Search NASA⌕ Search

SEARCH · Search NASA

Results for “Translocation”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Action at a distance: The remarkable coupling of CO 2 uptake to electron transfer in specialized cyanobacterial NDH-1 complexes

Cyanobacteria achieve highly efficient photosynthesis using a CO 2 -concentrating mechanism relying on specialized Type I (NDH-1) complexes. Among these, NDH-1 3 and NDH-1 4 catalyze redox-coupled hydration of CO 2 to bicarbonate, supporting carbon fixation in carboxysomes. The mechanism of coupling electron transfer to CO 2 -hydration by these variant NDH-1 complexes remains unknown. We engineered a Synechococcus PCC7942 strain that expresses exclusively the high flux/low affinity NDH-14 complex, enabling the observation of the coupling of CO 2 hydration to cyclic electron flow in isolation from the other NDH-1 isoforms normally present in cells. We found that inhibition of the CupB protein by the carbonic anhydrase inhibitor ethoxzolamide (EZ) suppressed CO 2 uptake, slowed photosystem I rereduction, and abolished proton pumping as probed by acridine orange fluorescence. These effects were absent in strains lacking Cup proteins, confirming specificity. The results demonstrate that CO 2 hydration and electron transfer through NDH-14 are tightly coupled via proton translocation across the thylakoid membrane. These findings provide direct evidence for the bidirectional interaction in bioenergetic coupling between the plastoquinone reduction and the CO 2 uptake at the distal Zn-site over a span of ~150 Å and support a proton-removal hypothesis involving the proton transfer pathways from the Zn-site of CO2 hydration to an energetically coupled proton loading site evolutionarily repurposed from the ancestral proton pumping mechanism to enable energetic CO 2 uptake.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Foliar elemental distribution in Blepharidium guatemalense assessed by synchrotron X-ray fluorescence spectroscopy and colorimetric optical microscopy

The hyperaccumulation phenomenon holds significant potential for Ni agromining in ultramafic areas; however, data on tropical hyperaccumulator species, particularly regarding metal distribution and tolerance mechanisms, remain scarce. Here, this study characterized the foliar elemental distribution of Blepharidium guatemalense, analyzed its metal localization at both tissue and cellular levels, and quantified its Ni accumulation when grown in Brazilian ultramafic soil. Plants were grown in pots for 90 days, and Ni concentrations in the aerial biomass and bio-ore were determined. Synchrotron-based micro-X-ray fluorescence (S-µXRF) was used to assess metal distribution in tissues, supplemented by microscopic examination with dimethylglyoxime (DMG) to visualize Ni accumulation in specific cell types. B. guatemalense reached 19,000 mg kg −1 Ni in leaves. Processing leaf biomass produced ash containing 24 wt% Ni, indicating promising metal-recovery potential for the species. S-µXRF revealed that Ni was predominantly localized in the central and secondary veins of the leaves, suggesting efficient vascular transport. Microscopic analysis using the colorimetric reagent DMG further showed that Ni accumulation occurs near the epidermis and phloem, suggesting that B. guatemalense employs specific physiological mechanisms for Ni translocation, potentially supporting both defense and growth functions. These results establish B. guatemalense as a promising candidate for large-scale Ni agromining in tropical regions.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Chromosome compartmentalization alterations in prostate cancer cell lines model disease progression

Prostate cancer aggressiveness and metastatic potential are influenced by gene expression and genomic aberrations, features that can be influenced by the 3D structure of chromosomes inside the nucleus. Using chromosome conformation capture (Hi-C), we conducted a systematic genome architecture comparison on a cohort of cell lines that model prostate cancer progression, from normal epithelium to bone metastasis. We describe spatial compartment identity (A-open versus B-closed) changes with progression in these cell lines and their relation to gene expression changes in both cell lines and patient samples. In particular, 48 gene clusters switch from the B to the A compartment, including androgen receptor, WNT5A, and CDK14. These switches are accompanied by changes in the structure, size, and boundaries of topologically associating domains (TADs). Further, compartment changes in chromosome 21 are exacerbated with progression and may explain, in part, the genesis of the TMPRSS2-ERG translocation. These results suggest that discrete 3D genome structure changes play a deleterious role in prostate cancer progression.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Structural basis for severe pain caused by mutations in the voltage sensors of sodium channel NaV1.7

