Biology subjects

Lee, S.

Publications and source records attributed to Lee, S..

At least 505 records · Page 28Linked to original sources

bioRxiv2022

Human septins in cells organize as octamer-based filaments mediating actin-membrane anchoring

Septins are cytoskeletal proteins conserved from algae and protists to mammals. Septin knock-out animals have established that septins are essential for animal physiology, but their molecular function remains elusive. A unique feature of septins is their presence as heteromeric complexes that polymerize into filaments in solution and on lipid membranes. Although animal septins associate extensively with actin-based structures in cells, whether actin-decorating septins organize as filaments and if septin organization impacts septin function is not known. Customizing a tripartite split-GFP complementation assay for probing the presence and composition of septin filaments in situ in cells, we show that all septins decorating actin stress fibers are present as filaments whose integrity depends on octameric septin protomers. Atomic force microscopy nanoindentation measurements on cells confirmed that cell stiffness depends on the presence of octamer-containing septin filaments. Super-resolution structured illumination microscopy revealed septin fibers with widths compatible with their organization as paired septin filaments. Nanometer-resolved distance measurements and single-protein tracking further showed that actin-associated septin filaments are membrane-bound and largely immobilized. Finally, reconstitution assays on supported lipid bilayers showed that septin filaments mediate actin-membrane anchoring. We propose that septin organization as octamer-based filaments is essential for septin function in anchoring and stabilizing actin fibers at the plasma membrane.

cell biology↗

bioRxiv2022

Improved pathogen and stress tolerance in tomato mutants of SET domain histone 3 lysine methyltransferases

Histone lysine methylations (HLMs) are implicated in control of gene expression in different eukaryotes. However, the role of HLMs in regulating desirable crop traits and the enzymes involved in these modifications are poorly understood. We studied the functions of tomato histone H3 lysine methyltransferases Set Domain Group 33 (SDG33) and SDG34 in biotic and abiotic stress responses. SDG33 and SDG34 mutants were altered in H3K36 and H3K4 methylations, and expression of genes involved in diverse processes and responses to biotic and abiotic stimuli. The double but not the single mutants show resistance to the fungal pathogen Botrytis cinerea. Interestingly, single mutants were tolerant to drought and the double mutant showed superior tolerance consistent with independent and additive functions. Mutants maintained higher water status during drought and improved recovery and survival after lapse of drought. Notably, diminution of H3K4 and H3K36 trimethylation and expression of negative regulators in challenged plants contributes to stress tolerance of the mutants. Mutations in SDG33 and SDG34 remove predisposition to biotic and abiotic stress by disrupting permissive transcriptional context promoting expression of negative regulatory factors. These allows improvement of stress and pathogen tolerance through modification of histone epigenetic marks.

plant biology↗

bioRxiv2022

Rapid GPR183-mediated recruitment of eosinophils to the lung after Mycobacterium tuberculosis infection

Influx of eosinophils into the lungs is typically associated with type-II responses during allergy, fungal and parasitic infections. However, we previously reported that eosinophils accumulate in lung lesions during type-I inflammatory responses to Mycobacterium tuberculosis (Mtb) in humans, macaques, and mice where they contribute to host resistance. Here we show eosinophils migrate into the lungs of macaques and mice as early as one week after Mtb-exposure. In mice this influx was CCR3 independent and instead required cell-intrinsic expression of the oxysterol-receptor GPR183, which is highly expressed on human and macaque eosinophils. Murine eosinophils interacted directly with bacilli-laden alveolar macrophages, which upregulated the oxysterol-synthesizing enzyme Ch25h, and eosinophil recruitment was impaired in Ch25h deficient mice. Our findings show that eosinophils are among the first cells from circulation to sense and respond to Mtb infection of alveolar macrophages and reveal a novel role for GPR183 in the migration of eosinophils into lung tissue. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/480919v1_ufig1.gif" ALT="Figure 1"> View larger version (105K): org.highwire.dtl.DTLVardef@e8cd29org.highwire.dtl.DTLVardef@1f5769borg.highwire.dtl.DTLVardef@3dce9borg.highwire.dtl.DTLVardef@1c75587_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSIn mice and macaques eosinophils accumulate early in Mtb-infected lungs preceding neutrophils Eosinophils interact with Mtb-infected cells in the alveoli in mice Early pulmonary eosinophil migration occurs independently of CCR3 in mice Early lung migration in mice requires Ch25h and eosinophil-intrinsic GPR183 expression

immunology↗

bioRxiv2022

Decoding Dynamically Shifting States of Parkinson's Disease: Tremor, Bradykinesia, and Effective Motor Control

