First report of target-site resistance to ACCase-inhibiting herbicides in Bromus tectorum L.

Background: The prevalent and repeated use of acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides for Bromus tectorum L. control in fine fescue (Festuca L. spp) grown for seed has selected ACCase-resistant B.

Constitutive overexpression of EPSPS by gene duplication is involved in glyphosate resistance in Salsola tragus.

Background: Glyphosate-resistant Salsola tragus accessions have been identified in the USA and Argentina; however, the mechanisms of glyphosate resistance have not been elucidated. The goal of this study was to determine the mechanism/s of glyphosate resistance involved in two S. tragus populations (R1 and R2) from Argentina.

Toward product-based regulation of crops.

Current process-based approaches to regulation are no longer fit for purpose.

Black Leg and Chlorotic Leaf Spot Occurrence on Brassicaceae Crop and Weed Hosts.

Black leg (caused by and ) and chlorotic leaf spot (caused by ) are economically important fungal diseases of Brassicaceae crops. Surveys of seed fields and weed hosts were conducted to understand the distribution and prevalence of these diseases in Oregon after black leg and chlorotic leaf spot outbreaks occurred in Brassicaceae crops in 2014. Postharvest black leg ratings were conducted in seed fields of canola, forage rape, and turnip in 2015 and 2016.

Non-target-Site Resistance in spp. Globally: A Review.

The genus encompasses many species that colonize a variety of disturbed and non-disturbed environments. L. spp.

Genome Editing, Gene Drives, and Synthetic Biology: Will They Contribute to Disease-Resistant Crops, and Who Will Benefit?

Genetically engineered crops have been grown for more than 20 years, resulting in widespread albeit variable benefits for farmers and consumers. We review current, likely, and potential genetic engineering (GE) applications for the development of disease-resistant crop cultivars. Gene editing, gene drives, and synthetic biology offer novel opportunities to control viral, bacterial, and fungal pathogens, parasitic weeds, and insect vectors of plant pathogens.

Role of Glutamine Synthetase Isogenes and Herbicide Metabolism in the Mechanism of Resistance to Glufosinate in L. spp. Biotypes from Oregon.

Glufosinate-resistant L. spp. biotypes from Oregon exhibited resistance levels up to 2.

Gene flow from single and stacked herbicide-resistant rice (Oryza sativa): modeling occurrence of multiple herbicide-resistant weedy rice.

Background: Provisia™ rice (PV), a non-genetically engineered (GE) quizalofop-resistant rice, will provide growers with an additional option for weed management to use in conjunction with Clearfield rice (CL) production. Modeling compared the impact of stacking resistance traits versus single traits in rice on introgression of the resistance trait to weedy rice (also called red rice). Common weed management practices were applied to 2-, 3- and 4-year crop rotations, and resistant and multiple-resistant weedy rice seeds, seedlings and mature plants were tracked for 15 years.

Comparison of growth and physiological characteristics between roughstalk bluegrass and tall fescue in response to simulated waterlogging.

Roughstalk bluegrass (Poa trivialis) is a weed in cool season grass seed production fields in Oregon. Populations of this weed are often greater in fields prone to waterlogging. A greenhouse study was conducted to investigate the morphological and physiological differences between recently established roughstalk bluegrass and tall fescue (Lolium arundinaceum) plants in response to simulated waterlogging.

Pollen-mediated gene flow from transgenic perennial creeping bentgrass and hybridization at the landscape level.

The planting of 162 ha of transgenic glyphosate-resistant creeping bentgrass (Agrostis stolonifera) near Madras, OR, USA, allowed a unique opportunity to study gene flow over time from a perennial outcrossing species at the landscape level. While conducting a four year in situ survey, we collected panicles and leaf tissue samples from creeping bentgrass and its sexually compatible species. Seeds from the panicles were planted, and seedlings were tested in the greenhouse for expression of the transgene.

Identification of glyphosate resistance in Salsola tragus in north-eastern Oregon.

Background: Farmers in the low-rainfall region of eastern Oregon rely on repeated applications of non-selective herbicides, predominately glyphosate, to control Salsola tragus in no-till fallow systems. Reports of poor glyphosate effectiveness have increased in recent years. Reduced efficacy is often attributed to dust, water stress, or generally poor growing conditions during application.

Impact of transgene genome location on gene migration from herbicide-resistant wheat (Triticum aestivum L.) to jointed goatgrass (Aegilops cylindrica Host).