Voltage-gated sodium channels in peripheral nerves conduct nociceptive signals from nerve endings to the spinal cord. Mutations in voltage-gated sodium channel NaV1.7 are responsible for a number of severe inherited pain syndromes, including inherited erythromelalgia (IEM). Here, we describe the negative shifts in the voltage dependence of activation in the bacterial sodium channel NaVAb as a result of the incorporation of four different IEM mutations in the voltage sensor, which recapitulate the gain-of-function effects observed with these mutations in human NaV1.7. Crystal structures of NaVAb with these IEM mutations revealed that a mutation in the S1 segment of the voltage sensor facilitated the outward movement of S4 gating charges by widening the pathway for gating charge translocation. In contrast, mutations in the S4 segments modified hydrophobic interactions with surrounding amino acid side chains or membrane phospholipids that would enhance the outward movement of the gating charges. These results provide key structural insights into the mechanisms by which these IEM mutations in the voltage sensors can facilitate outward movements of the gating charges in the S4 segment and cause hyperexcitability and severe pain in IEM. Our work gives new insights into IEM pathogenesis at the near-atomic level and provides a molecular model for mutation-specific therapy of this debilitating disease.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Cytogenetic follow-up studies on humans with internal and external exposure to ionizing radiation

Cells exposed to ionizing radiation have a wide spectrum of DNA lesions that include DNA single-strand breaks, DNA double-strand breaks (DSBs), oxidative base damage and DNA-protein crosslinks. Among them, DSB is the most critical lesion, which when mis-repaired leads to unstable and stable chromosome aberrations. Currently, chromosome aberration analysis is the preferred method for biological monitoring of radiation-exposed humans. Here, stable chromosome aberrations, such as inversions and balanced translocations, persist in the peripheral blood lymphocytes of radiation-exposed humans for several years and, therefore, are potentially useful tools to prognosticate the health risks of radiation exposure, particularly in the hematopoietic system. In this review, we summarize the cytogenetic follow-up studies performed by REAC/TS (Radiation Emergency Assistance Center/Training site, Oak Ridge, USA) on humans exposed to internal and external radiation. In the light of our observations as well as the data existing in the literature, this review attempts to highlight the importance of follow-up studies for predicting the extent of genomic instability and its impact on delayed health risks in radiation-exposed victims.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2025

Identification of candidate host-specificity genes in Exserohilum turcicum using comparative genomics and transcriptomics

Abstract Exserohilum turcicum causes northern corn leaf blight and sorghum leaf blight. While the same species cause disease in both crops, the strains are host-specific. Here, we report the sequence and de novo annotated assemblies of one sorghum- and one maize-specific E. turcicum strain. The strains were sequenced using the PacBio Sequel II system. The total genome length for both assemblies was between 44 and 45 Mb with N50 of ∼2.5 Mb. Ninety-eight percent of the Benchmarking Universal Single-Copy Orthologs (BUSCO) for both assemblies had complete status. The estimated number of genes was 11,762 and 12,029 in the sorghum- and maize-specific isolates, respectively. Funannotate, EffectorP, SignalP, and transcriptome data were used to create functional annotation of each genome. The whole-genome comparison identified ten large-scale inversions and three translocations between the maize- and sorghum-specific strains, along with homologous genes and gene duplications. RNA was sequenced from the maize- and sorghum-specific isolate 10 days post-inoculation in maize and sorghum and from axenic cultures. Gene expression data from planta and axenic growth experiments were compared for each strain. Candidate host-specificity genes were identified by combining results from whole-genome comparison, synteny analysis, gene annotations, and transcriptome data. Overall, this study identified several candidate host-specificity genes that provide insights into E. turcicum interaction with its hosts.

Krone, Mara J. (ORCID:0000000159006624)↗
DOE OSTI2021

Impact of PrsA on membrane lipid composition during daptomycin-resistance-mediated β-lactam sensitization in clinical MRSA strains

