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Project acronym ACHILLES-HEEL
Project Crop resistance improvement by mining natural and induced variation in host accessibility factors
Researcher (PI) Sebastian Schornack
Summary Increasing crop yield to feed the world is a grand challenge of the 21st century but it is hampered by diseases caused by filamentous plant pathogens. The arms race between pathogen and plant demands constant adjustment of crop germplasm to tackle emerging pathogen races with new virulence features. To date, most crop disease resistance has relied on specific resistance genes that are effective only against a subset of races. We cannot solely rely on classical resistance genes to keep ahead of the pathogens. There is an urgent need to develop approaches based on knowledge of the pathogen's Achilles heel: core plant processes that are required for pathogen colonization. Our hypothesis is that disease resistance based on manipulation of host accessibility processes has a higher probability for durability, and is best identified using a broad host-range pathogen. I will employ the filamentous pathogen Phytophthora palmivora to mine plant alleles and unravel host processes providing microbial access in roots and leaves of monocot and dicot plants. In Aim 1 I will utilize plant symbiosis mutants and allelic variation to elucidate general mechanisms of colonization by filamentous microbes. Importantly, allelic variation will be studied in economically relevant barley and wheat to allow immediate translation into breeding programs. In Aim 2 I will perform a comparative study of microbial colonization in monocot and dicot roots and leaves. Transcriptional profiling of pathogen and plant will highlight common and contrasting principles and illustrate the impact of differential plant anatomies. We will challenge our findings by testing beneficial fungi to assess commonalities and differences between mutualist and pathogen colonization. We will use genetics, cell biology and genomics to find suitable resistance alleles highly relevant to crop production and global food security. At the completion of the project, I expect to have a set of genes for resistance breeding.
Increasing crop yield to feed the world is a grand challenge of the 21st century but it is hampered by diseases caused by filamentous plant pathogens. The arms race between pathogen and plant demands constant adjustment of crop germplasm to tackle emerging pathogen races with new virulence features. To date, most crop disease resistance has relied on specific resistance genes that are effective only against a subset of races. We cannot solely rely on classical resistance genes to keep ahead of the pathogens. There is an urgent need to develop approaches based on knowledge of the pathogen's Achilles heel: core plant processes that are required for pathogen colonization. Our hypothesis is that disease resistance based on manipulation of host accessibility processes has a higher probability for durability, and is best identified using a broad host-range pathogen. I will employ the filamentous pathogen Phytophthora palmivora to mine plant alleles and unravel host processes providing microbial access in roots and leaves of monocot and dicot plants. In Aim 1 I will utilize plant symbiosis mutants and allelic variation to elucidate general mechanisms of colonization by filamentous microbes. Importantly, allelic variation will be studied in economically relevant barley and wheat to allow immediate translation into breeding programs. In Aim 2 I will perform a comparative study of microbial colonization in monocot and dicot roots and leaves. Transcriptional profiling of pathogen and plant will highlight common and contrasting principles and illustrate the impact of differential plant anatomies. We will challenge our findings by testing beneficial fungi to assess commonalities and differences between mutualist and pathogen colonization. We will use genetics, cell biology and genomics to find suitable resistance alleles highly relevant to crop production and global food security. At the completion of the project, I expect to have a set of genes for resistance breeding.