Parkinsons Disease (PD) is characterized by distinct motor phenomena that are expressed asynchronously. Understanding the neurophysiological correlates of these different motor states could facilitate monitoring of disease progression and allow improved assessments of therapeutic efficacy, as well as enable optimal closed-loop neuromodulation. We examined neural activity in the basal ganglia and cortex of subjects with PD during a quantitative motor task to decode tremor and bradykinesia -- two cardinal motor signs of this disease -- and relatively asymptomatic periods of behavior. Analysis of subcortical and cortical signals revealed that tremor and bradykinesia had distinct, nearly opposite neural signatures, while effective motor control displayed unique, differentiating features. The neurophysiological signatures of these motor states depended on the type of signal recorded as well as the location; cortical decoding accuracy generally outperformed subcortical decoding, while tremor and bradykinesia were better decoded from different portions of the subthalamic nucleus (STN). These results provide a roadmap to leverage real-time neurophysiology to understand and treat PD. One Sentence SummaryMotor signs of Parkinsons disease such as tremor and bradykinesia can be independently decoded from subthalamic and cortical recordings.

neuroscience↗

bioRxiv2022

Transfer Learning for Cognitive Reserve Quantification

Cognitive reserve (CR) has been introduced to explain individual differences in susceptibility to cognitive or functional impairment in the presence of age or pathology. We developed a deep learning model to quantify the CR as residual variance in memory performance using the structural MRI data from a lifespan healthy cohort. The generalizability of the sMRI-based deep learning model was tested in two independent healthy and Alzheimers cohorts using transfer learning framework. Structural MRIs were collected from three cohorts: 495 healthy adults (initially aged 20-80) from RANN, 620 healthy participants (age 36-100) from lifespan Human Connectome Project Aging (HCPA), and 941 subjects from Alzheimers Disease Neuroimaging Initiative (ADNI). Region of interest (ROI)-specific cortical thickness and volume measures were extracted using the Desikan-Killiany Atlas. Cognitive reserve was quantified by residuals which subtract the predicted memory from the true memory. Cascade neural network (CNN) models were used to train RANN dataset for memory prediction. Transfer learning was applied to transfer the T1 imaging-based model from source domain (using RANN) to the target domain (HCPA or ADNI). The CNN model trained on the RANN dataset exhibited strong linear correlation between true and predicted memory based on the chosen T1 cortical thickness and volume predictors. In addition, the model generated from healthy lifespan data (RANN) was able to generalize to an independent healthy lifespan data (HCPA) and older demented participants (ADNI) across different scanner types. The estimated CR was correlated with CR proxies such education and IQ across all three datasets. The current findings suggest that the transfer learning approach is an effective way to generalize the residual-based CR estimation. It is applicable to various diseases and may flexibly incorporate different imaging modalities such as fMRI and PET, making it a promising tool for scientific and clinical purposes. HighlightO_LIQuantification of cognitive reserve using brain measures for pre-symptomatic Alzheimers patients can be estimated by leveraging lifespan data. C_LIO_LIMulti-center, multi-scanner, multi-sequence can affect the performance of the quantification. C_LIO_LILeveraging lifespan data from a single site can improve the performance. C_LIO_LITransfer learning allows the pre-trained network to successfully reconstruct the dataset acquired from different domains or age groups. C_LI

bioinformatics↗

bioRxiv2022

Existence of blood circulating immune-cell clusters (CICs) comprising antigen-presenting cells and B cells

Cell-to-cell physical interactions are involved in almost every physiological processes in multicellular organisms. Although the dynamics of these interactions could be highly diverse and complex in many circumstances, certain cell-to-cell interactions among immune cells have been well studied due importance in understanding disease pathogenesis and immune therapy development1. Dendritic cells (DCs) and B cells are directly involved in adaptive immune response against pathogens. Interaction mechanism between these two celltypes is well-known to occur in germinal centers either indirectly via helper T (Th) cells or directly via cell contact. However, there are animal in vitro and in vivo evidence that such direct DC-to-B cell contact can occur outside germinal centers like in peripheral blood or collagen matrix and display antiviral immune-related activity2,3. Here, we provide evidence that certain types of antigen presenting cells (APCs) can form robust cell clusters with B cells and circulate in blood. From healthy human blood immune single cell RNA-seq datasets, we detected APC subpopulations (0.34{+/-}0.19% of total PBMCs) that were also enriched with well-known naive B cell markers. We visually observed DC:B doublets and multiplets ([~]0.69% of total live PBMCs) in wildtype mouse blood using flow cytometry and microscopic imaging, thus proving the existence of circulating immune-cell clusters (CICs) composed of APCs and B cells. BCR repertoire of these healthy mouse CICs were similar to circulating B cells. Noticeably, frequency of these APC:B CICs were higher COVID-19 patients than healthy donors and their B cell subtype composition (e.g. naive, plasmablast, IgM+, IgG+) varied with disease severity.