Abstract Background The cyclic anionic lipopeptide daptomycin is used in the treatment of severe infections caused by Gram-positive pathogens, including MRSA. Daptomycin resistance, although rare, often results in treatment failure. Paradoxically, in MRSA, daptomycin resistance is usually accompanied by a concomitant decrease in β-lactam resistance in what is known as the ‘see-saw effect’. This resensitization is extensively used for the treatment of MRSA infections, by combining daptomycin and a β-lactam antibiotic, such as oxacillin. Objectives We aimed: (i) to investigate the combined effects of daptomycin and oxacillin on the lipid composition of the cellular membrane of both daptomycin-resistant and -susceptible MRSA strains; and (ii) to assess the involvement of the post-translocational protein PrsA, which plays an important role in oxacillin resistance in MRSA, in membrane lipid composition and remodelling during daptomycin resistance/β-lactam sensitization. Results The combination of microbiological and biochemical studies, with fluorescence microscopy using lipid probes, showed that the lipid composition and surface charge of the daptomycin-resistant cells exposed to daptomycin/oxacillin were dependent on antibiotic concentration and directly associated with PrsA, which influenced cardiolipin remodelling/relocation. Conclusions Our findings show that PrsA, in addition to its post-transcriptional role in the maturation of PBP 2a, is a key mediator of cell membrane remodelling connected to the see-saw effect and may have a key role in the resensitization of daptomycin-resistant strains to β-lactams, such as oxacillin.

de Carvalho, Carla C. C. R.↗
DOE OSTI2026

A Maize GT14 Family Glycosyltransferase Affects Cell Wall Composition and Carbohydrate Export from Source Leaves

Sucrose translocation from photosynthetic leaves to distant parts of a plant, such as seeds and roots, is a critical aspect of plant growth and development and a major determinant of crop yield. To identify genes contributing to this process in maize (Zea mays), we isolated four allelic mutants, carbohydrate partitioning defective7, 48, 49 (cpd7, cpd48, cpd49) and a UniformMu insertion (mu1049954), all of which exhibited reduced growth and fertility and hyperaccumulation of starch and soluble sugars in mature leaves. Consistent with carbohydrate accumulation, cpd7 mutants exhibited reduced sucrose export from mature leaves. Cpd7 encodes a Golgi-resident glucuronosyltransferase belonging to the Glycosyltransferase14 (GT14) family, which is involved in decoration of type II arabinogalactan proteins. No previously described GT14 mutants exhibit reduced sucrose transport or carbohydrate partitioning defects. Additionally, we show that mature leaves of cpd7 mutants have reduced cellulose content and an altered cell wall composition. Further, cpd7 mutants exhibit ectopic phloem lignification likely as a compensatory mechanism for reduced cell wall integrity. Collectively, our data suggest that Cpd7 functions to facilitate cell wall development in the phloem, which is required for efficient sucrose export from mature maize leaves.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Functional Divergence in a Multi-gene Family Is a Key Evolutionary Innovation for Anaerobic Growth in Saccharomyces cerevisiae

The amplification and diversification of genes into large multi-gene families often mark key evolutionary innovations, but this process often creates genetic redundancy that hinders functional investigations. When the model budding yeast Saccharomyces cerevisiae transitions to anaerobic growth conditions, the cell massively induces the expression of seven serine/threonine-rich anaerobically-induced cell wall mannoproteins (anCWMPs): TIP1, TIR1, TIR2, TIR3, TIR4, DAN1, and DAN4. Here, we show that these genes likely derive evolutionarily from a single ancestral anCWMP locus, which was duplicated and translocated to new genomic contexts several times both prior to and following the budding yeast whole genome duplication (WGD) event. Based on synteny and their phylogeny, we separate the anCWMPs into four gene subfamilies. To resolve prior inconclusive genetic investigations of these genes, we constructed a set of combinatorial deletion mutants to determine their contributions toward anaerobic growth in S. cerevisiae. We found that two genes, TIR1 and TIR3, were together necessary and sufficient for the anCWMP contribution to anaerobic growth. Overexpressing either gene alone was insufficient for anaerobic growth, implying that they encode non-overlapping functional roles in the cell during anaerobic growth. We infer from the phylogeny of the anCWMP genes that these two important genes derive from an ancient duplication that predates the WGD event, whereas the TIR1 subfamily experienced gene family amplification after the WGD event. Taken together, the genetic and molecular evidence suggests that one key anCWMP gene duplication event, several auxiliary gene duplication events, and functional divergence underpin the evolution of anaerobic growth in budding yeasts.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

A phage nucleus-associated RNA-binding protein is required for jumbo phage infection