Project acronym ACTINONSRF
Project MAL: an actin-regulated SRF transcriptional coactivator
Researcher (PI) Richard Treisman
Host Institution (HI) THE FRANCIS CRICK INSTITUTE LIMITED
Summary MAL: an actin-regulated SRF transcriptional coactivator Recent years have seen a revitalised interest in the role of actin in nuclear processes, but the molecular mechanisms involved remain largely unexplored. We will elucidate the molecular basis for the actin-based control of the SRF transcriptional coactivator, MAL. SRF controls transcription through two families of coactivators, the actin-binding MRTFs (MAL, Mkl2), which couple its activity to cytoskeletal dynamics, and the ERK-regulated TCFs (Elk-1, SAP-1, Net). MAL subcellular localisation and transcriptional activity responds to signal-induced changes in G-actin concentration, which are sensed by its actin-binding N-terminal RPEL domain. Members of a second family of RPEL proteins, the Phactrs, also exhibit actin-regulated nucleocytoplasmic shuttling. The proposal addresses the following novel features of actin biology: ¿	Actin as a transcriptional regulator ¿	Actin as a signalling molecule ¿	Actin-binding proteins as targets for regulation by actin, rather than regulators of actin function We will analyse the sequences and proteins involved in actin-regulated nucleocytoplasmic shuttling, using structural biology and biochemistry to analyse its control by changes in actin-RPEL domain interactions. We will characterise the dynamics of shuttling, and develop reporters for changes in actin-MAL interaction for analysis of pathway activation in vivo. We will identify genes controlling MAL itself, and the balance between the nuclear and cytoplasmic actin pools. The mechanism by which actin represses transcriptional activation by MAL in the nucleus, and its relation to MAL phosphorylation, will be elucidated. Finally, we will map MRTF and TCF cofactor recruitment to SRF targets on a genome-wide scale, and identify the steps in transcription controlled by actin-MAL interaction.
MAL: an actin-regulated SRF transcriptional coactivator Recent years have seen a revitalised interest in the role of actin in nuclear processes, but the molecular mechanisms involved remain largely unexplored. We will elucidate the molecular basis for the actin-based control of the SRF transcriptional coactivator, MAL. SRF controls transcription through two families of coactivators, the actin-binding MRTFs (MAL, Mkl2), which couple its activity to cytoskeletal dynamics, and the ERK-regulated TCFs (Elk-1, SAP-1, Net). MAL subcellular localisation and transcriptional activity responds to signal-induced changes in G-actin concentration, which are sensed by its actin-binding N-terminal RPEL domain. Members of a second family of RPEL proteins, the Phactrs, also exhibit actin-regulated nucleocytoplasmic shuttling. The proposal addresses the following novel features of actin biology: ¿	Actin as a transcriptional regulator ¿	Actin as a signalling molecule ¿	Actin-binding proteins as targets for regulation by actin, rather than regulators of actin function We will analyse the sequences and proteins involved in actin-regulated nucleocytoplasmic shuttling, using structural biology and biochemistry to analyse its control by changes in actin-RPEL domain interactions. We will characterise the dynamics of shuttling, and develop reporters for changes in actin-MAL interaction for analysis of pathway activation in vivo. We will identify genes controlling MAL itself, and the balance between the nuclear and cytoplasmic actin pools. The mechanism by which actin represses transcriptional activation by MAL in the nucleus, and its relation to MAL phosphorylation, will be elucidated. Finally, we will map MRTF and TCF cofactor recruitment to SRF targets on a genome-wide scale, and identify the steps in transcription controlled by actin-MAL interaction.
Project acronym ACTSELECTCONTEXT
Project Action Selection under Contextual Uncertainty: the Role of Learning and Effective Connectivity in the Human Brain
Researcher (PI) Sven Bestmann
Summary In a changing world, one hallmark feature of human behaviour is the ability to learn about the statistics of the environment and use this prior information for action selection. Knowing about a forthcoming event allows for adjusting our actions pre-emptively, which can optimize survival. This proposal studies how the human brain learns about the uncertainty in the environment, and how this leads to flexible and efficient action selection. I hypothesise that the accumulation of evidence for future movements through learning reflects a fundamental organisational principle for action control. This explains widely distributed perceptual-, learning-, decision-, and movement-related signals in the human brain. However, little is known about the concerted interplay between brain regions in terms of effective connectivity which is required for flexible behaviour. My proposal seeks to shed light on this unresolved issue. To this end, I will use i) a multi-disciplinary neuroimaging approach, together with model-based analyses and Bayesian model comparison, adapted to human reaching behaviour as occurring in daily life; and ii) two novel approaches for testing effective connectivity: dynamic causal modelling (DCM) and concurrent transcranial magnetic stimulation-functional magnetic resonance imaging. My prediction is that action selection relies on effective connectivity changes, which are a function of the prior information that the brain has to learn about. If true, this will provide novel insight into the human ability to select actions, based on learning about the uncertainty which is inherent in contextual information. This is relevant for understanding action selection during development and ageing, and for pathologies of action such as Parkinson s disease or stroke.
