Figure 6.
ORE1 but Not ORE1Δ17 Promotes Dark-Induced Senescence.
(A) Senescence phenotypes of plants of the Col-0 wild-type (WT), ore1-1, and the overexpressing lines ORE1-OE and ORE1Δ17-OE. The ORE1Δ17-OE line expresses a mutated ORE1 transcription factor that lacks 17 amino acids encompassing the CPK1-dependent phosphorylation sites. Plants were grown under short-day conditions for 4 weeks. Rosettes were cut and stored in the dark for 4 d on filter papers wetted with distilled water (top). Dark-induced senescence phenotypes of detached mature leaves (bottom). Bars = 4.2 cm (top), 1.7 cm (bottom).
(B) Chlorophyll content of 4-week-old plants treated as in (A, top). Data show means and SDs of three biological replicates, each replicate consisting of a pool of three rosettes. Asterisks indicate a significant difference from Col-0 (wild-type, WT) plants; one-way analysis of variance, Tukey post hoc test; *P < 0.05 (Supplemental Data Set). FW, Fresh weight.
(C) RT-qPCR expression analysis of ORE1, BFN1, and senescence marker gene SAG12, using the reference gene ACTIN2, in plants treated as in (A, top). Relative transcript levels are shown as 2−ΔCt values. Data show means and SDs of three biological replicates, each replicate consisting of cDNA from a pool of three rosettes. Asterisks indicate a significant difference from Col-0 (wild-type, WT) plants; one-way analysis of variance, Tukey post hoc test **P < 0.01; ***P < 0.001 (Supplemental Data Set).