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Analysis of glutamine synthetase target-site mutations and their role in endowing glufosinate-ammonium resistance
(Wiley, 2025-11)
Porri, Aimone
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Sudhakar, Susee
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Noguera, Matheus M.
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Betz, Michael
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Lerchl, Jens
BACKGROUND. Glufosinate-ammonium (GFA) is a non-selective herbicide that inhibits glutamine synthetase (GS), a key enzyme in plant nitrogen metabolism. Although resistance to GFA has been reported in several weed species, confirmed cases of target-site resistance (TSR) via GS mutations remain rare. In Amaranthus palmeri, resistance is usually associated with GS gene amplification and overexpression, while the role of GS point mutations remains unclear. This study investigated GFA resistance in a population lacking GS amplification, and evaluated the functional relevance of putative resistance-conferring GS mutations. RESULTS. Digital PCR revealed no substantial GS amplification or overexpression in the CCR population. Sequencing identified a glycine-to-aspartic acid substitution at position 255 (G255D) in the chloroplastic GS2.2 isoform, detected in ~80% of CCR plants in heterozygous form. Notably, this mutation was exclusively in untreated plants. In vitro assays showed that GS2.2 G255D retained ~58% of wild-type catalytic activity and was completely insensitive to GFA inhibition. However, ectopic expression of G255D, as well as the homologous Arabidopsis GS2.2 G254D substitution, did not confer GFA tolerance in Arabidopsis. Analysis of GS1.1 variants demonstrated that mutations disrupting GFA binding generally caused severe reductions in catalytic efficiency. Re-evaluation of the previously reported Eleusine indica GS1.1 S59G mutation revealed no meaningful shift in GFA sensitivity. CONCLUSIONS. GFA resistance in the CCR population cannot be explained by GS amplification or GS2.2 G255D. These findings underscore the strong structural and functional constraints on GS target-site evolution and suggests that non-target-site mechanisms likely underlie GFA resistance in this population. © 2026 BASF SE and The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
N-terminal Rht-A1 mutations modify spring wheat (Triticum aestivum L.) plant height
(Wiley, 2026-03)
Hale, Caleb O.
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Urgin, Josey M.
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Volkman, McKenna M.
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Tracy, Emma M.
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Martin, John M.
The Reduced Height-1 (Rht-1) gene in wheat (Triticum aestivum L.) has been well studied since the introgression of semidwarfing alleles Rht-B1b and Rht-D1b into many wheat varieties in the mid-20th century. Rht-B1b and Rht-D1b increase plant productivity but also reduce single grain weight and protein content. Other alleles of Rht-1 as well as other height-affecting genes have been studied to provide breeders with alternative ways to modify plant height. To find Rht-A1 alleles that could be used to fine tune plant height and other phenotypic traits that are affected by Rht-1, an ethyl methanesulfonate mutagenized Alpowa spring wheat population was screened for Rht-A1 N-terminal mutations. Nine mutations were identified and characterized through yeast two-hybrid experiments to measure the impact each mutation had upon interaction with the gibberellin receptor GID1. Near isogenic lines were created by backcrossing the nine alleles into the cultivars Vida and Duclair, both with and without the semidwarfing allele Rht-B1b, and tested in preliminary spaced-plant trials. Five of these Rht-A1 alleles (including a nonsense mutation allele, Rht-A1-Q6*) were selected for inclusion in full density yield trials. Only one mutant allele, Rht-A1-E63K, consistently decreased height across tested backgrounds. This included a height decrease of 6 cm and a yield increase of 12% in a “tall” background when no other height reducing alleles were present. The Rht-A1-E63K mutation occurs within the LExLE motif where Rht-B1b and Rht-D1b mutations also occur, emphasizing the importance of this locus to the function of Rht-1.
An observational study of the temporal dynamics of natural Mycoplasma (Mesomycoplasma) ovipneumoniae infection in a range flock of domestic sheep (Ovis aries)
(American Veterinary Medical Association, 2026-03)
Quirk, McKenna D.
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Jacobson, B. Tegner
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Sonar, Sobha
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Schaub, Daniel
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Collins, Macy J.
Objective. To characterize the dynamics of Mesomycoplasma ovipneumoniae colonization and serum antibody responses in a rangeland flock of domestic sheep (Ovis aries). Methods. A cohort of 40 female lambs was repeatedly tested for M ovipneumoniae from birth to 25 months of age. Nasal swabs were analyzed for M ovipneumoniae infection by PCR, and a competitive ELISA was utilized to determine antibody levels. Body weights and body condition scores also were determined. Results. M ovipneumoniae infection was rapidly acquired, with 80% of the study animals testing PCR positive at 2 months of age and 96.2% testing PCR positive at 4 months of age. The PCR positivity rate then fluctuated between 35% at 10 months and 94% at 25 months. Antibody levels expressed as percentage of inhibition were 57.9% in the dams and 52.7% in their offspring within 24 hours after birth, fell to 18.7% in the lambs at 2 months, and then remained variable, ranging from 36% to 64.2%. No significant association between M ovipneumoniae colonization and antibody levels or daily weight gains was found. Conclusions. In a flock with high M ovipneumoniae infection rates, infections were acquired early in life and then fluctuated over time with no clear trends. Importantly, the serum antibody responses that we measured did not appear to enable sustained pathogen clearance. Clinical Relevance. Our study indicates that, once infected, sheep do not develop effective sterilizing immunity to M ovipneumoniae, and serum antibodies cannot be considered a reliable correlate of protection in individual sheep.
