Modem agriculture is faced with the challenge of feeding a rapidly growing population.While crop yields have risen dramatically since the beginning of the twentieth century,increasing demand for food threatens to outstrip the pace of agricultural progress.While significant research continues to focus on strategies that directly maximize crop yield,another important research area is the minimization of yield loss to weeds,insects,diseases,and abiotic stresses.Crop yield losses due to weeds can reach above 34％,the highest potential loss of any biotic factor (Oerke,2006).The use of herbicide-resistant crops is an important tactic for effectively minimizing these losses.However,continued reliance on major herbicide-resistant traits has resulted in issues that threaten to undermine the effectiveness of the technique,in particular,the popularity and dominance of glyphosate-resistant “Roundup Ready”crops have led to the emergence of numerous glyphosate-resistant weed species (Heap,2014),widespread environmental contamination with glyphosate and its major degradation product (Battaglin et al.,2014),and public conces about health risks associated with glyphosate exposure.The other major herbicide-resistant trait,BAR,which confers glufosinate resistance,was recently shown to exhibit off-target effects on plant metabolomes (Christ et al.,2017),raising the urgency to develop new and better herbicide-resistant traits for crop use.