Abstract Large-genome bacteriophages (jumbo phages) of the proposed family Chimalliviridae assemble a nucleus-like compartment bounded by a protein shell that protects the replicating phage genome from host-encoded restriction enzymes and DNA-targeting CRISPR-Cas nucleases. While the nuclear shell provides broad protection against host nucleases, it necessitates transport of mRNA out of the nucleus-like compartment for translation by host ribosomes, and transport of specific proteins into the nucleus-like compartment to support DNA replication and mRNA transcription. Here, we identify a conserved phage nuclear shell-associated protein that we term Chimallin C (ChmC), which adopts a nucleic acid-binding fold, binds RNA with high affinity in vitro, and binds phage mRNAs in infected cells. ChmC also forms phase-separated condensates with RNA in vitro. Targeted knockdown of ChmC using mRNA-targeting dCas13d results in accumulation of phage-encoded mRNAs in the phage nucleus, reduces phage protein production, and compromises virion assembly. Taken together, our data show that the conserved ChmC protein plays crucial roles in the viral life cycle, potentially by facilitating phage mRNA translocation through the nuclear shell to promote protein production and virion development.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Phloem unloading via the apoplastic pathway is essential for shoot distribution of root-synthesized cytokinins

Abstract Root-synthesized cytokinins are transported to the shoot and regulate the growth, development, and stress responses of aerial tissues. Previous studies have demonstrated that Arabidopsis (Arabidopsis thaliana) ATP binding cassette (ABC) transporter G family member 14 (AtABCG14) participates in xylem loading of root-synthesized cytokinins. However, the mechanism by which these root-derived cytokinins are distributed in the shoot remains unclear. Here, we revealed that AtABCG14-mediated phloem unloading through the apoplastic pathway is required for the appropriate shoot distribution of root-synthesized cytokinins in Arabidopsis. Wild-type rootstocks grafted to atabcg14 scions successfully restored trans-zeatin xylem loading. However, only low levels of root-synthesized cytokinins and induced shoot signaling were rescued. Reciprocal grafting and tissue-specific genetic complementation demonstrated that AtABCG14 disruption in the shoot considerably increased the retention of root-synthesized cytokinins in the phloem and substantially impaired their distribution in the leaf apoplast. The translocation of root-synthesized cytokinins from the xylem to the phloem and the subsequent unloading from the phloem is required for the shoot distribution and long-distance shootward transport of root-synthesized cytokinins. This study revealed a mechanism by which the phloem regulates systemic signaling of xylem-mediated transport of root-synthesized cytokinins from the root to the shoot.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Genetically manipulated chloroplast stromal phosphate levels alter photosynthetic efficiency

Abstract The concentration of inorganic phosphate (Pi) in the chloroplast stroma must be maintained within narrow limits to sustain photosynthesis and to direct the partitioning of fixed carbon. However, it is unknown if these limits or the underlying contributions of different chloroplastic Pi transporters vary throughout the photoperiod or between chloroplasts in different leaf tissues. To address these questions, we applied live Pi imaging to Arabidopsis (Arabidopsis thaliana) wild-type plants and 2 loss-of-function transporter mutants: triose phosphate/phosphate translocator (tpt), phosphate transporter 2;1 (pht2;1), and tpt pht2;1. Our analyses revealed that stromal Pi varies spatially and temporally, and that TPT and PHT2;1 contribute to Pi import with overlapping tissue specificities. Further, the series of progressively diminished steady-state stromal Pi levels in these mutants provided the means to examine the effects of Pi on photosynthetic efficiency without imposing nutritional deprivation. ΦPSII and nonphotochemical quenching (NPQ) correlated with stromal Pi levels. However, the proton efflux activity of the ATP synthase (gH+) and the thylakoid proton motive force (pmf) were unaltered under growth conditions, but were suppressed transiently after a dark to light transition with return to wild-type levels within 2 min. These results argue against a simple substrate-level limitation of ATP synthase by depletion of stromal Pi, favoring more integrated regulatory models, which include rapid acclimation of thylakoid ATP synthase activity to reduced Pi levels.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Spatial proteomics reveals signal sequence characteristics correlated with localization in cyanobacteria

