Inhibition of ethylene involved in resistance to E. turcicum in an exotic-derived double haploid maize population

Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots

Embodied viewing and Degas’s Little Dancer Aged Fourteen: a multi-disciplinary experiment in eye-tracking and motion capture

This paper presents a cross-disciplinary project based on an experiment in eye-tracking and motion capture (Sainsbury’s Centre for Visual Arts), which aimed to study viewers’ movements around an iconic sculpture: Edgar Degas’s Little Dancer Aged Fourteen. The experiment studies how viewers respond to this three-dimensional artwork not only by looking at it but also through their own bodily reactions to it, such as by unconsciously mimicking a represented attitude or gesture. We compared two groups of viewers: classically trained dancers and non-dancers. Our hypothesis was that the skills and embodied experiences of the dancers would alter the ways in which they engage bodily with the work compared to the non-dancers. Our underlying research question was: how are vision and the body interlinked in esthetic and kinesthetic experience? This paper does not give results, which are forthcoming. It focuses on methodology and provides a commentary on the design and development of the interdisciplinary collaboration behind the project. It explores an interdisciplinary collaboration that bridges the humanities and experimental sciences and asks how being confronted with unfamiliar methodologies forces researchers in a given field to critically self-examine the limits and presuppositions of their practices

Identifying loci conferring quantitative disease resistance in sorghum and maize against fungal foliar pathogens

There are multiple mechanisms by which hosts defend themselves against pathogens. Broadly disease resistance can be split into qualitative and quantitative resistance. In qualitative resistance the presence of a single resistance gene (R gene) confers complete resistance against the pathogen. R proteins can interact directly as receptors or indirectly as guardees/decoys with pathogen Avr proteins. R genes are generally race specific. Quantitative disease resistance (QDR) is genetically complex with a partial phenotype conferred by multiple small effect genes. In some instances genes and loci associated with QDR confer broad spectrum resistance against multiple of pathogens (Singh et al., 2011a). Many QDR genes are not directly associated with host defense responses but with host morphology and development, signal transduction, and the general defense response, among other mechanisms. The mechanisms underlying qualitative resistance are well understood through many detailed analyses (Spoel and Dong, 2012; Song et al., 2015; Balint-Kurti, 2019; Dievart et al., 2020; Sun et al., 2020). By contrast the mechanisms associated with QDR remains largely elusive. The deployment of resistant germplasm is an economically efficient means to manage disease. However, high selection pressure on pathogens with high evolutionary potential can lead to pathogens overcoming host resistance. Durability of resistance can be maintained through genetic complexity. Genetic complexity is established by stacking both R genes and QDR genes through pyramiding (Mundt, 2018). As complexity increases, pathogens are required to evade multiple forms of detection. Maize is a model organism and has been studied for resistance to a variety of diseases. Northern corn leaf blight and sorghum leaf blight are both caused by the hemibiotrophic fungus Exserohilum turcicum. Both qualitative and quantitative resistance against E. turcicum have been described in maize. In contrast, the genetic architecture of resistance against E. turcicum in sorghum is poorly understood. Maize and sorghum are closely related C4 grass species, and likely share mechanisms of resistance to E. turcicum. Identification of resistance in sorghum against E. turcicum can enhance management strategies and understanding of the pathosystem. By definition, emerging diseases are not as well understood. Phyllachora maydis, the causal agent of tar spot in maize was identified in the United States in 2015. The role of environmental conditions is important in the P. maydis pathosystem. Resistance has been identified in tropical germplasm but not in temperate-adapted germplasm. Accessions developed by the Germplasm Enhancement of Maize (GEM) project contain introgressions from landraces in elite backgrounds. Screening exotic-derived germplasm will aid in the identification of donors for alleles contributing towards resistance to tar spot. Chapter 1 is a literature review of disease resistance in crops, specifically on quantitative and qualitative disease resistance in maize. Chapter 2 is a QTL mapping study that identifies loci for resistance to E. turcicum in two sorghum recombinant inbred line populations. The distribution of resistance loci in sorghum is non-random. The relationship of resistance to E. turcicum between maize and sorghum is examined, and maize genes for resistance colocalize within the sorghum leaf blight resistance loci. Sorghum and maize likely utilize similar mechanisms of resistance against E. turcicum. The main objective of Chapter 3 is to identify sources of resistance to tar spot in exotic-derived germplasm. Environmental conditions have a strong influence on disease severity, but consistent phenotypic responses are observed across environments. Disease symptoms vary between juvenile and adult plants. Accessions with potential for use in breeding for tar spot resistance are described. Chapter 4 summarizes the findings from Chapters 2 and 3 and discusses implications for future research goals of confirming a QTL on chromosome 3 in sorghum associated with resistance against E. turcicum. Chapter 4 also discusses implications of environmental modeling for predicating disease development and further identifying sources of resistance to tar spot in maize.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

DataSheet_1_Inhibition of ethylene involved in resistance to E. turcicum in an exotic-derived double haploid maize population.csv

Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots.</p

DataSheet_3_Inhibition of ethylene involved in resistance to E. turcicum in an exotic-derived double haploid maize population.csv

Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots.</p

Image_1_Inhibition of ethylene involved in resistance to E. turcicum in an exotic-derived double haploid maize population.pdf

Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots.</p

DataSheet_2_Inhibition of ethylene involved in resistance to E. turcicum in an exotic-derived double haploid maize population.csv

Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots.</p

HIV Distal Neuropathic Pain Is Associated with Smaller Ventral Posterior Cingulate Cortex

Objective. Despite modern antiretroviral therapy, HIV-associated neuropathy is one of the most prevalent, disabling and treatment-resistant complications of HIV disease. The presence and intensity of distal neuropathic pain is not fully explained by the degree of peripheral nerve damage. A better understanding of brain structure in HIV distal neuropathic pain may help explain why some patients with HIV neuropathy report pain while the majority does not. Previously, we reported that more intense distal neuropathic pain was associated with smaller total cerebral cortical gray matter volumes. The objective of this study was to determine which parts of the cortex are smaller.Methods. HIV positive individuals with and without distal neuropathic pain enrolled in the multisite (N = 233) CNS HIV Antiretroviral Treatment Effects (CHARTER) study underwent structural brain magnetic resonance imaging. Voxel-based morphometry was used to investigate regional brain volumes in these structural brain images.Results. Left ventral posterior cingulate cortex was smaller for HIV positive individuals with versus without distal neuropathic pain (peak P  = 0.017; peak t = 5.15; MNI coordinates x = -6, y = -54, z = 20). Regional brain volumes within cortical gray matter structures typically associated with pain processing were also smaller for HIV positive individuals having higher intensity ratings of distal neuropathic pain.Conclusions. The posterior cingulate is thought to be involved in inhibiting the perception of painful stimuli. Mechanistically a smaller posterior cingulate cortex structure may be related to reduced anti-nociception contributing to increased distal neuropathic pain