Biology subjects

Robinson, K. M.

Publications and source records attributed to Robinson, K. M..

13 recordsLinked to original sources

bioRxiv2026

Division of labor and low temperatures predict geographic variation in thermal tolerance of a North American paper wasp (Mischocyttarus mexicanus cubicola)

The biogeographic study of organismal thermal performance is fundamental to our understanding of how climate drives evolution. However, despite highly social insects being popular models for such studies, biogeographic comparisons of thermal functional traits seldom consider division of labor. Individuals within cooperative societies can operate in different microclimates, exposing different task groups to different selection pressures. Here we present a study of how thermal tolerance limits in a social paper wasp vary broadly across temperate and subtropical climates in eastern North America, testing whether division of labor between foundresses and non-reproductive workers generates adaptive variation in thermal performance within the colony. Cold tolerance rather than heat tolerance varied more predictably with environmental temperatures across latitudes, with temperate populations experiencing bouts of winter cold coma, unlike in subtropical populations. Within colonies, reproductive foundresses were also more cold-tolerant than workers, enabling them to remain mobile at cooler periods of early spring during crucial tasks of nest construction, before workers emerge. Together, these results broaden our understanding of how climate shapes thermal performance on both biogeographic and social scales.

ecology↗

bioRxiv2026

IL-27 Signaling Protects Against Influenza-Associated Pulmonary Aspergillosis Through Inhibition of Type 2 Immunity and Enhanced Antifungal Immunity

Influenza-associated pulmonary aspergillosis (IAPA) is a severe complication of influenza infection associated with substantial mortality. Influenza disrupts pulmonary host defenses and alters innate immune responses, predisposing patients to invasive fungal infection. Interleukin-27 (IL-27) is an immunoregulatory cytokine with context-dependent antiviral and antifungal effects; however, its role during IAPA remains undefined. A mouse model of IAPA was established by infecting wild-type and IL-27 receptor -deficient (Il27ra-/-) mice with influenza A, followed by Aspergillus fumigatus challenge. IL-27 and IL-27R expression were increased during IAPA. Single-cell RNA sequencing identified monocytes as the primary source of IL-27 and T cells as major IL-27r-expressing cells. Il27ra-/- mice exhibited significantly increased pulmonary fungal and influenza viral burden, enhanced type 2 immune responses characterized by elevated IL-4, IL-5, IL-9, IL-13, eosinophils, Th2 cells, pathogenic Th2 cells, and ILC2s. Despite increased eosinophil abundance, eosinophil-mediated conidial killing was impaired in Il27ra-/- mice. IL-27R deficiency also reduced macrophage abundance and impaired macrophage conidial uptake. Conversely, timed administration of rIL-27 enhanced fungal clearance, improved survival, and increased macrophage conidial uptake and augmented eosinophil killing capacity during IAPA. IL-27 signaling is a protective immunoregulatory cytokine during IAPA that limits pathological type 2 inflammation and enhances antifungal effector function of both eosinophils and macrophages. These findings identify IL-27 as a potential therapeutic in IAPA.

immunology↗

bioRxiv2026

Broad remodeling of the pulmonary immune landscape occurs during IAPA with specific functional deficits of neutrophil subsets