In a changing world, one hallmark feature of human behaviour is the ability to learn about the statistics of the environment and use this prior information for action selection. Knowing about a forthcoming event allows for adjusting our actions pre-emptively, which can optimize survival. This proposal studies how the human brain learns about the uncertainty in the environment, and how this leads to flexible and efficient action selection. I hypothesise that the accumulation of evidence for future movements through learning reflects a fundamental organisational principle for action control. This explains widely distributed perceptual-, learning-, decision-, and movement-related signals in the human brain. However, little is known about the concerted interplay between brain regions in terms of effective connectivity which is required for flexible behaviour. My proposal seeks to shed light on this unresolved issue. To this end, I will use i) a multi-disciplinary neuroimaging approach, together with model-based analyses and Bayesian model comparison, adapted to human reaching behaviour as occurring in daily life; and ii) two novel approaches for testing effective connectivity: dynamic causal modelling (DCM) and concurrent transcranial magnetic stimulation-functional magnetic resonance imaging. My prediction is that action selection relies on effective connectivity changes, which are a function of the prior information that the brain has to learn about. If true, this will provide novel insight into the human ability to select actions, based on learning about the uncertainty which is inherent in contextual information. This is relevant for understanding action selection during development and ageing, and for pathologies of action such as Parkinson s disease or stroke.
Project acronym ADAPT
Project Origins and factors governing adaptation: Insights from experimental evolution and population genomic data
Researcher (PI) Thomas, Martin Jean Bataillon
Host Institution (HI) AARHUS UNIVERSITET
Summary "I propose a systematic study of the type of genetic variation enabling adaptation and factors that limit rates of adaptation in natural populations. New methods will be developed for analysing data from experimental evolution and population genomics. The methods will be applied to state of the art data from both fields. Adaptation is generated by natural selection sieving through heritable variation. Examples of adaptation are available from the fossil record and from extant populations. Genomic studies have supplied many instances of genomic regions exhibiting footprint of natural selection favouring new variants. Despite ample proof that adaptation happens, we know little about beneficial mutations– the raw stuff enabling adaptation. Is adaptation mediated by genetic variation pre-existing in the population, or by variation supplied de novo through mutations? We know even less about what factors limit rates of adaptation. Answers to these questions are crucial for Evolutionary Biology, but also for believable quantifications of the evolutionary potential of populations. Population genetic theory makes predictions and allows inference from the patterns of polymorphism within species and divergence between species. Yet models specifying the fitness effects of mutations are often missing. Fitness landscape models will be mobilized to fill this gap and develop methods for inferring the distribution of fitness effects and factors governing rates of adaptation. Insights into the processes underlying adaptation will thus be gained from experimental evolution and population genomics data. The applicability of insights gained from experimental evolution to comprehend adaptation in nature will be scrutinized. We will unite two very different approaches for studying adaptation. The project will boost our understanding of how selection shapes genomes and open the way for further quantitative tests of theories of adaptation."
"I propose a systematic study of the type of genetic variation enabling adaptation and factors that limit rates of adaptation in natural populations. New methods will be developed for analysing data from experimental evolution and population genomics. The methods will be applied to state of the art data from both fields. Adaptation is generated by natural selection sieving through heritable variation. Examples of adaptation are available from the fossil record and from extant populations. Genomic studies have supplied many instances of genomic regions exhibiting footprint of natural selection favouring new variants. Despite ample proof that adaptation happens, we know little about beneficial mutations– the raw stuff enabling adaptation. Is adaptation mediated by genetic variation pre-existing in the population, or by variation supplied de novo through mutations? We know even less about what factors limit rates of adaptation. Answers to these questions are crucial for Evolutionary Biology, but also for believable quantifications of the evolutionary potential of populations. Population genetic theory makes predictions and allows inference from the patterns of polymorphism within species and divergence between species. Yet models specifying the fitness effects of mutations are often missing. Fitness landscape models will be mobilized to fill this gap and develop methods for inferring the distribution of fitness effects and factors governing rates of adaptation. Insights into the processes underlying adaptation will thus be gained from experimental evolution and population genomics data. The applicability of insights gained from experimental evolution to comprehend adaptation in nature will be scrutinized. We will unite two very different approaches for studying adaptation. The project will boost our understanding of how selection shapes genomes and open the way for further quantitative tests of theories of adaptation."
