Extended Data Fig. 8: Constitutively active MKK9 inhibits CS formation via suppressing MYB36.

(a) CASP1-GFP and corresponding MYB36 accumulations in sgn3 CASP1-GFP indMKK9a transformed with MYB36^WT-GFP, MYB36^AAA-GFP, MYB36^DDD-GFP with or without EST induction. CASP1-GFP overviews from different plant lines at mature CS stage (16-17^th cell) are shown in upper panels. Nuclei signals of MYB36-GFP from the same lines are taken around the onset of CASP1-GFP (7-8^th cells) and shown in corresponding panels below. GFP signals are shown in gradient intensity. Scale bars = 20 µm. (b) Immunoblots (IB) against anti-FLAG show accumulations of the C-terminally 3xFLAG tagged indMKK9a in sgn3 CASP1-GFP (T3 homozygous for MKK9a) transformed with MYB36^WT-GFP, MYB36 ^AAA-GFP, MYB36^DDD-GFP with and without EST induction. Seedling roots of the same T2 lines used in Fig. 6a–d were grown on DMSO or 5 µM EST. Loading controls: IBs with anti-Actin antibody. Numbers above each lane show the FLAG (MKK9a) intensity normalized to corresponding Actin loading control. ‘>’ indicate MKK9a, ‘n.s.’ indicate non-specific bands. See Supplementary Fig. 7 for uncropped original blots. Due to limited seed material, this experiment could only be performed once.