immunology↗

bioRxiv2022

SARS-CoV-2 Infection of Microglia Elicits Pro-inflammatory Activation and Apoptotic Cell Death

Accumulating evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes various neurological symptoms in coronavirus disease 2019 (COVID-19) patients. The most dominant immune cells in the brain are microglia. Yet, the relationship between neurological manifestations, neuroinflammation, and host immune response of microglia to SARS-CoV-2 has not been well characterized. Here, we report that SARS-CoV-2 can directly infect human microglia, eliciting M1-like pro-inflammatory responses, followed by cytopathic effects. Specifically, SARS-CoV-2 infected human microglial clone 3 (HMC3), leading to inflammatory activation and cell death. RNA-seq analysis also revealed that ER stress and immune responses were induced in the early and apoptotic processes in the late phase of viral infection. SARS-CoV-2-infected HMC3 showed the M1 phenotype and produced pro-inflammatory cytokines such as interleukin (IL)-1{beta}, IL-6, and tumour necrosis factor (TNF-), but not the anti-inflammatory cytokine IL-10. After this pro-inflammatory activation, SARS-CoV-2 infection promoted both intrinsic and extrinsic death receptor-mediated apoptosis in HMC3. Using K18-hACE2 transgenic mice, murine microglia were also infected by intranasal inoculation of SARS-CoV-2. This infection induced the acute production of pro-inflammatory microglial IL-6 and TNF- and provoked a chronic loss of microglia. Our findings suggest that microglia are potential mediators of SARS-CoV-2-induced neurological problems and, consequently, can be targets of therapeutic strategies against neurological diseases in COVID-19 patients. IMPORTANCERecent studies reported neurological manifestations and complications in COVID-19 patients, which are associated with neuroinflammation. As microglia are the dominant immune cells in brains, it needs to be elucidate the relationship between neuroinflammation and host immune response of microglia to SARS-CoV-2. Here, we suggest that SARS-CoV-2 can directly infect human microglia with cytopathic effect (CPE) using human microglial clone 3 (HMC3). The infected microglia were promoted to pro-inflammatory activation following apoptotic cell death. This pro-inflammatory activation was accompanied by the high production of pro-inflammatory cytokines, and led to neurotoxic-M1 phenotype polarization. In vivo, murine microglia were infected and produced pro-inflammatory cytokines and provoked a chronic loss using K18-hACE2 mice. Thus, our data present that SARS-CoV-2-infected microglia are potential mediators of neurological problems in COVID-19 patients. In addition, HMC3 cells are susceptible to SARS-CoV-2 and exhibit the CPE, which can be further used to investigate cellular and molecular mechanisms of neuroinflammation reported in COVID-19 patients.

microbiology↗

bioRxiv2022

Signaling modality within gp130 receptor enhances tissue regeneration

Adult mammals are incapable of multi-tissue regeneration and augmentation of this potential may drastically shift current therapeutic paradigms. Here, we found that a common co-receptor of IL-6 cytokines, glycoprotein 130 (gp130), serves as a major nexus integrating various context-specific signaling inputs to either promote regenerative outcomes or aggravate disease progression. Via genetic and pharmacological experiments in vitro and in vivo, we demonstrated that a signaling tyrosine 814 (Y814) within gp130 serves as a major cellular stress sensor. Mice with constitutively inactivated Y814 (F814) exhibit regenerative, not reparative, responses after wounding in skin and anti-degenerative responses in the synovial joint. In addition, pharmacological inhibition of gp130 Y814 results in regeneration of multiple tissues in several species as well as disease modification in animal models of osteoarthritis. Our study characterizes a novel molecular mechanism that, if selectively manipulated, enhances the intrinsic regenerative capacity while preventing pathological outcomes in injury and disease. SummaryGp130 Y814 signaling module serves as a cellular stress sensor responsible for hindering tissue regeneration while triggering pathological outcomes after injury.