BackgroundInfluenza-associated pulmonary aspergillosis (IAPA) is a severe complication of influenza infection associated with prolonged intensive care unit stay and increased mortality. Although impaired antifungal immunity has been implicated in IAPA pathogenesis, the cell type-specific immune mechanisms driving susceptibility remain incompletely understood. We aimed to characterize the pulmonary immune landscape during IAPA using single-cell transcriptomics and functional neutrophil assays. MethodsMale C57BL/6 mice were assigned to naive control, influenza A/PR/8/34 (H1N1) infection, A. fumigatus (ATCC 42202) infection, or IAPA groups. Lung CD45+ immune cells underwent single-cell RNA sequencing with downstream clustering and CellChat ligand-receptor interaction analysis. Differential gene expression analyses were performed across myeloid, lymphoid, and neutrophil populations. Functional neutrophil responses were evaluated using flow cytometry, myeloperoxidase activity assays, and FLARE (fluorescent Aspergillus reporter) conidia to assess fungal conidia uptake and killing. Cross-species validation was performed using gene set enrichment analysis compared with published human IAPA transcriptomic datasets. ResultsIAPA broadly remodeled the pulmonary immune landscape across myeloid, lymphoid, and neutrophil compartments. Myeloid cells showed coordinated suppression of fungal pattern recognition receptors, lysosomal biogenesis programs, and inflammatory signaling. Lymphoid populations exhibited transcriptional signatures of T cell exhaustion and Th17 suppression. Within the neutrophil compartment, we identified two transcriptionally and functionally distinct populations, conventional and inflammatory neutrophils, with divergent antifungal effector capacities. Inflammatory neutrophils showed selective killing defects, while both subsets exhibited impaired phagocytic uptake during IAPA. Murine transcriptomic findings demonstrated strong concordance with immune dysfunction signatures identified in human IAPA. ConclusionIAPA susceptibility arises from coordinated transcriptional dysfunction spanning innate and adaptive immune compartments. Distinct neutrophil subset dysfunction, impaired fungal recognition pathways, and T-cell exhaustion signatures collectively contribute to defective fungal clearance, providing mechanistic insight into IAPA susceptibility and potential therapeutic targets.

immunology↗

bioRxiv2026

Molecular Star Gazing: Development and Validation of an Environmental DNA Assay for the Imperiled Sunflower Sea Star (Pycnopodia helianthoides)

The sunflower sea star (Pycnopodia helianthoides) suffered a catastrophic population decline across its range from 2013 to 2017 due to the devastating Vibrio pectenicida FHCF-3 driven sea star wasting disease (SSWD) pandemic with minimal signs of population recovery. The functional extinction of this apex predator across substantial parts of its range has created a need to identify and track the remaining intact populations. Environmental DNA (eDNA) approaches provide a simple, cost-effective, and non-destructive method for monitoring occurrences, and in some cases abundances, of marine species, consistently outperforming visual occurrence monitoring efforts in sensitivity, speed, and cost. Here, we designed, developed, and validated a P. helianthoides-specific eDNA assay to identify refugia, using both quantitative and digital droplet PCR approaches. We first generated the most comprehensive sea star mitochondrial genome reference database to date (n=93 taxa, n= 15 novel). We then used unikseq and Geneious bioinformatics software to identify the unique nad5 gene region and design a highly specific hydrolysis probe-based PCR assay. We validated the performance of this assay through laboratory, mesocosm, and field testing, demonstrating a highly specific and sensitive assay. In a field application of the new assay across regions in British Columbia, Canada, we found a positive correlation between P. helianthoides eDNA concentrations and biomass density, especially when appropriately accounting for spatiotemporal integration scales (R2=0.67). The eDNA assay provides a rapid and scalable tool for monitoring the sunflower sea star which has been proposed for listing as threatened under the U.S. Endangered Species Act of 1973. Molecular tools like the one presented here enhance management and recovery efforts not only by identification and monitoring of remnant wild populations, but also by helping to assess population level response and recovery following reintroduction efforts.

molecular biology↗

bioRxiv2026

A drought stress-induced MYB transcription factor regulates pavement cell shape in leaves of European aspen (Populus tremula)

The leaf pavement cells of many plant species develop fascinating jigsaw puzzle-like shapes in which neighboring cells interdigitate with each other, providing an ideal model for the study of cell shape acquisition. We analyzed pavement cell shape complexity in a natural population of European aspen (Populus tremula) genotypes and then used a genome-wide association study (GWAS) approach to identify a new candidate gene in cell shape regulation, Potra2n8c18226, encoding the transcription factor MYB305a. We subsequently validated a role for MYB305a in regulating aspen leaf pavement cell shape. We then demonstrated that drought conditions strongly induced MYB305a promoter expression in these cells and provided evidence implying that MYB305a plays a role in simplification of the cell shape in response to drought stress. Finally, we demonstrated negative correlations of pavement cell shape complexity with water-use efficiency, as well as with average precipitation, latitude and longitude of the genotypes original sampling sites in the natural European aspen population. Taken together, our results suggest that climatic variables affect the shape complexity of pavement cells in aspen leaf and provide a first step towards unravelling the molecular mechanisms controlling pavement cell shape acquisition in this species in response to environmental conditions, by implicating the involvement of the transcription factor MY305a.

