Biology subjects

Jones, J.

Publications and source records attributed to Jones, J..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Identification of post-transcriptional modifications in nucleic acid sequences using propose-designed molecular beacons

Post-transcriptional RNA modifications (PTxMs) present in small RNA species, specifically circulating extracellular RNAs, were recently identified as clinically relevant readouts, often more indicative of disease severity than the classical "up and down" changes in their copy number alone. While identification of PTxMs requires multiple and complex sample preparation steps, microgram-range amounts of RNA, followed by expensive and protracted bioinformatics analyses, the clinically relevant information is usually a yes/no for a particular genetic variant(s), and an up/down answer for relevant biomarkers. We have previously shown that molecular beacons (MBs) can identify specific nucleic acid sequences with picomolar sensitivity and single nucleotide specificity by exploiting the target-dependent change in their electrophoretic mobility profile. We now present a method for direct identification of miRNAs and isomiRs in cells and extracellular vesicles using gel electrophoresis, without the need for RNA isolation and purification. The detection is based on discreet changes in the hydrodynamic surface profile, the overall size, charge and charge distribution of the MB-target hybrid. Furthermore, using an RNA tertiary structure prediction algorithm (iFoldRNA) and a custom molecular dynamics simulation (DMD), we designed modified MBs specific for m6A-modified nucleotides in target RNA sequences. The sample preparation method coupled to the software package affords the design of specific MBs and sensitive, multiplex-type detection of targets in a wide variety of biofluids and cells, in a simple mix and read approach.

molecular biology↗

bioRxiv2023

Stimulator of interferon genes is required for Toll-Like Receptor-8 induced interferon response

The innate immune system is equipped with multiple receptors to detect microbial nucleic acids and induce type I interferon (IFN) to restrict viral replication. When dysregulated these receptor pathways induce inflammation in response to host nucleic acids and promote development and persistence of autoimmune diseases like Systemic Lupus Erythematosus (SLE). IFN production is regulated by the Interferon Regulatory Factor (IRF) transcription factor family of proteins that function downstream of several innate immune receptors such as Toll-like receptors (TLRs) and Stimulator of Interferon Genes (STING). Although both TLRs and STING activate the same downstream molecules, the pathway by which TLRs and STING activate IFN response are thought to be independent. Here we show that STING plays a previously undescribed role in human TLR8 signaling. Stimulation with the TLR8 ligands induced IFN secretion in primary human monocytes, and inhibition of STING reduced IFN secretion from primary monocytes from 8 healthy donors. We demonstrate that TLR8-induced IRF activity was reduced by STING inhibitors. Moreover, TLR8-induced IRF activity was blocked by inhibition or loss of IKK{varepsilon}, but not TBK1. Bulk RNA transcriptomic analysis supported a model where TLR8 induces transcriptional responses associated with SLE that can be downregulated by inhibition of STING. These data demonstrate that STING is required for full TLR8-to-IRF signaling and provide evidence for a new framework of crosstalk between cytosolic and endosomal innate immune receptors, which could be leveraged to treat IFN driven autoimmune diseases. BackgroundHigh levels of type I interferon (IFN) is characteristic of multiple autoimmune diseases, and while TLR8 is associated with autoimmune disease and IFN production, the mechanisms of TLR8-induced IFN production are not fully understood. ResultsSTING is phosphorylated following TLR8 signaling, which is selectively required for the IRF arm of TLR8 signaling and for TLR8-induced IFN production in primary human monocytes. ConclusionSTING plays a previously unappreciated role in TLR8-induced IFN production SignificanceNucleic acid-sensing TLRs contribute to development and progression of autoimmune disease including interferonopathies, and we show a novel role for STING in TLR-induced IFN production that could be a therapeutic target.

immunology↗

bioRxiv2023

Keystone pathobionts associated with colorectal cancer promote oncogenic reprograming

