Fenoxaprop-p-ethyl susceptibility and mutation point detection of acetyl-coa carboxylase (ACCase) in different wild oat (Avena fatua L.) populations from China

To explore resistant mechanism of wild oat to fenoxaprop-p-ethyl, the susceptibility of Acetyl-CoA Carboxylase (ACCase) from 24 wild oat populations to fenoxaprop-p-ethyl, the level of gene expression, and mutation site of ACCase were conducted. In vitro ACCase activities were solated and measured by enzyme-linked immunosorbent assay kit (ELISA) assays, the results indicated that the IC50 value of the ACCase of the most unsusceptible to fenoxaprop-p-ethyl in the wild oat population from Yexian2017 (W24) was 7206.557 -fold compared to that of the ACCase of most susceptible to fenoxaprop-p-ethyl in the wild oat population from Queshan (W11). The differential expression of genes in wild oat treated by the IC50 fenoxaprop-p-ethyl concentration (6.9 mg/L) for 24 hours using RNA-seq, digital gene expression (DGE) profling was conducted. We found that 8 unigenes annotated as ACCase genes, 0 up-regulaed expression and 3 down-regulated expression were observed. The down-regulaed expressed ACCase was selected for qPCR in the relative susceptible population were significantly more suppressed than the three relative resistant populations. The mutations point of ACCase, Ile-1781-Leu, Trp-1999-Cys, Trp-2027-Cys, Ile-2041-Asn, Asp-2078-Gly, Cys-2088-Arg published were not found in the populations tested by multiple sequence alignment with a model complete ACCase sequence of Alopecurus myosuroides. These findings suggest that ACCase plays a critical role in the development of wild oat resistance to fenoxaprop-p-ethyl.