Project acronym ADaPTIVE
Project Analysing Diversity with a Phenomic approach: Trends in Vertebrate Evolution
Researcher (PI) Anjali Goswami
Host Institution (HI) NATURAL HISTORY MUSEUM
Summary What processes shape vertebrate diversity through deep time? Approaches to this question can focus on many different factors, from life history and ecology to large-scale environmental change and extinction. To date, the majority of studies on the evolution of vertebrate diversity have focused on relatively simple metrics, specifically taxon counts or univariate measures, such as body size. However, multivariate morphological data provides a more complete picture of evolutionary and palaeoecological change. Morphological data can also bridge deep-time palaeobiological analyses with studies of the genetic and developmental factors that shape variation and must also influence large-scale patterns of evolutionary change. Thus, accurately reconstructing the patterns and processes underlying evolution requires an approach that can fully represent an organism's phenome, the sum total of their observable traits. Recent advances in imaging and data analysis allow large-scale study of phenomic evolution. In this project, I propose to quantitatively analyse the deep-time evolutionary diversity of tetrapods (amphibians, reptiles, birds, and mammals). Specifically, I will apply and extend new imaging, morphometric, and analytical tools to construct a multivariate phenomic dataset for living and extinct tetrapods from 3-D scans. I will use these data to rigorously compare extinction selectivity, timing, pace, and shape of adaptive radiations, and ecomorphological response to large-scale climatic shifts across all tetrapod clades. To do so, I will quantify morphological diversity (disparity) and rates of evolution spanning over 300 million years of tetrapod history. I will further analyse the evolution of phenotypic integration by quantifying not just the traits themselves, but changes in the relationships among traits, which reflect the genetic, developmental, and functional interactions that shape variation, the raw material for natural selection.
What processes shape vertebrate diversity through deep time? Approaches to this question can focus on many different factors, from life history and ecology to large-scale environmental change and extinction. To date, the majority of studies on the evolution of vertebrate diversity have focused on relatively simple metrics, specifically taxon counts or univariate measures, such as body size. However, multivariate morphological data provides a more complete picture of evolutionary and palaeoecological change. Morphological data can also bridge deep-time palaeobiological analyses with studies of the genetic and developmental factors that shape variation and must also influence large-scale patterns of evolutionary change. Thus, accurately reconstructing the patterns and processes underlying evolution requires an approach that can fully represent an organism's phenome, the sum total of their observable traits. Recent advances in imaging and data analysis allow large-scale study of phenomic evolution. In this project, I propose to quantitatively analyse the deep-time evolutionary diversity of tetrapods (amphibians, reptiles, birds, and mammals). Specifically, I will apply and extend new imaging, morphometric, and analytical tools to construct a multivariate phenomic dataset for living and extinct tetrapods from 3-D scans. I will use these data to rigorously compare extinction selectivity, timing, pace, and shape of adaptive radiations, and ecomorphological response to large-scale climatic shifts across all tetrapod clades. To do so, I will quantify morphological diversity (disparity) and rates of evolution spanning over 300 million years of tetrapod history. I will further analyse the evolution of phenotypic integration by quantifying not just the traits themselves, but changes in the relationships among traits, which reflect the genetic, developmental, and functional interactions that shape variation, the raw material for natural selection.