Fusobacterium nucleatum (Fn) and enterotoxigenic Bacteroides fragilis (ETBF) are two pathobionts consistently enriched in the gut microbiomes of patients with colorectal cancer (CRC) compared to healthy counterparts and frequently observed for their direct association within tumors. Although several molecular mechanisms have been identified that directly link these organisms to features of CRC in specific cell types, their specific effects on the epithelium and local immune compartment are not well-understood. To fill this gap, we leveraged single-cell RNA sequencing (scRNA-seq) on wildtype mice and mouse model of CRC. We find that Fn and ETBF exacerbate cancer-like transcriptional phenotypes in transit-amplifying and mature enterocytes in a mouse model of CRC. We also observed increased T cells in the pathobiont-exposed mice, but these pathobiont-specific differences observed in wildtype mice were abrogated in the mouse model of CRC. Although there are similarities in the responses provoked by each organism, we find pathobiont-specific effects in Myc-signaling and fatty acid metabolism. These findings support a role for Fn and ETBF in potentiating tumorigenesis via the induction of a cancer stem cell-like transit-amplifying and enterocyte population and the disruption of CTL cytotoxic function.

microbiology↗

bioRxiv2022

Neurobehavioral precursors of compulsive cocaine-seeking in dual fronto-striatal circuits

Only some individuals using drugs recreationally eventually become addicted, and persist in drug seeking and taking despite adverse consequences. The neurobehavioral determinants of this individual vulnerability have not been fully elucidated. We report that in drug naive rats the future tendency to develop compulsive cocaine seeking is characterised by behavioral stickiness-related functional hypoconnectivity between the prefrontal cortex and posterior dorsomedial striatum in combination with impulsivity-related structural alterations in the infralimbic cortex, anterior insula and nucleus accumbens. These findings show that the vulnerability to develop compulsive cocaine seeking behavior stems from pre-existing structural or functional changes in two distinct cortico-striatal systems that underlie deficits in impulse control and goal-directed behavior.

neuroscience↗

bioRxiv2022

Structural analysis of cancer-relevant TCR-CD3 and peptide-MHC complexes by cryoEM

The recognition of antigenic peptide-MHC (pMHC) molecules by T-cell receptors (TCR) initiates the T-cell mediated immune response. Structural characterization is key for understanding the specificity of TCR-pMHC interactions and informing the development of therapeutics. Despite the rapid rise of single particle cryoelectron microscopy (cryoEM), x-ray crystallography has remained the preferred method for structure determination of TCR-pMHC complexes. Here, we report cryoEM structures of two distinct full-length /{beta} TCR-CD3 complexes bound to their pMHC ligand, the cancer-testis antigen HLA-A2/MAGEA4 (230-239). We also determined cryoEM structures of pMHCs containing MAGEA4 (230-239) peptide and the closely related MAGEA8 (232-241) peptide in the absence of TCR, which provided a structural explanation for the MAGEA4 preference displayed by the TCRs. These findings provide insights into the TCR recognition of a clinically relevant cancer antigen and demonstrate the utility of cryoEM for high-resolution structural analysis of TCR-pMHC interactions.

biochemistry↗

bioRxiv2022

StandardRat: A multi-center consensus protocol to enhance functional connectivity specificity in the rat brain

Task-free functional connectivity in animal models provides an experimental framework to examine connectivity phenomena under controlled conditions and allows comparison with invasive or terminal procedures. To date, animal acquisitions are performed with varying protocols and analyses that hamper result comparison and integration. We introduce StandardRat, a consensus rat functional MRI acquisition protocol tested across 20 centers. To develop this protocol with optimized acquisition and processing parameters, we initially aggregated 65 functional imaging datasets acquired in rats from 46 centers. We developed a reproducible pipeline for the analysis of rat data acquired with diverse protocols and determined experimental and processing parameters associated with a more robust functional connectivity detection. We show that the standardized protocol enhances biologically plausible functional connectivity patterns, relative to pre-existing acquisitions. The protocol and processing pipeline described here are openly shared with the neuroimaging community to promote interoperability and cooperation towards tackling the most important challenges in neuroscience.

