The SHR-PHB pathway and cytokinin signaling.

(A) Cytokinin (CK) expression in wild-type, shr, and shr phb roots. tZ, Transzeatin; tZR, tZ Riboside; iP9G, N⁶-(Δ²-isopentenyl) adenine-9-glucoside; tZ9G, tZ-9-glucoside. (B) Expression of pTCS:GFP in wild-type, shr, and shr phb roots. (C) Real-time PCR and ChIP showing PHB binding to the ARR7 promoter. Line diagram represents the ARR7 promoter region. Arrows and blue bars indicate primers and B-ARR binding elements (GGATT/AATCT), respectively. (D) Recovery in pAHP6:erGFP expression in the shr phb roots in comparison with shr roots. The error bars represent the standard deviation (A) and standard error (C) (n = 3 biological replicates). Scale bars: 25 μm. CK, cytokinin.