Mutations in Acetyl-CoA Carboxylase Enzyme, Mechanism of Cross Resistance in Wild Oat (Avena ludoviciana Deuri.) Biotypes to ACCase Inhibitor Herbicides

In order to detect the probability of ACCase inhibitor herbicides target-site based resistance of 13 wild oat (Avena ludoviciana Deuri.) biotypes, molecular experiments were performed using CAPS and dCAPS methods. Biotypes were collected from khuzestan province and which showed cross-resitance to ACCase inhibitors. The above-mentioned molecular methods were used to identify the locations of four important mutations (Isoleucine-2041-Asparagine, Cystein-2088-Arginin, Isoleucine-1781-Leucine and Aspartic acid-2078-Glycine) responsible for target site based herbicide resistance in the carboxyltransferase domain of ACCase enzyme. Both approaches involve DNA extraction, PCR using specific primers and restriction digests of PCR products with restriction enzymes. Results of experiments showed that Isoleucine-1781-Leucine and Aspartic acid-2078-Glycine mutations were observed in 53.8% and 7.6% of resistant wild oat biotypes, respectively. Among the investigated biotypes, only one biotype had two mutations (Isoleucine -1781-Leucine and Aspartic acid-2078-Glycine). Thus, different mutations in the carboxyl transferase domain of ACCase enzyme were the reason of various cross resistance patterns among wild oat biotypes.