neuroscience↗

bioRxiv2022

A Novel Restraint Device to Improve Safety and Efficacy of Blood Collection During Non-Terminal Sampling of Bats

There are a variety of blood collection techniques described in the literature for unanesthetized bats, which typically require multiple sharps (e.g., needles, lancets, etc.), competent animal handling for prolonged periods, and usually involve two individuals. With the challenges inherent to non-terminal sampling of blood from bats, as well as the growing need for the use of this technique across multiple disciplines and industries, an improved blood collection method is needed. We report the creation of a bat restraint device specifically designed for a single individual to safely collect blood from anesthetized or non-anesthetized bats. The utility of this restraint device is multifaceted, serving as a safety measure for both animal and handler, as well as increasing the efficiency of blood collection. The restraint device was tested during two laboratory bat studies, Afterwards, the users of the restraint device were provided with a 10-question survey questionnaire to record their opinions on its usage. In total 80% of responses were considered positive, 15% considered neutral, and 5% considered negative. Survey questions that all participants responded to positively when in comparison to the traditional method of blood collection from bats include "easier to perform", "safer to bats", and "safer to the individual". While using the restraint devices during the laboratory studies, no needle sticks, bites, or scratches to laboratorians occurred, and no observable health issues or complication due to blood collection in the bats bled using the restraint devices.

zoology↗

bioRxiv2022

Oncogenic c-Myc activity increases tolerance to proteotoxic and genotoxic stress through regulation of HSF1

Oncogenes, such as c-Myc, enhance growth and proliferative signaling to promote continuous cell cycle divisions, the hallmark of cancer. The inadvertent consequence of this is an increase in cellular stresses. However, whether and how oncogenes can directly contribute to cellular stress tolerance, and how much cancer cells rely on these mechanisms for survival, remains poorly understood. Here we show that c-Mycdependent proteotoxic stress contributes to the generation of genotoxic stress. We reveal an important role for the transcription factor Heat Shock Factor 1 (HSF1) in the tolerance to both these c-Myc-induced stresses. c-Myc upregulates HSF1 directly, by activating its expression, and indirectly, via c-Mycdependent proteotoxic stress activation. In addition to relieving c-Myc-induced proteotoxic and genotoxic stress, HSF1 also enables DNA damage response signalling through{gamma} H2AX. Consequently, acute depletion of HSF1 significantly increases c-Myc-driven genome instability and decreases cell viability. Our results establish that c-Myc-dependent regulation of HSF1 ensures that proteotoxic and genotoxic stress, resulting from c-Myc-induced enhanced growth and proliferation, are compatible with cell survival.

cancer biology↗

bioRxiv2022

A Split-GAL4 screen identifies novel sleep-promoting neurons in the Ventral Nerve Cord of Drosophila

As in the mammalian system, sleep in Drosophila is regulated by multiple brain regions. Among them, neurons projecting to the dorsal Fan-Shaped Body (dFB) have been intensively studied and the data suggest they play a critical role in sleep regulation. The 23E10-GAL4 driver is the most widely used tool to label and manipulate dFB neurons. Multiple studies have reported that activation of 23E10-GAL4 neurons promotes sleep. However, anatomical analyses revealed that 23E10-GAL4 labels 23-30 dFB neurons in the Drosophila brain and many non-dFB neurons in the brain and in the Ventral Nerve Cord (VNC), the fly equivalent of the spinal cord. To better understand the role of individual dFB neurons in sleep regulation, we undertook a Split-GAL4 screen to gain access to subsets of 23E10-GAL4 expressing cells. In this study, we report the discovery of two VNC cholinergic sleep-promoting neurons labeled by the 23E10-GAL4 driver.