Community-Engaged Approach to Increase Physical Activity Among Black Individuals With Colorectal Cancer: Protocol for a Feasibility Randomized Controlled Trial of the Physical Activity Centers Empowerment Study
(JMIR Publications Inc., 2025-06)
Hirschey, Rachel
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Xu, Jingle
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Woodard, Nathaniel
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Duggins, Paulette
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Lea, Deirdre F.
Background: Black individuals are more likely to die from colorectal cancer (CRC) and experience more treatment-related side effects compared to White individuals. Physical activity (PA) has been associated with decreased side effects, improved CRC treatment completion rates and responses, and survival. However, Black survivors of CRC are 60% less likely to engage in PA than White survivors. The Physical Activity Centers Empowerment (PACE) study is testing an intervention specifically designed to increase PA among Black individuals diagnosed with CRC. Objective: This study outlines the protocol for a randomized controlled trial. The study aims to test the feasibility of PACE and will use the reach, effectiveness, adoption, implementation, and maintenance (RE-AIM) framework. Methods: The PACE study was developed in partnership with a community advisory board consisting of Black cancer advocates and survivors of cancer. The study aims to recruit 72 participants aged >18 years from North Carolina who have been diagnosed with CRC. These participants will be randomized in a 1:1 ratio to an intervention or control group. During the 12-week intervention, all participants will receive a wearable activity tracker and informational materials from the American College of Sports Medicine’s “Moving through Cancer” program. The intervention group will also receive additional PACE theory–guided intervention components, including personalized daily adaptive step goals, access to the PACE video library, and optional video chat meetings for PA support. Data will be collected at 3 time points: baseline, after the intervention (3 months), and 6 months after the intervention (9 months). Using the RE-AIM framework, the study aims to evaluate the intervention’s reach, effectiveness, acceptability, implementation, and maintenance. Results: The National Institute on Minority Health and Health Disparities funded this study in 2021. Study enrollment began in August 2024 and is anticipated to conclude in December 2024. Conclusions: This study will advance our understanding of effective behavioral strategies to increase PA and help advance the use of PA as a form of complementary cancer treatment, with the aim of improving health outcomes for Black survivors of CRC.
Shear zone reactivation during multiple phases of Proterozoic orogeny: evidence from in situ monazite dating of the Slide Lake Shear Zone, Colorado
(Geological Society of London, 2025-12)
Leierzapf, Jeremy
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Jessup, Micah J.
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Grambling, Tyler A.
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Shaw, Colin A.
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Allen, Joseph L.
Shear zone systems exposed in the crystalline rocks of Colorado record Proterozoic deformation episodes documenting strain partitioning, reactivation and the progressive tectonic evolution of SW Laurentia. These structures, and their equivalents throughout the southwestern USA, provide insight into the structural evolution of the North American craton, and inform tectonic models for an active, but challenging to decipher period in Earth's history. NE–SW-trending mylonitic bands record regional fold formation and establishment of sub-vertical D1/D2 shear zones occurred during the successive c. 1720–1600 Ma Yavapai and Mazatzal orogenies, and D3/D4 reactivation of these structures during the c. 1450–1300 Ma Picuris Orogeny. The shallowly dipping Slide Lake Shear Zone (SLSZ), in Colorado's Sawatch Range, is adjacent to the steeply dipping Homestake Shear Zone (HSZ), allowing for comparison between high- and low-angle faulting in mid-crustal positions associated with the long-lived Laurentian orogenic margin throughout the Proterozoic. Both structures record similar deformational conditions and bulk NW–SE-verging kinematics. Newly obtained in situ electron microprobe monazite U–Th–Pb geochronology and trace element geochemistry constrain the timing and nature of SLSZ activity, allowing direct comparison with established HSZ activity. Core domains in a steeply dipping segment of the SLSZ record mineral growth during the Yavapai Orogeny (D1) at c. 1700 ± 14 Ma, and support continued SLSZ activation during the Mazatzal Orogeny (D2). Low-angle segments preserve deformation associated with the Mesoproterozoic Picuris Orogeny (D3/D4) at c. 1450–1300 Ma. The age progression of the SLSZ parallels the structural evolution of the HSZ, indicating that sub-horizontal, transtensional, D3/D4 slip on the SLSZ was coeval with sub-vertical, transpressional, D3/D4 slip on the HSZ. Cumulatively, the existing structural and newly established temporal history of the HSZ–SLSZ system is interpreted to indicate that oblique extensional and compressional strain were competing in the middle crust within the Laurentian interior during the Picuris Orogeny, lending credence to models of plateau-style crustal thickening and collapse during this event.