atgcn1-1 and atgcn1-2 are sensitive to the herbicide chlorsulfuron. (a) The atgcn1-1 and atgcn1-2 mutants displayed higher sensitivity to chlorsulfuron than the wild type. MS, MS medium; MS + chlorsulfuron, MS medium supplemented with chlorsulfuron; MS + chlorsulfuron + aa, MS medium supplemented with chlorsulfuron and amino acids including isoleucine, leucine, and valine. (b) Quantification of yellow plants induced by chlorsulfuron. t-tests were performed between atgcn1-1, atgcn1-2 and the wild type (gl1 background). Double asterisks indicate p <0.01. (c) Immunoblotting assay shows the phosphorylation level of eIF2α in atgcn1-1 after chlorsulfuron treatment.