Pro197 and Trp574 substitutions in the acetolactate synthase of corn marigold (<i>Glebionis segetum</i>) and their impact on competitive ability against barley

Abstract Three suspected resistant (R1, R2, and R3) corn marigold populations collected from winter cereal fields located in central Greece were studied to confirm elucidate the mechanisms of resistance acetolactate synthase (ALS) inhibitors their competitive ability against barley. Whole-plant dose–response assays proved that three R highly cross-resistant ALS tribenuron, pyroxsulam + florasulam, imazamox, whereas control with synthetic auxin plus co-formulated mixtures was increased order tritosulfuron dicamba &lt; florasulam clopyralid tribenuron mecoprop-P aminopyralid. The gene sequence revealed a point mutation 11 plants R1, R3 populations, which resulted substitution Pro-197-Thr or Trp-574-Leu. By contrast, all sequenced susceptible (S) population found wild-type allele encoding Pro-197 Trp-574. This is first report ALS-inhibitor marigold. competition study between barley four densities S, indicated similar biomass rates for suggesting lack association target-site mechanism, also confirmed by reduction grown S populations.