neuroscience↗

bioRxiv2022

Bio-inspired artificial printed bioelectronic cardio-3D-cellular constructs

Bioelectronics is a growing field where novel smart materials are required to interface biology with electronic components. Conductive hydrogels have recently emerged as a promising material for biosensing/actuating applications as they can provide a wet, nanostructured and electrically conductive environment, minimising the mismatch between biological and electronic systems. In this work, we propose a strategy to develop conductive bioinks compatible with the freeform reversible embedding of suspended hydrogels (FRESH) extrusion bioprinting method. These bioinks are based on decellularized extracellular matrix (dECM), extracted from three different tissues (small intestine submucosa, liver and bone) and were characterised. 3D structures were manufactured containing human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), exhibiting cell viabilities >80%. Multi-walled carbon nanotubes (MWCNTs) were selected as an additional component of the bioinks. The addition of the MWCNTs enhanced the conductive features of the hydrogels and the morphology of the dECM fibres. Electrical stimulation (ES) through alternating currents was applied to hPSC-CMs encapsulated in 3D structures manufactured with the previous material and our results indicated two main findings: (1) in the absence of external ES, the conductive properties of the materials can improve the contractile behaviour of the hPSC-CMs and (2) this effect is significantly enhanced under the application of external ES. Genetic markers analysed showed a trend towards a more mature state of the cells evaluated by the TNNI3/TNNI1 ratio, with upregulated SERCA2 and RYR2 calcium handling proteins when compared to controls and downregulation of calcium channels involved in the generation of pacemaking currents (CACNA1H). These results demonstrate the potential of our strategy to manufacture conductive hydrogels in complex geometries for bioactuating purposes. However, further development of the 3D bioprinting techniques is required to achieve higher control over the nano- and microarchitectures of the structures to improve their biomimicry.

bioengineering↗

bioRxiv2022

Intestinal Bacteroides Modulates Systemic Inflammation and the Microbial Ecology in a Mouse Model of CF: Evidence for Propionate and other Short Chain Fatty Acids Reducing Systemic Inflammatory Cytokines

Persons with cystic fibrosis, starting in early life, have intestinal microbiome dysbiosis characterized in part by a decreased relative abundance of the genus Bacteroides. Bacteroides is a major producer of the intestinal short chain fatty acid (SCFA) propionate. We demonstrate here that CFTR-/- Caco-2 intestinal epithelial cells are responsive to the anti-inflammatory effects of propionate. Furthermore, Bacteroides isolates inhibit the IL-1{beta}-induced inflammatory response of CFTR-/- Caco-2 intestinal epithelial cells and do so in a propionate-dependent manner. Bacteroides isolates also produce low levels of butyrate; this SCFA is positively correlated with inhibition of the inflammatory response. Finally, the introduction of Bacteroides-supplemented stool from infants with CF into the gut of CftrF508del mice results in an increase in propionate in the stool as well as the reduction in several systemic pro-inflammatory cytokines. Bacteroides supplementation also reduced the fecal relative abundance of E. coli, indicating a potential interaction between these two microbes, consistent with previous clinical studies. Together, our data indicate the important role of Bacteroides and Bacteroides-derived propionate in the context of the developing microbiome in infants and children with CF, which could help explain the observed gut-lung axis in CF.

microbiology↗

bioRxiv2021

Differential neutralization and inhibition of SARS-CoV-2 variants by antibodies elicited by COVID-19 mRNA vaccines

IntroductoryThe evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the emergence of many new variant lineages that have exacerbated the COVID-19 pandemic. Some of those variants were designated as variants of concern/interest (VOC/VOI) by national or international authorities based on many factors including their potential impact on vaccines. To ascertain and rank the risk of VOCs and VOIs, we analyzed their ability to escape from vaccine-induced antibodies. The variants showed differential reductions in neutralization and replication titers by post-vaccination sera. Although the Omicron variant showed the most escape from neutralization, sera collected after a third dose of vaccine (booster sera) retained moderate neutralizing activity against that variant. Therefore, vaccination remains the most effective strategy to combat the COVID-19 pandemic.