Project acronym ALCOHOLLIFECOURSE
Project Alcohol Consumption across the Life-course: Determinants and Consequences
Researcher (PI) Anne Rebecca Britton
Summary The epidemiology of alcohol use and related health consequences plays a vital role by monitoring populations' alcohol consumption patterns and problems associated with drinking. Such studies seek to explain mechanisms linking consumption to harm and ultimately to reduce the health burden. Research needs to consider changes in drinking behaviour over the life-course. The current evidence base lacks the consideration of the complexity of lifetime consumption patterns, the predictors of change and subsequent health risks. Aims of the study 1. To describe age-related trajectories of drinking in different settings and to determine the extent to which individual and social contextual factors, including socioeconomic position, social networks and life events influence drinking pattern trajectories. 2. To estimate the impact of drinking trajectories on physical functioning and disease and to disentangle the exposure-outcome associations in terms of a) timing, i.e. health effect of drinking patterns in early, mid and late life; and b) duration, i.e. whether the impact of drinking accumulates over time. 3. To test the bidirectional associations between health and changes in consumption over the life-course in order to estimate the relative importance of these effects and to determine the dominant temporal direction. 4. To explore mechanisms and pathways through which drinking trajectories affect health and functioning in later life and to examine the role played by potential effect modifiers of the association between drinking and poor health. Several large, longitudinal cohort studies from European countries with repeated measures of alcohol consumption will be combined and analysed to address the aims. A new team will be formed consisting of the PI, a Research Associate and two PhD students. Dissemination will be through journals, conferences, and culminating in a one-day workshop for academics, practitioners and policy makers in the alcohol field.
The epidemiology of alcohol use and related health consequences plays a vital role by monitoring populations' alcohol consumption patterns and problems associated with drinking. Such studies seek to explain mechanisms linking consumption to harm and ultimately to reduce the health burden. Research needs to consider changes in drinking behaviour over the life-course. The current evidence base lacks the consideration of the complexity of lifetime consumption patterns, the predictors of change and subsequent health risks. Aims of the study 1. To describe age-related trajectories of drinking in different settings and to determine the extent to which individual and social contextual factors, including socioeconomic position, social networks and life events influence drinking pattern trajectories. 2. To estimate the impact of drinking trajectories on physical functioning and disease and to disentangle the exposure-outcome associations in terms of a) timing, i.e. health effect of drinking patterns in early, mid and late life; and b) duration, i.e. whether the impact of drinking accumulates over time. 3. To test the bidirectional associations between health and changes in consumption over the life-course in order to estimate the relative importance of these effects and to determine the dominant temporal direction. 4. To explore mechanisms and pathways through which drinking trajectories affect health and functioning in later life and to examine the role played by potential effect modifiers of the association between drinking and poor health. Several large, longitudinal cohort studies from European countries with repeated measures of alcohol consumption will be combined and analysed to address the aims. A new team will be formed consisting of the PI, a Research Associate and two PhD students. Dissemination will be through journals, conferences, and culminating in a one-day workshop for academics, practitioners and policy makers in the alcohol field.
Project acronym ALLQUANTUM
Project All-solid-state quantum electrodynamics in photonic crystals
Researcher (PI) Peter Lodahl
Summary In quantum electrodynamics a range of fundamental processes are driven by omnipresent vacuum fluctuations. Photonic crystals can control vacuum fluctuations and thereby the fundamental interaction between light and matter. We will conduct experiments on quantum dots in photonic crystals and observe novel quantum electrodynamics effects including fractional decay and the modified Lamb shift. Furthermore, photonic crystals will be explored for shielding sensitive quantum-superposition states against decoherence. Defects in photonic crystals allow novel functionalities enabling nanocavities and waveguides. We will use the tight confinement of light in a nanocavity to entangle a quantum dot and a photon, and explore the scalability. Controlled ways of generating scalable and robust quantum entanglement is the essential missing link limiting quantum communication and quantum computing. A single quantum dot coupled to a slowly propagating mode in a photonic crystal waveguide will be used to induce large nonlinearities at the few-photon level. Finally we will explore a novel route to enhanced light-matter interaction employing controlled disorder in photonic crystals. In disordered media multiple scattering of light takes place and can lead to the formation of Anderson-localized modes. We will explore cavity quantum electrodynamics in Anderson-localized random cavities considering disorder a resource and not a nuisance, which is the traditional view. The main focus of the project will be on optical experiments, but fabrication of photonic crystals and detailed theory will be carried out as well. Several of the proposed experiments will constitute milestones in quantum optics and may pave the way for all-solid-state quantum communication with quantum dots in photonic crystals.
