Evaluating Large Spontaneous Deletions in a Bovine Cell Line Selected for Bovine Viral Diarrhea Virus Resistance

Bovine viral diarrhea virus’s (BVDV) entry into bovine cells involves attachment of virions to cellular receptors, internalization, and pH-dependent fusion with endosomal membranes. The primary host receptor for BVDV is CD46; however, the complete set of host factors required for virus entry is unknown. The Madin-Darby bovine kidney (MDBK) cell line is susceptible to BVDV infection, while a derivative cell line (CRIB) is resistant at the level of virus entry. We performed complete genome sequencing of each to identify genomic variation underlying the resistant phenotype with the aim of identifying host factors essential for BVDV entry. Three large compound deletions in the BVDV-resistant CRIB cell line were identified and predicted to disrupt the function or expression of the genes PTPN12, GRID2, and RABGAP1L. However, CRISPR/Cas9 mediated knockout of these genes, individually or in combination, in the parental MDBK cell line did not impact virus entry or replication. Therefore, resistance to BVDV in the CRIB cell line is not due to the apparent spontaneous loss of PTPN12, GRID2, or RABGAP1L gene function. Identifying the functional cause of BVDV resistance in the CRIB cell line may require more detailed comparisons of the genomes and epigenomes

First gene-edited calf with reduced susceptibility to a major viral pathogen

Bovine viral diarrhea virus (BVDV) is one of the most important viruses affecting the health and well-being of bovine species throughout the world. Here, we used CRISPR-mediated homology-directed repair and somatic cell nuclear transfer to produce a live calf with a six amino acid substitution in the BVDV binding domain of bovine CD46. The result was a gene-edited calf with dramatically reduced susceptibility to infection as measured by reduced clinical signs and the lack of viral infection in white blood cells. The edited calf has no off-target edits and appears normal and healthy at 20 months of age without obvious adverse effects from the on-target edit. This precision bred, proof-of-concept animal provides the first evidence that intentional genome alterations in the CD46 gene may reduce the burden of BVDV-associated diseases in cattle and is consistent with our stepwise, in vitro and ex vivo experiments with cell lines and matched fetal clones

Environmental Influences on Growth and Reproduction of Invasive Commelina benghalensis

Commelina benghalensis (Benghal dayflower) is a noxious weed that is invading agricultural systems in the southeastern United States. We investigated the influences of nutrition, light, and photoperiod on growth and reproductive output of C. benghalensis. In the first experimental series, plants were grown under high or low soil nutrition combined with either full light or simulated shade. Lowered nutrition strongly inhibited vegetative growth and aboveground spathe production. Similar but smaller effects were exerted by a 50% reduction in light, simulating conditions within a developing canopy. In the second series of experiments, C. benghalensis plants were exposed to different photoperiod conditions that produced short- and long-day plants growing in similar photosynthetic periods. A short-day photoperiod decreased time to flowering by several days and led to a 40 to 60% reduction in vegetative growth, but reproduction above and below ground was unchanged. Collectively, the results indicate that (1) fertility management in highly weathered soils may strongly constrain competitiveness of C. benghalensis; (2) shorter photoperiods will limit vegetative competitiveness later in the growing seasons of most crops; and (3) the high degree of reproductive plasticity and output possessed by C. benghalensis will likely cause continual persistence problems in agricultural fields

Influenza A Virus (H3N8) in Dogs with Respiratory Disease, Florida

Genetic and antigenic characterization established the uniqueness of this virus circulating in dogs

Influenza A Virus (H3N8) in Dogs with Respiratory Disease, Florida

Genetic and antigenic characterization established the uniqueness of this virus circulating in dogs

Acetyl-CoA Carboxylase Herbicide Tolerance in Bermudagrass

Contamination of newly planted bermudagrass (Cynodon spp.) varieties by undesirable off-type bermudagrass genotypes is an ever increasing concern for turf managers because selective control options are limited. In 2009, a sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} tolerant bermudagrass genotype (93-175) was identified during herbicide screening at the University of Georgia in Tifton. The objective of this research was to assess the tolerance of 93-175 to three Acetyl-CoA carboxylase (ACCase) herbicides in comparison to the susceptible genotypes Tifway and common bermudagrass. Greenhouse and field trials were performed between August 2011 and April 2013. Factors in the field experiment included ACCase herbicides, application rates, bermudagrass genotypes, and locations. Turfgrass injury ratings taken 42 days after treatment (DAT) and during greenup the following spring supported initial preliminary findings. At the 1x rate of sethoxydim (280 g a.i. ha⁻¹), 93-175 displayed 50 to 87% less injury in comparison to the susceptible genotypes. In the spring of 2013, 93-175 plots treated with a 1x rate of sethoxydim reached 100% recovery during the same time period as non-treated controls, while common and Tifway had only recovered to 48 and 60%, respectively. The tolerance mechanism of 93-175 to sethoxydim did not confer an appreciable reduction of clethodim {(E,E)-(6)-2-[1-[[(3-chloro-2-propenyl)oxy]imino]propyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen- 1-one} or fluazifop {(6)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid} herbicide treatment effects. 93-175 will continue to be studied to determine transferability of herbicide tolerance to progeny and the mechanism of the observed tolerance

Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops

Development of herbicide-resistant crops has resulted in significant changes to agronomic practices, one of which is the adoption of effective, simple, low-risk, crop-production systems with less dependency on tillage and lower energy requirements. Overall, the changes have had a positive environmental effect by reducing soil erosion, the fuel use for tillage, and the number of herbicides with groundwater advisories as well as a slight reduction in the overall environmental impact quotient of herbicide use. However, herbicides exert a high selection pressure on weed populations, and density and diversity of weed communities change over time in response to herbicides and other control practices imposed on them. Repeated and intensive use of herbicides with the same mechanisms of action (MOA; the mechanism in the plant that the herbicide detrimentally affects so that the plant succumbs to the herbicide; e.g., inhibition of an enzyme that is vital to plant growth or the inability of a plant to metabolize the herbicide before it has done damage) can rapidly select for shifts to tolerant, difficult-to-control weeds and the evolution of herbicide-resistant weeds, especially in the absence of the concurrent use of herbicides with different mechanisms of action or the use of mechanical or cultural practices or both.This is the publisher’s final pdf. The published article is copyrighted by the Weed Science Society of America and can be found at: http://wssajournals.org/loi/wee

Interactions between rootstock, inter-stem and scion xylem vessel characteristics of peach trees growing on rootstocks with contrasting size-controlling characteristics

This paper documents that while characteristics of the xylem anatomy and calculated hydraulic conductance of peach rootstock genotypes differ according to their effects on vigour of the scion they do not strongly influence the xylem characteristics of the scion. Furthermore xylem characteristics of a dwarfing rootstock genotype used as an inter-stem do not substantially influence anatomical characteristics of a vigorous rootstock below the inter-stem or the scion above it