Figure 4. NAC089 promotes programmed cell death in plants.

(A–C) Photos of Arabidopsis NAC089D-MYC transgenic lines (XVE089D) and wild-type (wt) control plants transferred to 1/2 MS medium supplied without (A) or with (B) beta-estradiol (BE) for additional 5 days with the quantitative data in (C). (D–E) Caspase 3/7-like activity in protein extracts from NAC089D-MYC overexpression plants treated with BE (D) or in the wt and NAC089 RNAi plants treated with TM (0.5 µg/ml) (E). The caspase-like activity was normalized to the activity of the wt control under normal condition. Bars depict SE (n = 3) in C–E. ** P<0.01, * P<0.05. (F–I) Esterase activities (F–G) and H₂O₂ accumulation (H–I) in the XVE089D-13 roots as revealed by FDA and DAB staining without (F, H) or with (G, I) BE treatment for 3 days. (J–N) Membrane rigidity and nucleus morphology in the XVE089D-13 roots as reflected by PI (J–K) and DAPI (L–N) staining without (J, L) or with (K, M–N) BE treatment for 5 days. (O–Q) DNA breakage in the XVE089D-13 roots as detected by TUNEL assay without (O) or with (P–Q) BE treatment for 5 days. Bar = 10 mm in A–B and bar = 10 µm in F–Q.