molecular biology↗

bioRxiv2021

Unsupervised genome-wide cluster analysis: nucleotide sequences of the omicron variant of SARS-CoV-2 are similar to sequences from early 2020

The GISAID database contains more than 1,000,000 SARS-CoV-2 genomes, including sequences of the recently discovered SARS-CoV-2 omicron variant and of prior SARS-CoV-2 strains that have been collected from patients around the world since the beginning of the pandemic. We applied unsupervised cluster analysis to the SARS-CoV-2 genomes, assessing their similarity at a genome-wide level based on the Jaccard index and principal component analysis. Our analysis results show that the omicron variant sequences are most similar to sequences that have been submitted early in the pandemic around January 2020. Furthermore, the omicron variants in GISAID are spread across the entire range of the first principal component, suggesting that the strain has been in circulation for some time. This observation supports a long-term infection hypothesis as the omicron strain origin.

bioinformatics↗

bioRxiv2021

ABCnet : Self-Attention based Atom, Bond Message Passing Network for Predicting Drug-Target Interaction

Drug-target interaction (DTI) is a methodology for predicting the binding affinity between a compound and a target protein, and a key technology in the derivation of candidate substances in drug discovery. As DTI experiments have progressed for a long time, a substantial volume of chemical, biomedical, and pharmaceutical data have accumulated. This accumulation of data has occurred contemporaneously with the advent of the field of big data, and data-based machine learning methods could significantly reduce the time and cost of drug development. In particular, the deep learning method shows potential when applied to the fields of vision and speech recognition, and studies to apply deep learning to various other fields have emerged. Research applying deep learning is underway in drug development, and among various deep learning models, a graph-based model that can effectively learn molecular structures has received more attention as the SOTA in experimental results were achieved. Our study focused on molecular structure information among graph-based models in message passing neural networks. In this paper, we propose a self-attention-based bond and atom message passing neural network which predicts DTI by extracting molecular features through a graph model using an attention mechanism. Model validation experiments were performed after defining binding affinity as a regression and classification problem: binary classification to predict the presence or absence of binding to the drug-target, and regression to predict binding affinity to the drug-target. Classification was performed with BindingDB, and regression was performed with the DAVIS dataset. In the classification problem, ABCnet showed higher performance than MPNN, as it does in the existing study, and in regression, the potential of ABCnet was checked compared to that of SOTA. According to experiments, for Binary classification ABCnet have an average performance improvement of 1% for higher performance on DTI task than other MPNN and for regresssion ABCnet have CI with an average 0.01 to 0.02 performance degradation compared to SOTA. https://www.overleaf.com/project/618a05533676801d8f68ccf6

bioinformatics↗

bioRxiv2021

Simultaneous quantification of ankle, muscle, and tendon impedance in humans

ObjectiveRegulating the impedance of our joints is essential for the effective control of posture and movement. The impedance of a joint is governed mainly by the mechanical properties of the muscle-tendon units spanning it. Many studies have quantified the net impedance of joints but not the specific contributions from the muscles and tendons. The inability to quantify both muscle and tendon impedance limits the ability to determine the causes underlying altered movement control associated with aging, neuromuscular injury, and other conditions that have different effects on muscle and tendon properties. Therefore, we developed a technique to quantify joint, muscle, and tendon impedance simultaneously and evaluated this technique at the human ankle. MethodsWe used a single degree of freedom actuator to deliver pseudorandom rotations to the ankle while measuring the corresponding torques. We simultaneously measured the displacement of the medial gastrocnemius muscle-tendon junction with B-mode ultrasound. From these experimental measurements, we were able to estimate ankle, muscle, and tendon impedance using non-parametric system identification. ResultsWe validated our estimates by comparing them to previously reported muscle and tendon stiffness, the position-dependent component of impedance, to demonstrate that our technique generates reliable estimates of these properties. ConclusionOur approach can be used to clarify the respective contributions from the muscle and tendon to the net mechanics of a joint. SignificanceThis is a critical step forward in the ultimate goal of understanding how muscles and tendons govern ankle impedance during posture and movement.

bioengineering↗

bioRxiv2021

Ribosome changes elicit non-canonical translation for chemosurvival in G0 leukemic cells