microbiology↗

bioRxiv2021

Minor variants of swine H1N1 influenza viruses with enhanced polymerase activity and HA stability promote airborne transmission in ferrets

Understanding how animal influenza A viruses (IAVs) acquire airborne transmissibility in humans and ferrets is needed to prepare for and respond to pandemics. Here, we investigated in ferrets the replication and transmission of swine H1N1 isolates P4 and G15, whose majority population had decreased polymerase activity and poor HA stability, respectively. For both isolates, a minor variant was selected and transmitted in ferrets. Polymerase-enhancing variant PA-S321 airborne-transmitted and propagated in one ferret. HA-stabilizing variant HA1-S210 was selected in all G15-inoculated ferrets and was transmitted by contact and airborne routes. With an efficient polymerase and a stable HA, the purified minor variant G15-HA1-S210 had earlier and higher peak titers in inoculated ferrets and was recovered at a higher frequency after airborne transmission than P4 and G15. Overall, HA stabilization played a more prominent role than polymerase enhancement in the replication and transmission of these viruses in ferrets. The results suggest pandemic risk-assessment studies may benefit from deep sequencing to identify minor variants with human-adapted traits. IMPORTANCEDiverse IAVs circulate in animals, yet few acquire the viral traits needed to start a human pandemic. A stabilized HA and mammalian-adapted polymerase have been shown to promote the adaptation of IAVs to humans and ferrets (the gold-standard model for IAV replication, pathogenicity, and transmissibility). Here, we used swine IAV isolates of the gamma lineage a model to investigate the importance of HA stability and polymerase activity in promoting replication and transmission in ferrets. These are emerging viruses that bind to both -2,6- and -2,3-linked receptors. Using isolates containing mixed populations, a stabilized HA was selected within days in inoculated ferrets. An enhanced polymerase was also selected and propagated after airborne transmission to a ferret. Thus, HA stabilization was a stricter requirement, yet both traits promoted transmissibility. Knowing the viral traits needed for pandemic potential, and the relative importance of each, will help identify emerging viruses of greatest concern.

microbiology↗

bioRxiv2021

Conservation of endangered galaxiid fishes in the Falkland Islands requires urgent action on invasive brown trout

Non-native salmonids are protected in the Southern hemisphere where they sustain aquaculture and valuable sport fisheries, but also impact on native galaxiid fishes, which poses a conservation conundrum. Legal protection and human-assisted secondary releases may have helped salmonids to spread, but this has seldom been tested. We reconstructed the introduction of brown trout (Salmo trutta) to the Falkland Islands using historical records and modelled its dispersal. Our results indicate that establishment success was [~]88%, and that dispersal was facilitated by proximity to introduction sites and density of stream-road crossings, suggesting it was human assisted. Brown trout has already invaded 54% of Falkland rivers, which are 2.9-4.5 times less likely to contain native galaxiids than uninvaded streams. Without strong containment we predict brown trout will invade nearly all suitable freshwater habitats in the Falklands within the next [~]70 years, which might put native freshwater fishes at a high risk of extinction.

ecology↗

bioRxiv2021

Cell-to-cell transmission of HSV1 in human keratinocytes in the absence of the major entry receptor, nectin1