Background: Wheat (Triticum aestivum) (ABD) and jointed goatgrass (Aegilops cylindrica) (CD) can cross and produce hybrids that can backcross to either parent. Such backcrosses can result in progeny with chromosomes and/or chromosome segments retained from wheat. Thus, a herbicide resistance gene could migrate from wheat to jointed goatgrass.

Identification and phytotoxicity of a new glucosinolate breakdown product from Meadowfoam (Limnanthes alba) seed meal.

Meadowfoam (Limnanthes alba Hartw. ex Benth.) is an oilseed crop grown in the Willamette Valley of Oregon.

Characterization of multiple-herbicide-resistant Italian ryegrass (Lolium perenne spp. multiflorum).

Background: Multiple-herbicide resistance in Lolium perenne spp. multiflorum has evolved in many areas in Oregon. To manage the resistant populations, the resistance patterns must be determined.

Development of a chloroplast DNA marker for monitoring of transgene introgression in Brassica napus L.

Chloroplast molecular markers can provide useful information for high-resolution analysis of inter- and intra-specific variation in Brassicaceae and for differentiation between its species. Combining data generated from nuclear and chloroplast markers enables the study of seed and pollen movement, and assists in the assessment of gene-flow from genetically modified (GM) plants through hybridization studies. To develop chloroplast DNA markers for monitoring of transgene introgression in Brassica napus L.

Crossing the divide: gene flow produces intergeneric hybrid in feral transgenic creeping bentgrass population.

Gene flow is the most frequently expressed public concern related to the deregulation of transgenic events (Snow 2002; Ellstrand 2003). However, assessing the potential for transgene escape is complex because it depends on the opportunities for unintended gene flow, and establishment and persistence of the transgene in the environment (Warwick et al. 2008).

Target-site mutation associated with glufosinate resistance in Italian ryegrass (Lolium perenne L. ssp. multiflorum).

Background: Studies were conducted to elucidate the mechanism of glufosinate resistance in an Italian ryegrass population.

Results: Glufosinate rates required to reduce growth by 50% (GR(50)) were 0.15 and 0.

Development of novel chloroplast microsatellite markers to identify species in the Agrostis complex (Poaceae) and related genera.

We needed a reliable way to identify species and confirm potential interspecific and intergeneric hybrids in a landscape level study of gene flow from transgenic glyphosate-resistant Agrostis stolonifera (Poaceae) to compatible relatives. We developed 12 new polymorphic chloroplast microsatellite markers to aid in identifying species recipient of transgenic pollen both within the Agrostis complex and the related genera Polypogon.

Gene flow from herbicide-resistant crops: it's not just for transgenes.

Gene flow was raised as one of the first issues related to the development and release of genetically engineered (GE) crops. Gene flow has remained a topic of discussion for more than 20 years and is still used as an argument against the release of transgenic crops. With respect to herbicide-resistant crops, gene flow does not differ whether the herbicide resistance trait is introduced via genetic engineering or via conventional breeding techniques.

Genetic structure of Aegilops cylindrica Host in its native range and in the United States of America.

Chloroplast and nuclear microsatellite markers were used to study genetic diversity and genetic structure of Aegilops cylindrica Host collected in its native range and in adventive sites in the USA. Our analysis suggests that Ae. cylindrica, an allotetraploid, arose from multiple hybridizations between Ae.

Gene flow from glyphosate-resistant crops.

Gene flow from transgenic glyphosate-resistant crops can result in the adventitious presence of the transgene, which may negatively impact markets. Gene flow can also produce glyphosate-resistant plants that may interfere with weed management systems. The objective of this article is to review the gene flow literature as it pertains to glyphosate-resistant crops.

Investigating the mechanisms of glyphosate resistance in Lolium multiflorum.

Evolved resistance to the herbicide glyphosate has been reported in eleven weed species, including Lolium multiflorum. Two glyphosate-resistant L. multiflorum populations were collected, one from Chile (SF) and one from Oregon, USA (OR), and the mechanisms conferring glyphosate resistance were studied.

Introgression of an imidazolinone-resistance gene from winter wheat (Triticum aestivum L.) into jointed goatgrass (Aegilops cylindrica Host).

Imidazolinone-resistant winter wheat (Triticum aestivum L.) is being commercialized in the USA. This technology allows wheat growers to selectively control jointed goatgrass (Aegilops cylindrica Host), a weed that is especially problematic because of its close genetic relationship with wheat.