In quantum electrodynamics a range of fundamental processes are driven by omnipresent vacuum fluctuations. Photonic crystals can control vacuum fluctuations and thereby the fundamental interaction between light and matter. We will conduct experiments on quantum dots in photonic crystals and observe novel quantum electrodynamics effects including fractional decay and the modified Lamb shift. Furthermore, photonic crystals will be explored for shielding sensitive quantum-superposition states against decoherence. Defects in photonic crystals allow novel functionalities enabling nanocavities and waveguides. We will use the tight confinement of light in a nanocavity to entangle a quantum dot and a photon, and explore the scalability. Controlled ways of generating scalable and robust quantum entanglement is the essential missing link limiting quantum communication and quantum computing. A single quantum dot coupled to a slowly propagating mode in a photonic crystal waveguide will be used to induce large nonlinearities at the few-photon level. Finally we will explore a novel route to enhanced light-matter interaction employing controlled disorder in photonic crystals. In disordered media multiple scattering of light takes place and can lead to the formation of Anderson-localized modes. We will explore cavity quantum electrodynamics in Anderson-localized random cavities considering disorder a resource and not a nuisance, which is the traditional view. The main focus of the project will be on optical experiments, but fabrication of photonic crystals and detailed theory will be carried out as well. Several of the proposed experiments will constitute milestones in quantum optics and may pave the way for all-solid-state quantum communication with quantum dots in photonic crystals.
Project acronym ANXIETY MECHANISMS
Project Neurocognitive mechanisms of human anxiety: identifying and targeting disrupted function
Researcher (PI) Sonia Jane Bishop
Summary Within a 12 month period, 20% of adults will meet criteria for one or more clinical anxiety disorders (ADs). These disorders are hugely disruptive, placing an emotional burden on individuals and their families. While both cognitive behavioural therapy and pharmacological treatment are widely viewed as effective strategies for managing ADs, systematic review of the literature reveals that only 30–45% of patients demonstrate a marked response to treatment (anxiety levels being reduced into the nonaffected range). In addition, a significant proportion of initial responders relapse after treatment is discontinued. There is hence a real and marked need to improve upon current approaches to AD treatment. One possible avenue for improving response rates is through optimizing initial treatment selection. Specifically, it is possible that certain individuals might respond better to cognitive interventions while others might respond better to pharmacological treatment. Recently it has been suggested that there may be two or more distinct biological pathways disrupted in anxiety. If this is the case, then specification of these pathways may be an important step in predicting which individuals are likely to respond to which treatment. Few studies have focused upon this issue and, in particular, upon identifying neural markers that might predict response to cognitive (as opposed to pharmacological) intervention. The proposed research aims to address this. Specifically, it tests the hypothesis that there are at least two mechanisms disrupted in ADs, one entailing amygdala hyper-responsivity to cues that signal threat, the other impoverished recruitment of frontal regions that support cognitive and emotional regulation. Two series of functional magnetic resonance imaging experiments will be conducted. These will investigate differences in amygdala and frontal function during (a) attentional processing and (b) fear conditioning. Initial clinical experiments will investigate whether Generalised Anxiety Disorder and Specific Phobia involve differing degrees of disruption to frontal versus amygdala function during these tasks. This work will feed into training studies, the goal being to characterize AD patient subgroups that benefit from cognitive training.