Herpes simplex virus 1 (HSV1) infects the stratified epithelia of the epidermis, oral or genital mucosa, where the main cell type is the keratinocyte. Here we have used nTERT human keratinocytes to generate a CRISPR-Cas9 knockout (KO) of the primary candidate HSV1 receptor, nectin1, resulting in a cell line that is refractory to HSV1 entry. Nonetheless, a small population of KO cells was able to support infection, and strikingly at later times, those cells originally resistant to HSV1 infection had also been infected. Appearance of this later population was blocked by inhibition of virus genome replication, or infection with a{Delta} UL34 virus defective in capsid export to the cytoplasm, while newly formed GFP-tagged capsids were detected in cells surrounding the initial infected cell, suggesting that virus was spreading following replication in the original susceptible cells. Neutralizing human serum failed to block virus transmission in KO cells, which was dependent on the cell-to-cell spread glycoproteins gI and gE, indicating that virus was spreading by direct cell-to-cell transmission. In line with these results, both HSV1 and HSV2 formed plaques on nectin1 KO cells, albeit at a reduced titre, confirming that once the original cell population was infected, the virus could spread into all other cells in the monolayer. Additional siRNA depletion of the second major HSV1 receptor HVEM, or PTP1B, a cellular factor shown elsewhere to be involved in cell-to-cell transmission, had no effect on virus spread in the absence of nectin1. We conclude that although nectin1 is required for extracellular entry in to the majority of human keratinocytes, it is dispensable for direct cell-to-cell transmission. Author SummaryHerpes simplex virus 1 (HSV1) infects the epithelia of the epidermis, oral or genital mucosa to cause cold sores, genital herpes, or more serious outcomes such as keratitis and neonatal herpes. Like many viruses, HSV1 can spread through the extracellular environment or by direct cell-to-cell transmission, with the latter mechanism being important for avoiding antibody responses in the host. Here we have studied HSV1 entry and transmission in the human keratinocyte, the main cell type in the target epithelia, by generating a CRISPR-Cas9 knockout of the primary candidate virus receptor, nectin1. While HSV1 was unable to infect the majority of nectin1 knockout keratinocytes, a small population of these nectin1 KO cells remained susceptible to virus entry, and once infected, the virus was able to spread unhindered into the rest of the monolayer. This spread continued in the presence of neutralising serum which blocks extracellular virus, and required the glycoproteins gE and gI which are known to be involved in cell-to-cell spread. Hence, while nectin1 is required for virus entry into the majority of human keratinocyte cells, it is dispensable for cell-to-cell transmission of the virus. These data have implications for the mechanism of HSV1 epithelial spread and pathogenesis.

microbiology↗

bioRxiv2021

The RAG1 Ubiquitin Ligase Domain Enhances T Cell Receptor Gene Assembly and Thymic Selection

RAG1/RAG2 (RAG) endonuclease-mediated assembly of diverse lymphocyte antigen receptor genes by V(D)J recombination is critical for the development and immune function of T and B cells. However, this process creates highly self-reactive cells that must be properly selected to suppress autoimmunity. The RAG1 protein contains a ubiquitin ligase domain that stabilizes RAG1 and stimulates RAG endonuclease activity in vitro. We report that mice with a mutation that inactivates the RAG1 ubiquitin ligase in vitro exhibit modestly reduced thymic cellularity, decreased assembly and altered repertoires of T cell receptor (TCR) {beta} and genes in thymocytes, and impaired thymocyte developmental transitions that require the assembly of TCR{beta} or genes and signaling by their proteins. These RAG1 mutant mice also exhibit less efficient positive selection and superantigen-mediated negative selection of conventional {beta} T cells, 2) impaired differentiation of iNKT lineage {beta} T cells, and 3) CD4+ {beta} T cells with elevated autoimmune potential. Our findings demonstrate that the RAG1 ubiquitin ligase domain functions in vivo to stimulate the assembly and selection of TCR{beta} and TCR genes, thereby establishing replete diversity of {beta} TCRs and {beta} T cell lineages while restraining the inherent autoimmune hazard of generating diverse antigen specificities.

immunology↗

bioRxiv2020

Screening of Cultivars for Tissue Culture Response and Establishment of Genetic Transformation in a High-yielding and Disease-resistant Cultivar of Theobroma cacao

