Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Operational research

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Eliminating Summer Fallow Reduces Winter Wheat Yields, but Not Necessarily System Profitability

Summer fallow is commonly used to stabilize winter wheat (Triticum aestivum L.) production in the Central Great Plains, but summer fallow results in soil degradation, limits farm productivity and profitability, and stores soil water inefficiently. The objectives of this study were to quantify the production and economic consequences of replacing summer fallow with spring-planted crops on the subsequent winter wheat crop. A summer fallow treatment and five spring crop treatments [spring canola (Brassica napus L.), oat (Avena sativa L.) + pea (Pisum sativum L.) for forage, proso millet (Panicum miliaceum L.), dry bean (Phaseolus vulgaris L.), and corn (Zea mays L.)] were no-till seeded into sunflower (Helianthus annuus L.) residue in a randomized complete block design with five replications during 1999, 2000, and 2001. Winter wheat was planted in the fall following the spring crops. Five N fertilizer treatments (0, 22, 45, 67, and 90 kg N ha-1) were randomly assigned to each previous spring crop treatment in a split-plot treatment arrangement. The 3-yr mean wheat grain yield after summer fallow was 29% greater than following oat + pea for forage and 86% greater than following corn. The 3-yr mean annualized net return for the spring crop and subsequent winter wheat crop was $4.20, -$6.91, -$7.55, -$29.66, -$81.17, and -$94.88 ha-1 for oat + pea for forage, proso millet, summer fallow, dry bean, corn, and spring canola, respectively. Systems involving oat + pea for forage and proso millet are economically competitive with systems using summer fallow

G89-899 Weed Control in No-Till Corn, Grain Sorghum and Soybean Production

Tips for successful no-till weed control, weed control principles for no-till row crop production, and no-till row crops planted into legume or small grain residues are covered here. Soil erosion by wind and water is a strong societal concern in our state and nation. Current estimates are that more than 100 million tons of topsoil are eroded annually in Nebraska, with 75 percent of that coming from row crop areas. Nebraska farmers have been implementing changes in their crop production practices to reduce soil erosion

G92-1081 Factors That Affect Soil-Applied Herbicides

Characteristics of soil-applied herbicides are discussed, including site of uptake by weeds, solubility, adsorption, persistence, leaching potential, photodecomposition, and volatility. For best performance, preemergence and preplant herbicides must be placed in the top 0 to 3 inches of soil. Placement is important because the herbicide must enter the germinating weed seedling in order to kill it. Herbicides can be blended into the soil by mechanical incorporation, rainfall, or sprinkler irrigation, depending on the herbicide. Herbicide characteristics that determine their performance are site of uptake by weeds, solubility, adsorption, persistence, leaching potential, photodecomposition, and volatility. An understanding of these factors will result in more effective herbicide use