Search Results for: EPSPS

Abstract: Transgenic glyphosate-tolerant plants overproducing EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) may exhibit enhanced fitness in glyphosate-free environments. If so, introgression of transgenes overexpressing EPSPS into wild relative species may lead to increased competitiveness of crop-wild hybrids, resulting in unpredicted environmental impact. Assessing fitness effects of transgenes overexpressing EPSPS in a model plant species can help address this …

Abstract: Amplification of the EPSPS gene has been previously identified as the glyphosate resistance mechanism in many populations of Amaranthus palmeri, a major weed pest in US agriculture. Here, we evaluate the effects of EPSPS gene amplification on both the level of glyphosate resistance and fitness cost of resistance. A. palmeri individuals resistant to glyphosate …

Abstract: BACKGROUND: Amaranthus spinosus, a common weed of pastures, is a close relative of Amaranthus palmeri, a problematic agricultural weed with widespread glyphosate resistance. These two species have been known to hybridize, allowing for transfer of glyphosate resistance. Glyphosate-resistant A. spinosus was recently suspected in a cotton field in Mississippi. RESULTS: Glyphosate-resistant A. spinosus biotypes …

Abstract: BACKGROUND Glyphosate is the most widely used herbicide in the world and has been intensively used to control B. diandrus, a problematic weed of crops and pastures in southern Australia. RESULTS Resistance to glyphosate was identified in two populations of B. diandrus that were nearly fivefold more resistant to glyphosate than wild‐type plants. Both …

Abstract: In Argentina, glyphosate resistance was reported in a Lolium perenne population after 12 years of successful herbicide use. The aim of the current paper was to put in evidence for the mechanism of glyphosate resistance of this weed. Susceptible leaves treated with different doses of glyphosate and incubated in vitro showed an accumulation of …

Abstract: The herbicide glyphosate became widely used in the United States and other parts of the world after the commercialization of glyphosate-resistant crops. These crops have constitutive overexpression of a glyphosate-insensitive form of the herbicide target site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Increased use of glyphosate over multiple years imposes selective genetic pressure on weed populations. …

Abstract: Sampling methods and results of a gene flow study are described that will be of interest to plant scientists, evolutionary biologists, ecologists, and stakeholders assessing the environmental safety of transgenic crops. This study documents gene flow on a landscape level from creeping bentgrass (Agrostis stolonifera L.), one of the first wind-pollinated, perennial, and highly …

Abstract: The use of transgenic crops as feeds for ruminant animals has prompted study of the possible uptake of transgene fragments by ruminal micro-organisms and/or intestinal absorption of fragments surviving passage through the rumen. The persistence in buffered ruminal contents of seven different recombinant DNA fragments from GM rapeseed expressing the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) transgene …

Abstract: Glyphosate-resistant (GR) kochia is an increasing management concern in major cropping systems of the northwestern US. In 2014, we investigated four putative GR kochia accessions (designated as ALA, VAL, WIL, DB) collected from sugar beet fields in eastern Oregon and southwestern Idaho to characterize the level of evolved glyphosate resistance and determine the relationship …

Abstract: The persistence and movement of transgenic DNA in agricultural and natural systems is largely unknown. This movement poses a threat of horizontal gene transfer and possible proliferation of genetically modified DNA into the general environment. To assess the persistence of transgenic DNA in a field of Roundup Ready corn, we quantified the presence of …

Abstract: The persistence and movement of transgenic DNA in agricultural and natural systems is largely unknown. This movement poses a threat of horizontal gene transfer and possible proliferation of genetically modified DNA into the general environment. To assess the persistence of transgenic DNA in a field of Roundup Ready® corn, we quantified the presence of …

Abstract: Concerns about genetically modified (GM) crops include transgene flow to compatible wild species and unintended ecological consequences of potential transgene introgression. However, there has been little empirical documentation of establishment and distribution of transgenic plants in wild populations. We present herein the first evidence for escape of transgenes into wild plant populations within the …

Abstract: Understanding evolutionary interactions among crops and weeds can facilitate effective weed management. For example, gene flow from crops to their wild or weedy relatives can lead to rapid evolution in recipient populations. In rice (Oryza sativa), transgenic herbicide resistance is expected to spread to conspecific weedy rice (Oryza sativa f. spontanea) via hybridization. Here, …

Abstract: The glyphosate herbicide has been extensively used for long time periods in woody crops to control a broad range of weeds. The rapid determination of resistant weeds in different woody crops could maintain the efficacy of herbicides and could improve weed management using rotating strategies. Unfortunately Sumatran fleabane has developed a resistance to glyphosate. …

Abstract: The mechanism of glyphosate resistance in horseweed was investigated. Eleven biotypes of putative sensitive (S) and resistant (R) horseweed were obtained from regions across the United States and examined for foliar retention, absorption, translocation, and metabolism of glyphosate. Initial studies used spray application of 14C-glyphosate to simulate field application. When S and R biotypes …

Abstract: The continuous use of glyphosate has resulted in the selection of resistant biotypes in 13 different weed species. Three different mechanisms of resistance have been proposed for these biotypes: 1) Decreased translocation to meristems; 2) Mutation of target site 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS) and 3) Increased expression of EPSPS. Decreased translocation of glyphosate to the …

Text: Gressel et al. (2014; in this issue of New Phytologist, pp. 360–362) disapprove of media coverage of our recent peer‐reviewed paper (Wang et al., 2014; this issue of New Phytologist, pp. 679–683), and they question whether the paper can be seen as ‘deserving publication’. In this study, our main hypothesis was that over‐production of …

Text: Grunewald & Bury (2014; in this issue of New Phytologist, pp. 367–369) criticize our recent peer‐reviewed paper (Wang et al., 2014; in this issue of New Phytologist, pp. 679–683), stating that we ‘unnecessarily harm the sensitive debate on GM crops.’ We will not focus on this politically charged topic here, but we do want …

Abstract: We constructed a mixed‐species community designed to simulate roadside and field edge plant communities and exposed it to glyphosate drift in order to test three hypotheses: (1) higher fitness in transgenic Brassica carrying the CP4 EPSPS transgene that confers resistance to glyphosate will result in significant changes in the plant community relative to control …

Abstract: Evolution of multiple herbicide resistance in weeds is a serious threat to weed management in crop production. Kochia is an economically important broadleaf weed in the US Great Plains. This study aimed to confirm resistance to four sites of action of herbicides in a single kochia (Kochia scoparia L. Schrad.) population from a crop …