Cross-resistance to dicamba, 2,4-D, and fluroxypyr in Kochia scoparia is endowed by a mutation in an AUX/IAA gene

Significance Because auxin herbicides selectively control broadleaf weeds, their use is extremely valuable in crops, such as wheat and corn. Although auxin-resistant weeds have appeared rarely over the past 60 years of herbicide use, they pose a major challenge in these cropping systems. Several groups have investigated the mechanisms of resistance for several of these weed species; this paper reports the identification of the underlying genetic mechanism of auxin resistance in a field-derived weed species. This mutation sits within a highly conserved region previously identified in Arabidopsis studies as vital for auxin signaling and points to the importance of studies in model systems to predict resistance mechanisms.