A highly efficient transformation protocol is a prerequisite to developing genetically modified and genome-edited crops. A tissue culture system spanning the initiation of floral material to the regeneration of plantlets into soil has been tested and improved in cacao. Fourteen cultivars were screened for their tissue culture response and transfer DNA (T-DNA) delivery efficiency via Agrobacterium. These key factors were used to determine the genetic transformability of various cultivars. The high-yielding, disease-resistant cultivar INIAPG-038 was selected for stable transformation and the method was further optimized. Multiple transgenic events were produced using two vectors containing both yellow fluorescent protein and neomycin phosphotransferase II genes. A two-fold strategy to improve both T-DNA delivery and secondary somatic embryogenesis rates was conducted to improve overall transformation frequency. The use of Agrobacterium strain AGL1 and cotyledon tissue derived from immature somatic embryos ranging in size between 4-10 mm resulted in the highest T-DNA delivery efficiency. Furthermore, the use of higher concentrations of basal salts and cupric sulfate in secondary callus growth medium increased the percentage of explants producing greater than ten embryos by 504% and 443%, respectively. Consequently, an optimal combination of all these components resulted in a successful transformation of INIAPG-038 with 3.7% frequency at the T0 plant level. Grafting transgenic scions with undeveloped roots to wild-type seedlings with strong, healthy roots helped make plantlets survive and facilitated quick transplantation to the soil. The present methods can be applied to improve tissue culture response and transformation frequency in other cacao cultivars. Key messageTissue culture and genetic transformation methods for a high-yielding, disease-resistant cultivar of Theobroma cacao were established while factors affecting T-DNA delivery and somatic embryogenesis were identified.

plant biology↗

bioRxiv2020

The Rpi-mcq1 resistance gene family recognizes Avr2 of Phytophthora infestans but is distinct from R2

Potato late blight, which is caused by the destructive oomycete pathogen Phytophthora infestans, is a major threat to global food security. Several nucleotide binding, leucine-rich repeat (NLR) Resistance to P. infestans (Rpi) genes have been introgressed into potato cultivars from wild Solanum species that are native to Mexico, but these were quickly defeated. Positional cloning in Solanum mochiquense, combined with allele mining in Solanum huancabambense, were used to identify a new family of Rpi genes from Peruvian Solanum species. Rpi-mcq1, Rpi-hcb1.1 and Rpi-hcb1.2 confer race-specific resistance to a panel of P. infestans isolates. Effector assays showed that the Rpi-mcq1 family mediates a hypersensitive response upon recognition of the RXLR effector AVR2, which had previously been found to be exclusively recognized by the family of R2 resistance proteins. The Rpi-mcq1 and R2 genes are distinct and reside on chromosome IX and IV, respectively. This is the first report of two unrelated R protein families that recognize the same AVR protein. We anticipate that this likely is a consequence of a geographically separated dynamic co-evolution of R gene families of Solanum with an important effector gene of P. infestans. Author summaryPotato is the largest non-grain staple crop and essential for food security world-wide. However, potato plants are continuously threatened by the notorious oomycete pathogen Phytophthora infestans that causes late blight. This devastating disease has led to the Irish famine more then 150 years ago, and is still a major threat for potato. Resistance against P. infestans can be found in wild relatives of potato, which carry resistance genes that belong to the nucleotide binding site-leucine-rich repeat (NLR) class. Known NLR proteins typically recognize a matching effector from Phytophthora, which leads to a hypersensitive resistance response (HR). For example, R2 from Mexican Solanum species recognizes AVR2 from P. infestans. So far, these R genes exclusively match to one Avr gene. Here, we identified a new class of NLR proteins that are different from R2, but also recognize the same effector AVR2. This new family of NLR occurs in South American Solanum species, and we anticipate that it is likely a product of a geographically separated co-evolution with AVR2. This is the first report of two unrelated R protein families that recognize the same AVR protein.

plant biology↗