Abstract Cyanobacteria have an inner and outer cell membrane enclosing the periplasm and cell wall and an additional set of internal membranes (called the thylakoid membranes) enclosing the thylakoid lumen. The periplasm and thylakoid lumen have unique proteomes, but the mechanisms regulating protein sorting to these locations have remained elusive. Here, proximity-based proteomics using the engineered peroxidase APEX2 was performed in the cyanobacteria Synechococcus sp. PCC 7002 to profile the proteomes of the cytoplasm, thylakoid lumen, and the periplasm and outer membrane (P-OM). Our analyses revealed specific roles for the thylakoid lumen in photosynthesis and energy generation, as well as roles for the periplasm in metabolite transport and binding, cell motility, and cell wall maintenance. Forty proteins localized to both the thylakoid lumen and the P-OM; however, their biological functions remain unclear. We also analyzed the correlation between signal sequence characteristics and differential protein localization to either the thylakoid lumen or the P-OM. In PCC 7002, as well as Synechocystis sp. PCC 6803 and Nostoc sp. PCC 7120, thylakoid lumen proteins translocated across membranes via the Secretory (Sec) system possessed more hydrophobic and alpha-helical signal sequence H-regions than P-OM proteins. The signal sequences of homologous proteins in Gloeobacter violaceus PCC 7421, a cyanobacterial species with a combined thylakoid lumen and periplasmic space, did not exhibit such differences. Therefore, the pattern of increased H-region hydrophobicity and alpha helix content is specific to cyanobacteria with a separate thylakoid lumen space and likely contributes to proper protein sorting between the thylakoid lumen and periplasm.

Plant Sciences↗
DOE OSTI2025

Genomic insights into local adaptation and migration success in reintroduced Coho Salmon of the Wenatchee River basin

ABSTRACT Objective Reintroduction of salmonids into regions where they have been extirpated is a common conservation strategy that is often implemented through natural recolonization, translocation of natural populations, or hatchery-based programs. Locally adapting to specific environmental conditions is critical for long-term population viability, particularly for species like Coho Salmon Oncorhynchus kisutch, which face diverse selective pressures during their migration. This study focused on the mid-Columbia River Coho Salmon reintroduction program managed by Yakama Nation Fisheries, which has successfully reintroduced Coho Salmon into the Wenatchee and Methow River basins, Washington. Notably, these populations have adapted to the longer migration route than those in the founding stock, with selection favoring individuals with an earlier arrival time and that can navigate a 15-km, high-gradient canyon to reach optimal spawning grounds. The objectives of this study were to investigate whether specific genomic regions are under selection for traits associated with return location and timing in Coho Salmon. Methods Low-coverage whole-genome resequencing data were used to screen for genomic regions associated with the phenotypes of interest. Results A weak polygenic signal in female Coho Salmon was found to be associated with return group, with a subset of candidate adaptive regions occurring across eight chromosomes. Conclusions These findings provide insights into the genomic mechanisms underlying local adaptation in reintroduced salmon populations and inform broodstock selection strategies aimed at promoting natural production and long-term population sustainability.

Horn, Rebekah L.↗
DOE OSTI2023

Modulation of polar auxin transport identifies the molecular determinants of source–sink carbon relationships and sink strength in poplar

Abstract Source-to-sink carbon (C) allocation driven by the sink strength, i.e., the ability of a sink organ to import C, plays a central role in tissue growth and biomass productivity. However, molecular drivers of sink strength have not been thoroughly characterized in trees. Auxin, as a major plant phytohormone, regulates the mobilization of photoassimilates in source tissues and elevates the translocation of carbohydrates toward sink organs, including roots. In this study, we used an ‘auxin-stimulated carbon sink’ approach to understand the molecular processes involved in the long-distance source–sink C allocation in poplar. Poplar cuttings were foliar sprayed with polar auxin transport modulators, including auxin enhancers (AE) (i.e., IBA and IAA) and auxin inhibitor (AI) (i.e., NPA), followed by a comprehensive analysis of leaf, stem and root tissues using biomass evaluation, phenotyping, C isotope labeling, metabolomics and transcriptomics approaches. Auxin modulators altered root dry weight and branching pattern, and AE increased photosynthetically fixed C allocation from leaf to root tissues. The transcriptome analysis identified highly expressed genes in root tissue under AE condition including transcripts encoding polygalacturonase and β-amylase that could increase the sink size and activity. Metabolic analyses showed a shift in overall metabolism including an altered relative abundance levels of galactinol, and an opposite trend in citrate levels in root tissue under AE and AI conditions. In conclusion, we postulate a model suggesting that the source–sink C relationships in poplar could be fueled by mobile sugar alcohols, starch metabolism-derived sugars and TCA-cycle intermediates as key molecular drivers of sink strength.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Three-dimensional modeling of hyphal fusion, branching, and nutrient transport in filamentous fungi