Quiescent leukemic cells survive chemotherapy, with translation changes. Our data reveal that FXR1, a protein amplified in several aggressive cancers, increases in quiescent and chemo- treated leukemic cells, and promotes chemosurvival. This suggests undiscovered roles for this RNA- and ribosome-associated protein in chemosurvival. FXR1 depletion decreases translation and ribosome subunits, with altered rRNAs, snoRNAs, and ribosomal proteins (RPs). We find that FXR1 binds factors that promote ribosome gene transcription and bind snoRNAs. Ribosome changes increased in FXR1-overexpressing cells, including increased snoRNAs and RPLP0/uL10, activate eIF2 kinases. Accordingly, phospho-eIF2 increases, enabling non- canonical translation of survival and immune regulators in FXR1-overexpressing cells. Overriding these with inhibitors reduces chemosurvival. Thus, increased FXR1 in quiescent or chemo-treated leukemic cells, alters ribosomes that trigger stress signals to re-direct translation for chemosurvival. One Sentence SummaryFXR1 alters ribosomes in G0, which induce stress signals to elicit noncanonical translation for AML drug and immune survival.

molecular biology↗

bioRxiv2021

A robust and adaptive framework for interaction testing in quantitative traits between multiple genetic loci and exposure variables

The identification and understanding of gene-environment interactions can provide insights into the pathways and mechanisms underlying complex diseases. However, testing for gene-environment interaction remains a challenge since statistical power is often limited, the specification of environmental effects is nontrivial, and such misspecifications can lead to false positive findings. To address the lack of statistical power, recent methods aim to identify interactions on an aggregated level using, for example, polygenic risk scores. While this strategy increases power to detect interactions, identifying contributing key genes and pathways is difficult based on these global results. Here, we propose RITSS (Robust Interaction Testing using Sample Splitting), a gene-environment interaction testing framework for quantitative traits that is based on sample splitting and robust test statistics. RITSS can incorporate multiple genetic variants and/or multiple environmental factors. Using sample splitting, a screening step enables the selection and combination of potential interactions into scores with improved interpretability, based on the users unrestricted choices for statistical/machine learning approaches. In the testing step, the application of robust test statistics minimizes the susceptibility of the results to main effect misspecifications. Using extensive simulation studies, we demonstrate that RITSS controls the type 1 error rate in a wide range of scenarios. In an application to lung function phenotypes and human height in the UK Biobank, RITSS identified genome-wide significant interactions with subcomponents of genetic risk scores. While the contributing single variant interactions are moderate, our analysis results indicate interesting interaction patterns that result in strong aggregated signals that provide further insights into gene-environment interaction mechanisms.

bioinformatics↗

bioRxiv2021

De Novo Pyrimidine Synthesis is a Targetable Vulnerability in IDH Mutant Glioma

Mutations affecting isocitrate dehydrogenase (IDH) enzymes are prevalent in glioma, leukemia, and other cancers. Although mutant IDH inhibitors are effective against leukemia, they appear less active in aggressive glioma, underscoring the need for alternative treatment strategies. Through a chemical synthetic lethality screen, we discovered that IDH1 mutant glioma cells are hypersensitive to drugs targeting enzymes in the de novo pyrimidine nucleotide synthesis pathway, including dihydroorotate dehydrogenase (DHODH). We developed a genetically engineered mouse model of mutant IDH1-driven astrocytoma and used it and multiple patient-derived models to show that the brain-penetrant DHODH inhibitor BAY 2402234 displays monotherapy efficacy against IDH mutant gliomas. Mechanistically, this vulnerability selectively applies to de novo pyrimidine, but not purine, synthesis because glioma cells engage disparate programs to produce these nucleotide species and because IDH oncogenes increase DNA damage upon nucleotide pool imbalance. Our work outlines a tumor-selective, biomarker-guided therapeutic strategy that is poised for clinical translation.

cancer biology↗

bioRxiv2021

LRRC15 is an inhibitory receptor blocking SARS-CoV-2 spike-mediated entry in trans