plant biology↗

bioRxiv2024

Restoration of Type 17 immune signaling is not sufficient for protection during influenza-associated pulmonary aspergillosis

Influenza-associated pulmonary aspergillosis (IAPA) is a severe complication of influenza infection that occurs in critically ill patients and results in higher mortality compared to influenza infection alone. Interleukin-17 (IL-17) and the Type 17 immune signaling pathway cytokine family are recognized for their pivotal role in fostering protective immunity against various pathogens. In this study, we investigate the role of IL-17 and Type 17 immune signaling components during IAPA. Wild-type mice were challenged with influenza A H1N1 (Flu) and then exposed to Aspergillus fumigatus ATCC42202 resting conidia on day 6 post-influenza infection, followed by the quantification of cytokines and chemokines at 48 hours post-fungal infection. Gene and protein expression levels revealed that IL-17 and Type 17 immune cytokines and antimicrobial peptides are downregulated during IAPA compared to mice singularly infected solely with A. fumigatus. Restoration of Type 17 immunity was not sufficient to provide protection against the increased fungal burden observed during IAPA. These findings contrast those observed during post-influenza bacterial super-infection, in which restoration of Type 17 immune signaling protects against exacerbation seen during super-infection. Our study highlights the need for future studies to understand the immune mechanisms that increase susceptibility to fungal infection. ImportanceIAPA significantly elevates the risk of mortality in patients with severe influenza. Type-17 immunity is critical to host defense during fungal infections and, therefore, vital to understand its role during IAPA. The observations in this study reveal that Type 17 immunity is impaired during IAPA, potentially increasing susceptibility to secondary infection with Aspergillus fumigatus. However, restoration of IL-17 signaling alone is not sufficient to reduce fungal burden in our murine IAPA model. These observations differ from those observed in post-influenza bacterial super-infections, suggesting that the mechanisms underlying viral-fungal super-infection are different than those that underly viral-bacterial super-infection. By elucidating the complex interactions between the host immune system, influenza, and A. fumigatus, these findings are vital for developing strategies to enhance immune responses and improve survival rates during IAPA.

immunology↗

bioRxiv2022

Timing Is Everything In Autumn - Coordination Of Senescence Onset By A Transcriptional Program In Response To Environmental And Phytohormone Signals

European aspen (Populus tremula L.) undergoes a coordinated senescence program during autumn; however, it is not known what exactly triggers it. To identify the cellular program leading to senescence, we utilized natural variation among Swedish aspen genotypes in a common garden to study senescence timing and the underlying changes in leaf phytohormone and transcriptome profiles. Apart from the patterns of major transcriptional cascade that was similar between the genotypes and closely associated with cytokinin and auxin metabolite levels and gradually decreasing air temperature during autumn, we detected patterns that consistently preceded or coincided with senescence onset in individual genotypes. Another cascade seemed to respond to short-term changes in weather conditions that re-wired the transcriptional network; the up-regulation of genes related to ethylene and abiotic stress, programmed cell death and translation occurred first in the early-senescing genotypes and later in the late one. Network analyses displayed a connection between the two cascades, metabolic stress and immunity responses mediated by salicylic acid (SA)-signalling pathway that was repressed along with SA levels at senescence onset. We propose that autumn senescence in aspen trees is affected by environmental variation that evokes stress and the timing is fine-tuned by their stress tolerance mechanism. One sentence summarySalicylic acid signalling pathway fine-tunes the timing of senescence onset under challenging environmental conditions in autumn.