Fungi exhibit behaviors distinct from other microbes. Filamentous fungi grow by extending complex networks of branched filaments collectively referred to as the mycelium. These networks can expand over large distances and traverse low-nutrient areas by translocating nutrients through the filament network. This spatial characteristic makes filamentous fungi crucial for soil ecosystems, supporting stable microbial communities and promoting plant growth. However, simulating these behaviors is complex. The elongated nature of fungal compartments results in different mechanical interactions compared to the commonly modeled spherical bacteria. These detailed hyphal mechanics require specialized consideration and are often excluded from conventional fungal simulation packages. Additionally, the extensive fungal networks in nature demand computationally intensive simulations, necessitating high-performance algorithms. Therefore, realistic fungi simulations require specialized software. Here, we introduce a fungal modeling expansion to the high-performance biological modelling and interface exchange (bmx) software suite. bmx leverages adaptive mesh refinement in AMReX for chemical diffusion and incorporates a full mechanical model for bacterial cells, accelerated by GPUs. By extending bmx to model filamentous particles, we demonstrate the formation of complex filament networks through interactions like hyphal branching and fusion (anastomosis). We show that the networks produced match real-world fungal structures through various metrics. This work supports computational studies of fungal growth dynamics and can be adapted to investigate the growth of other filamentous structures in biology or materials science. The expanded-BMX package is open-sourced and is available online.

Cell mechanics↗
DOE OSTI2025

Opposite Response of DNA and RNA Viruses to Soil Warming and Implications for Microbial Functions

Soil viruses control the dynamics and metabolism of their hosts, strongly modifying carbon and nutrient cycling as well as soil biochemistry. Warming specifically affects viruses and their hosts, but the consequences of climate warming on the virus–host interactions, and for soil functions, remain unknown. Here, we investigated the viral communities and the virus–host interactions under warming in situ based on a forest soil column translocation experiment. The abundance of the Petitvirales (DNA viruses) decreased by 25%, but that of the Durnavirales and Martellivirales (RNA viruses) strongly increased. The DNA viral lysogenic signals and RNA viral lytic proteins increased in soil, indicating the opposite lifestyles of DNA and RNA viruses. Correspondingly, the DNA abundance of viral hosts increased, whereas RNA viral hosts remained stable. The high DNA viruses/host ratios reflect very intensive interactions between the virus and host, leading to the drop in the host functions (such as carbon metabolism processes and nitrogen and phosphorus cycles) up to 43%. In contrast, the functions of the hosts for RNA viruses increased by up to 48%. The fundamental difference in behaviour of DNA and RNA viruses is that the former use mainly lysogenic, whereas the latter lytic, lifestyles and thus control the responses of host communities to warming. Conclusively, the opposite response of DNA and RNA viruses to warming in abundance, lifestyle, and interactions with hosts leads to divergent changes in nutrient fluxes in soil. These new perspectives on viral regulations of microbial communities and their function under soil warming reveal the undeniable role of viruses in microbial ecology.

forest soil↗
DOE OSTI2021

Invasion and rapid adaptation of guppies ( Poecilia reticulata ) across the Hawaiian Archipelago

How much does natural selection, as opposed to genetic drift, admixture, and gene flow, contribute to the evolution of invasive species following introduction to a new environment? Here we assess how evolution can shape biological invasions by examining population genomic variation in non-native guppies (Poecilia reticulata) introduced to the Hawaiian Islands approximately a century ago. By examining 18 invasive populations from four Hawaiian islands and four populations from the native range in northern South America, we reconstructed the history of introductions and evaluated population structure as well as the extent of ongoing gene flow across watersheds and among islands. Patterns of differentiation indicate that guppies have developed significant population structure, with little natural or human-mediated gene flow having occurred among populations following introduction. Demographic modeling and admixture graph analyses together suggest that guppies were initially introduced to O‘ahu and Maui and then translocated to Hawai‘i and Kaua‘i. We detected evidence for only one introduction event from the native range, implying that any adaptive evolution in introduced populations likely utilized the genetic variation present in the founding population. Environmental association tests accounting for population structure identified loci exhibiting signatures of adaptive variation related to predators and landscape characteristics but not nutrient regimes. When paired with high estimates of effective population sizes and detectable population structure, the presence of environment-associated loci supports the role of natural selection in shaping contemporary evolution of Hawaiian guppy populations. Our findings indicate that local adaptation may engender invasion success, particularly in species with life histories that facilitate rapid evolution. Finally, evidence of low gene flow between populations suggests that removal could be an effective approach to control invasive guppies across the Hawaiian archipelago.

59 BASIC BIOLOGICAL SCIENCES↗