Within a 12 month period, 20% of adults will meet criteria for one or more clinical anxiety disorders (ADs). These disorders are hugely disruptive, placing an emotional burden on individuals and their families. While both cognitive behavioural therapy and pharmacological treatment are widely viewed as effective strategies for managing ADs, systematic review of the literature reveals that only 30–45% of patients demonstrate a marked response to treatment (anxiety levels being reduced into the nonaffected range). In addition, a significant proportion of initial responders relapse after treatment is discontinued. There is hence a real and marked need to improve upon current approaches to AD treatment. One possible avenue for improving response rates is through optimizing initial treatment selection. Specifically, it is possible that certain individuals might respond better to cognitive interventions while others might respond better to pharmacological treatment. Recently it has been suggested that there may be two or more distinct biological pathways disrupted in anxiety. If this is the case, then specification of these pathways may be an important step in predicting which individuals are likely to respond to which treatment. Few studies have focused upon this issue and, in particular, upon identifying neural markers that might predict response to cognitive (as opposed to pharmacological) intervention. The proposed research aims to address this. Specifically, it tests the hypothesis that there are at least two mechanisms disrupted in ADs, one entailing amygdala hyper-responsivity to cues that signal threat, the other impoverished recruitment of frontal regions that support cognitive and emotional regulation. Two series of functional magnetic resonance imaging experiments will be conducted. These will investigate differences in amygdala and frontal function during (a) attentional processing and (b) fear conditioning. Initial clinical experiments will investigate whether Generalised Anxiety Disorder and Specific Phobia involve differing degrees of disruption to frontal versus amygdala function during these tasks. This work will feed into training studies, the goal being to characterize AD patient subgroups that benefit from cognitive training.
Project acronym APHIDHOST
Project Molecular determinants of aphid host range
Researcher (PI) Jorunn Indra Berit Bos
Host Institution (HI) THE JAMES HUTTON INSTITUTE
Summary Many aphid species are restricted to one or few host plants, while some aphids, many of which are of agricultural importance, can infest a wide range of plant species. An important observation is that aphids spend a considerable time on nonhost species, where they probe the leaf tissue and secrete saliva, but for unknown reasons are unable to ingest phloem sap. This suggest that aphids, like plant pathogens, interact with nonhost plants at the molecular level, but potentially are not successful in suppressing plant defenses and/or releasing nutrients. To date, however, the plant cellular changes and the involvement of immune response, such as ETI and PTI, in aphid-host and -nonhost interactions remain elusive. The aim of the proposed project is to gain insight into the level of cellular host reprogramming that takes place during aphid-host interactions, the cellular processes involved in aphid nonhost resistance, and the role of aphid effectors in determining host range. We will compare interactions of two economically important aphid species, Myzus persicae (green peach aphid) and Rhopalosiphum padi (bird cherry oat aphid), with host and nonhost plants. We will investigate local changes in plant cellular processes during aphid-host and -nonhost interactions using microscopy and biochemistry approaches. We will apply a comparative transcriptomics approach and functional assays to identify aphid effectors as potential determinants of host range. Herein we will specifically looks for aphids-species specific effectors and those that are expressed in specific host interactions. To gain insight into molecular mechanisms of effector activities we will identify host targets and investigate the contribution of effector-target interactions to host range. The expected outcomes of the project will, in the long term, contribute to the development of novel strategies to control infestations by aphids and potentially other pests and pathogens, thereby improving food security.
Many aphid species are restricted to one or few host plants, while some aphids, many of which are of agricultural importance, can infest a wide range of plant species. An important observation is that aphids spend a considerable time on nonhost species, where they probe the leaf tissue and secrete saliva, but for unknown reasons are unable to ingest phloem sap. This suggest that aphids, like plant pathogens, interact with nonhost plants at the molecular level, but potentially are not successful in suppressing plant defenses and/or releasing nutrients. To date, however, the plant cellular changes and the involvement of immune response, such as ETI and PTI, in aphid-host and -nonhost interactions remain elusive. The aim of the proposed project is to gain insight into the level of cellular host reprogramming that takes place during aphid-host interactions, the cellular processes involved in aphid nonhost resistance, and the role of aphid effectors in determining host range. We will compare interactions of two economically important aphid species, Myzus persicae (green peach aphid) and Rhopalosiphum padi (bird cherry oat aphid), with host and nonhost plants. We will investigate local changes in plant cellular processes during aphid-host and -nonhost interactions using microscopy and biochemistry approaches. We will apply a comparative transcriptomics approach and functional assays to identify aphid effectors as potential determinants of host range. Herein we will specifically looks for aphids-species specific effectors and those that are expressed in specific host interactions. To gain insight into molecular mechanisms of effector activities we will identify host targets and investigate the contribution of effector-target interactions to host range. The expected outcomes of the project will, in the long term, contribute to the development of novel strategies to control infestations by aphids and potentially other pests and pathogens, thereby improving food security.