SARS-CoV-2 infection is mediated by the entry receptor ACE2. Although attachment factors and co-receptors facilitating entry are extensively studied, cellular entry factors inhibiting viral entry are largely unknown. Using a surfaceome CRISPR activation screen, we identified human LRRC15 as an inhibitory receptor for SARS-CoV-2 entry. LRRC15 directly binds to the receptor-binding domain (RBD) of spike protein with a moderate affinity and inhibits spike-mediated entry. Analysis of human lung single cell RNA sequencing dataset reveals that expression of LRRC15 is primarily detected in fibroblasts and particularly enriched in pathological fibroblasts in COVID-19 patients. ACE2 and LRRC15 are not co-expressed in the same cell types in the lung. Strikingly, expression of LRRC15 in ACE2-negative cells blocks spike-mediated viral entry in ACE2+ cell in trans, suggesting a protective role of LRRC15 in a physiological context. Therefore, LRRC15 represents an inhibitory receptor for SARS-CoV-2 regulating viral entry in trans.

microbiology↗

bioRxiv2021

Genome assembly of the JD17 soybean provides a new reference genome for Comparative genomics

Cultivated soybean (Glycine max) is an important source for protein and oil. Many elite cultivars with different traits have been developed for different conditions. Each soybean strain has its own genetic diversity, and the availability of more high-quality soybean genomes can enhance comparative genomic analysis for identifying genetic underpinnings for its unique traits. In this study, we constructed a high-quality de novo assembly of an elite soybean cultivar Jidou 17 (JD17) with chromsome contiguity and high accuracy. We annotated 52,840 gene models and reconstructed 74,054 high-quality full-length transcripts. We performed a genome-wide comparative analysis based on the reference genome of JD17 with three published soybeans (WM82, ZH13 and W05), which identified five large inversions and two large translocations specific to JD17, 20,984 - 46,912 PAVs spanning 13.1 - 46.9 Mb in size, and 5 - 53 large PAV clusters larger than 500kb. 1,695,741 - 3,664,629 SNPs and 446,689 - 800,489 Indels were identified and annotated between JD17 and them. Symbiotic nitrogen fixation (SNF) genes were identified and the effects from these variants were further evaluated. It was found that the coding sequences of 9 nitrogen fixation-related genes were greatly affected. The high-quality genome assembly of JD17 can serve as a valuable reference for soybean functional genomics research.

genomics↗

bioRxiv2021

Suppressed prefrontal neuronal firing variability and impaired social representation in IRSp53-mutant mice

Social deficit is a major feature of neuropsychiatric disorders, including autism spectrum disorders, schizophrenia, and attention-deficit/hyperactivity disorder, but its neural mechanisms remain unclear. Here, we examined neuronal discharge characteristics in the medial prefrontal cortex (mPFC) of IRSp53-mutant mice, which show social deficits, during social approach. IRSp53-mutant excitatory mPFC neurons displayed an increase in baseline neuronal firing and decreases in variability and dynamic range of firing rates and burst firing during social and non-social target approaches compared to wild-type controls. As a consequence, their firing activity was less differential between social and non-social targets. In addition, there was a decrease in the proportion of excitatory mPFC neurons encoding social information but not that of those encoding non-social information. These results suggest that insufficient neuronal activity dynamics may underlie impaired cortical encoding of social information and social behaviors in IRSp53-mutant mice.

neuroscience↗

bioRxiv2021

A two-phase plant-soil feedback experiment to explore biotic influences on Phragmites australis invasion in North American wetlands

Plants can cultivate soil microbial communities that affect subsequent plant growth through a plant-soil feedback (PSF). Strong evidence indicates that PSFs can mediate the invasive success of exotic upland plants, but many of the most invasive plants occur in wetlands. In North America, the rapid spread of European Phragmites australis cannot be attributed to innate physiological advantages, thus PSFs may mediate invasion. Here we apply a two-phase fully-factorial plant-soil feedback design in which field-derived soil inocula were conditioned using saltmarsh plants and then were added to sterile soil mesocosms and planted with each plant type. This design allowed us to assess complete soil biota effects on intraspecific PSFs between native and introduced P. australis as well as heterospecific feedbacks between P. australis and the native wetland grass, Spartina patens. Our results demonstrate that native P. australis experienced negative conspecific feedbacks while introduced P. australis experienced neutral conspecific feedbacks. Interestingly, S. patens soil inocula inhibited growth in both lineages of P. australis while introduced and native P. australis inocula promoted the growth of S. patens suggestive of biotic resistance against P. australis invasion by S. patens. Our findings suggest that PSFs are not directly promoting the invasion of introduced P. australis in North America. Furthermore, native plants like S. patens seem to exhibit soil microbe mediated biotic resistance to invasion which highlights the importance of disturbance in mediating introduced P. australis invasion.

ecology↗