ABSTRACT
Green foxtail [Setaria viridis (L.) P.Beauv.] is a troublesome grass weed that is widely distributed in maize (Zea mays L.) fields across China. Many populations of S. viridis have evolved resistance to the acetolactate synthase (ALS)-inhibiting herbicide nicosulfuron. The objectives of this research were to confirm nicosulfuron resistance in these populations and to investigate the basis of nicosulfuron resistance. Whole-plant dose-response experiments showed 6 out of 13 S. viridis populations were highly resistance (20-30 times) to nicosulfuron. Sequencing of the ALS gene revealed two amino acid mutations, Asp-376-Glu and Pro-197-Ala, in the nicosulfuron-resistant populations. A malathion pretreatment study revealed that the R376 and R197 subpopulations might have cytochrome P450s-mediated herbicide metabolic resistance. The resistant populations were cross-resistant to imazethapyr but sensitive to topramezone and quizalofop-p-ethyl. This is the first report of resistance to ALS inhibitors conferred by target site mutations (Asp-376-Glu or Pro-197-Ser) and possible cytochrome P450s-involved metabolism in S. viridis.
Subject(s)
Acetolactate Synthase , Herbicides , Setaria Plant , Acetolactate Synthase/genetics , Cytochrome P-450 Enzyme System/genetics , Herbicide Resistance/genetics , Herbicides/pharmacology , Mutation , Pyridines , Sulfonylurea CompoundsSubject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Bone Diseases, Metabolic/prevention & control , Hip Joint/drug effects , Lumbar Vertebrae/drug effects , Absorptiometry, Photon , Adalimumab , Arthritis, Rheumatoid/blood , Arthritis, Rheumatoid/complications , Arthritis, Rheumatoid/diagnosis , Biomarkers/blood , Bone Density/drug effects , Bone Diseases, Metabolic/blood , Bone Diseases, Metabolic/diagnosis , Bone Diseases, Metabolic/etiology , Case-Control Studies , Collagen Type I/blood , Hip Joint/diagnostic imaging , Hip Joint/metabolism , Humans , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/metabolism , Peptides/blood , Severity of Illness Index , Time Factors , Treatment OutcomeABSTRACT
Because of the rapid development of transgenic maize, the potential effect of transgene flow on seed purity has become a major concern in public and scientific communities. Setting a proper isolation distance in field experiments and seed production is a possible solution to meet seed-quality standards and ensure adventitious contamination of products is below a specific threshold. By using a Gaussian plume model as basis and data recorded by meteorological stations as input, we have established a simple regionally applicable maize gene-flow model for prediction of the maximum threshold distances (MTD) at which gene-flow frequency is equal to or lower than a threshold value of 1 or 0.1 % (MTD1%, MTD0.1%). After optimization of the model variables, simulated outcrossing rate was a good fit to data obtained from field experiments (y = 1.156x, R (2) = 0.8913, n = 30, P < P 0.01). In the process of model calibration, it was found that only 15.82 % of the total amount of the pollen released by each plant participated in the dispersal process. The variable "a" for genetic pollen competitiveness between donor and recipient was introduced into our model, for the "Zinuo18" and "Su608" used, "a" was 17.47. Finally, the model was successfully used in the spring maize-growing region of Northeast China. The range of MTD1% and MTD0.1% in this region varied from 10 m to 49 m and from 17 m to 125 m, respectively.
