SOC1 is a negative regulator of Chl degradation. A, Attached leaves of soc1-6 exhibited an accelerated yellowing phenotype during dark treatment. Three-week-old plants were treated in darkness for 7 d before being photographed. B, Chl contents in the fifth and sixth rosette leaves of the plants shown in A. C, Ratios (dark-untreated) of PPH transcript levels in the fifth and sixth rosette leaves of the plants shown in A. D, Detached leaves of soc1-6 exhibited an accelerated yellowing phenotype during dark treatment. Detached fifth and sixth rosette leaves of 3-week-old plants were treated in darkness for 5 d. E, Chl contents in the detached leaves shown in D. F, Ratios of PPH transcript levels after dark treatment over those in the untreated leaves shown in D. G, Induced overexpression of SOC1 (iSOC1-OE) resulted in a partial stay-green phenotype during dark treatment. Detached fifth and sixth rosette leaves of 3-week-old plants were treated in darkness for 6 d. Mock, Water; DEX, 30 µm
DEX water solution; vector, empty vector control. H, Chl contents in the detached leaves shown in G. I, Ratios of PPH transcript levels after dark treatment over those in the untreated leaves shown in G. Data are means ± sd of three biological repeats. ***, P < 0.001 (Student’s t test). FW, Fresh weight.