plant biology↗

bioRxiv2021

An atlas of the Norway spruce needle seasonal transcriptome

Boreal conifers possess a tremendous ability to survive and remain evergreen during harsh winter conditions and resume growth during summer. This is enabled by coordinated regulation of major cellular functions at the level of gene expression, metabolism, and physiology. Here we present a comprehensive characterization of the annual changes in the global transcriptome of Norway spruce needles as a resource to understand needle development and acclimation processes throughout the year. In young, growing needles (May 15 - June 30), cell walls, organelles etc. were formed, and this developmental program heavily influenced the transcriptome, explained by over represented Gene Ontology (GO) categories. Later changes in gene expression were smaller but four phases were recognized: summer (July-August), autumn (September-October), winter (November-February) and spring (March-April), where over represented GO categories demonstrated how the needles acclimated to the various seasons. Changes in the seasonal global transcriptome profile were accompanied by differential expression of members of the major transcription factor families. We present a tentative model of how cellular activities are regulated over the year in needles of Norway spruce, which demonstrates the value of mining this dataset, accessible in ConGenIE together with advanced visualization tools. Significance statementThe development of Norway spruce needles and their annual cycle of biochemical activities (photosynthesis in the summer, adaptation and survival of the harsh boreal winter) is not well understood. We use deep RNA sequencing to profile the transcriptome over the season, and show how the dataset could be used to give information about "what needles do" over the year, and are here making the dataset available for the scientific community. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=190 SRC="FIGDIR/small/452085v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@1225307org.highwire.dtl.DTLVardef@791821org.highwire.dtl.DTLVardef@1f22dforg.highwire.dtl.DTLVardef@2a8270_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2021

Identification of genetic markers and wood properties that predict wood biorefinery potential in aspen bioenergy feedstock (Populus tremula).

BackgroundWood represents the majority of the biomass on land and constitutes a renewable source of biofuels and other bioproducts. However, wood is recalcitrant to bioconversion, raising a need for feedstock improvement in production of, for instance, biofuels. We investigated the properties of wood that affect bioconversion, as well as the underlying genetics, to help identify superior tree feedstocks for biorefining. ResultsWe recorded 65 wood-related and growth traits in a population of 113 natural aspen genotypes from Sweden. These traits included three growth and field performance traits, 20 traits for wood chemical composition, 17 traits for wood anatomy and structure, and 25 wood saccharification traits as indicators of bioconversion potential. Glucose release after saccharification with acidic pretreatment correlated positively with tree stem height and diameter and the carbohydrate content of the wood, and negatively with the content of lignin and the hemicellulose sugar units. Most of these traits displayed extensive natural variation within the aspen population and high broad-sense heritability, supporting their potential in genetic improvement of feedstocks towards improved bioconversion. Finally, a genome wide association study (GWAS) revealed 13 genetic loci for saccharification yield (on a whole tree biomass basis), with six of them intersecting with associations for either height or stem diameter of the trees. ConclusionsThe simple growth traits of stem height and diameter were identified as good predictors of wood saccharification yield in aspen trees. GWAS elucidated the underlying genetics, revealing putative genetic markers for bioconversion of bioenergy tree feedstocks.

plant biology↗

bioRxiv2021

Adaptive introgression and standing genetic variation, two facilitators of adaptation to high latitudes in European aspen (Populus tremula L.)

Understanding local adaptation in plants from a genomic perspective has become a key research area given the ongoing climate challenge and the concomitant requirement to conserve genetic resources. Perennial plants, such as forest trees, are good models to study local adaptation given their wide geographic distribution, largely outcrossing mating systems and demographic histories. We evaluated signatures of local adaptation in European aspen (Populus tremula) across Europe by means of whole genome re-sequencing of a collection of 411 individual trees. We dissected admixture patterns between aspen lineages and observed a strong genomic mosaicism in Scandinavian trees, evidencing different colonization trajectories into the peninsula from Russia, Central and Western Europe. As a consequence of the secondary contacts between populations after the last glacial maximum (LGM), we detected an adaptive introgression event in a genome region of [~]500kb in chromosome 10, harboring a large-effect locus that has previously been shown to contribute to adaptation to the short growing seasons characteristic of northern Scandinavia. Demographic simulations and ancestry inference suggest an Eastern origin - probably Russian - of the adaptive Nordic allele which nowadays is present in a homozygous state at the north of Scandinavia. The strength of introgression and positive selection signatures in this region is a unique feature in the genome. Furthermore, we detected signals of balancing selection, shared across regional populations, that highlight the importance of standing variation as a primary source of alleles that facilitate local adaptation. Our results therefore emphasize the importance of migration-selection balance underlying the genetic architecture of key adaptive quantitative traits.

evolutionary biology↗

bioRxiv2019

Constructing a high-density linkage map to infer the genomic landscape of recombination rate variation in European Aspen (Populus tremula)

