ocean ecosystem. Metagenome Assembled Genomes uncovered 11 potential new phyla, establishing references for deep ocean microbial taxa, and revealed mixotrophy to be a widespread trophic strategy in the deep ocean. These results expand our understanding of the functional diversity, metabolic versatility, and carbon cycling in the largest ecosystem on Earth.\n\nOne Sentence SummaryA whole community genomic survey of the deep microbiome sheds light on the microbial and functional diversity of the dark ocean.

microbiology↗

bioRxiv2018

Different processes shape prokaryotic and picoeukaryotic assemblages in the sunlit ocean microbiome

The smallest members of the sunlit-ocean microbiome (prokaryotes and picoeukaryotes) participate in a plethora of ecosystem functions with planetary-scale effects. Understanding the processes determining the spatial turnover of this assemblage can help us better comprehend the links between microbiome species composition and ecosystem function. Ecological theory predicts that selection, dispersal and drift are main drivers of species distributions, yet, the relative quantitative importance of these ecological processes in structuring the surface-ocean microbiome is barely known. Here we quantified the role of selection, dispersal and drift in structuring surface-ocean prokaryotic and picoeukaryotic assemblages by using community DNA-sequence data collected during the global Malaspina expedition. We found that dispersal limitation was the dominant process structuring picoeukaryotic communities, while a balanced combination of dispersal limitation, selection and drift shaped prokaryotic counterparts. Subsequently, we determined the agents exerting abiotic selection as well as the spatial patterns emerging from the action of different ecological processes. We found that selection exerted via temperature had a strong influence on the structure of prokaryotic communities, particularly on species co-occurrences, a pattern not observed among communities of picoeukaryotes. Other measured abiotic variables had limited selective effects on microbiome structure. Picoeukaryotes presented a higher differentiation between neighbouring communities and a higher distance-decay when compared to prokaryotes, agreeing with their higher dispersal limitation. Finally, drift seemed to have a limited role in structuring the sunlit-ocean microbiome. The different predominance of ecological processes acting on particular subsets of the ocean microbiome suggests uneven responses to environmental change.\n\nSIGNIFICANCE STATEMENTThe global ocean contains one of the largest microbiomes on Earth and changes on its structure can impact the functioning of the biosphere. Yet, we are far from understanding the mechanisms that structure the global ocean microbiome, that is, the relative importance of environmental selection, dispersal and random events (drift). We evaluated the role of these processes at the global scale, based on data derived from a circumglobal expedition and found that these ecological processes act differently on prokaryotes and picoeukaryotes, two of the main components of the ocean microbiome. Our work represents a significant contribution to understand the assembly of marine microbial communities, providing also insights on the links between ecological mechanisms, microbiome structure and ecosystem function.

ecology↗