Project acronym ArtifiCell
Project Synthetic Cell Biology: Designing organelle transport mechanisms
Researcher (PI) James Edward Rothman
Summary Imagine being able to design into living cells and organisms de novo vesicle transport mechanisms that do not naturally exist? At one level this is a wild-eyed notion of synthetic biology. But we contend that this vision can be approached even today, focusing first on the process of exocytosis, a fundamental process that impacts almost every area of physiology. Enough has now been learned about the natural core machinery (as recognized by the award of the 2013 Nobel Prize in Physiology or Medicine to the PI and others) to take highly innovative physics/engineering- and DNA-based approaches to design synthetic versions of the secretory apparatus that could someday open new avenues in genetic medicine. The central idea is to introduce DNA-based functional equivalents of the core protein machinery that naturally form (coats), target (tethers), and fuse (SNAREs) vesicles. We have already taken first steps by using DNA origami-based templates to produce synthetic phospholipid vesicles and complementary DNA-based tethers to specifically capture these DNA-templated vesicles on targeted bilayers. Others have linked DNA oligonucleotides to trigger vesicle fusion. The next and much more challenging step is to introduce such processes into living cells. We hope to break this barrier, and in the process start a new field of research into "synthetic exocytosis", by introducing Peptide-Nucleic Acids (PNAs) of tethers and SNAREs to re-direct naturally-produced secretory vesicles to artificially-programmed targets and provide artificially-programmed regulation. PNAs are chosen mainly because they lack the negatively charged phosphate backbones of DNA, and therefore are more readily delivered into the cell across the plasma membrane. Future steps, would include producing the transport vesicles synthetically within the cell by externally supplied origami-based PNA or similar cages, and - much more speculatively - ultimately using encoded DNA and RNAs to provide these functions.
Imagine being able to design into living cells and organisms de novo vesicle transport mechanisms that do not naturally exist? At one level this is a wild-eyed notion of synthetic biology. But we contend that this vision can be approached even today, focusing first on the process of exocytosis, a fundamental process that impacts almost every area of physiology. Enough has now been learned about the natural core machinery (as recognized by the award of the 2013 Nobel Prize in Physiology or Medicine to the PI and others) to take highly innovative physics/engineering- and DNA-based approaches to design synthetic versions of the secretory apparatus that could someday open new avenues in genetic medicine. The central idea is to introduce DNA-based functional equivalents of the core protein machinery that naturally form (coats), target (tethers), and fuse (SNAREs) vesicles. We have already taken first steps by using DNA origami-based templates to produce synthetic phospholipid vesicles and complementary DNA-based tethers to specifically capture these DNA-templated vesicles on targeted bilayers. Others have linked DNA oligonucleotides to trigger vesicle fusion. The next and much more challenging step is to introduce such processes into living cells. We hope to break this barrier, and in the process start a new field of research into "synthetic exocytosis", by introducing Peptide-Nucleic Acids (PNAs) of tethers and SNAREs to re-direct naturally-produced secretory vesicles to artificially-programmed targets and provide artificially-programmed regulation. PNAs are chosen mainly because they lack the negatively charged phosphate backbones of DNA, and therefore are more readily delivered into the cell across the plasma membrane. Future steps, would include producing the transport vesicles synthetically within the cell by externally supplied origami-based PNA or similar cages, and - much more speculatively - ultimately using encoded DNA and RNAs to provide these functions.