The rate of meiotic recombination is one of the central factors determining levels of linkage disequilibrium and the efficiency of natural selection, and many organisms show a positive correlation between local rates of recombination and levels of nucleotide diversity indicating that linked selection is an important factor determining genome-wide levels of nucleotide diversity. Several methods for estimating recombination rates from segregating polymorphisms in natural populations have recently been developed. These methods have been extensively used in part because they are relatively simple to implement even in many non-model organisms, but also because they potentially offer higher resolution than traditional map-based methods. However, thorough comparisons of LD and map-based estimates of recombination are not readily available in plants. Here we present a new, high-resolution linkage map for Populus tremula and use this to estimate variation in recombination rates across the P. tremula genome. We compare these results to recombination rates estimated based on linkage disequilibrium in a large number of unrelated individuals. We also assess how variation in recombination rates is associated with genomic features, such as gene density, repeat density and methylation levels. We find that recombination rates obtained from the two methods largely agree, although the LD-based method identify a number of genomic regions with very high recombination rates that the map-based method fail to detect. Linkage map and LD-based estimates of recombination rates are positively correlated and show similar correlations with other genomic features, showing that both methods can accurately infer recombination rate variation across the genome.

evolutionary biology↗

bioRxiv2018

Transcriptomic characterization of signaling pathways associated with osteoblastic differentiation of MC-3T3E1 cells

Bone remodeling involves the coordinated actions of osteoclasts, which resorb the calcified bony matrix, and osteoblasts, which refill erosion pits created by osteoclasts to restore skeletal integrity and adapt to changes in mechanical load. Osteoblasts are derived from pluripotent mesenchymal stem cell precursors, which undergo differentiation under the influence of a host of local and environmental cues. To characterize the autocrine/paracrine signaling networks associated with osteoblast maturation and function, we performed gene network analysis using complementary \"agnostic\" DNA microarray and \"targeted\" NanoString nCounter datasets derived from murine MC3T3-E1 cells induced to undergo synchronized osteoblastic differentiation in vitro. Pairwise datasets representing changes in gene expression associated with growth arrest (day 2 to 5 in culture), differentiation (day 5 to 10 in culture), and osteoblast maturation (day 10 to 28 in culture) were analyzed using Ingenuity Systems Pathways Analysis to generate predictions about signaling pathway activity based on the temporal sequence of changes in target gene expression. Our data indicate that some pathways known to be involved in osteoblast differentiation, e.g. Wnt/{beta}-catenin signaling, are most active early in the process, while others, e.g. TGF{beta}/BMP, cytokine/JAK-STAT and TNF/RANKL signaling, increase in activity as differentiation progresses. Collectively, these pathways contribute to the sequential expression of genes involved in the synthesis and mineralization of extracellular matrix. These results provide insight into the temporal coordination and complex interplay between signaling networks controlling gene expression during osteoblast differentiation. A more complete understanding of these processes may aid the discovery of novel methods to promote osteoblast development for the treaent of conditions characterized by low bone mineral density.

cell biology↗

bioRxiv2017

Natural variation at FLOWERING LOCUS T2 mediates local adaptation in a key life history trait in European aspen

BackgroundThe initiation of growth cessation and dormancy represent critical life-history tradeoffs between survival and growth, and have important fitness effects in perennial plants. Such adaptive life history traits often show strong local adaptation along environmental gradients but despite their importance, the genetic architecture of these traits remains poorly understood.\n\nResultsWe integrate whole genome re-sequencing with environmental and phenotypic data from common garden experiments to investigate the genomic basis of local adaptation across a latitudinal gradient in European aspen (Populus tremula). We discover a single genomic region containing the PtFT2 gene that mediates local adaptation in the timing of bud set and that explains 65% of the observed genetic variation in bud set. This locus is the likely target of a recent selective sweep that originated right before or during colonization of northern Scandinavia following the last glaciation. Field and greenhouse experiments confirm that variation in PtFT2 gene expression affect the phenotypic variation in bud set that we observe in wild natural populations.\n\nConclusionsOur results reveal a major effect locus that determine the timing of bud set and that have facilitated rapid adaptation to shorter growing seasons and colder climates in European aspen. The discovery of a single locus explaining a substantial fraction of the variation in a key life history trait is remarkable given that such traits are generally considered to be highly polygenic. These findings provide a dramatic illustration of how loci of large-effect for adaptive traits can arise and be maintained over large geographical scales in natural populations.

evolutionary biology↗