Figure 1.

FLU-Dependent Regulation of Pchlide Synthesis in Arabidopsis.

(A) FLU has been identified as a membrane-bound plastid protein that mediates the feedback control of chlorophyll synthesis (Meskauskiene et al., 2001). As indicated by the question marks, it is not known whether Pchlide acts in its free form or as part of the ternary POR-Pchlide-NADPH complex as an effector of feedback inhibition. ALA, δ-aminolevulinic acid; Chlide, chlorophyllide.

(B) and (C) Pchlide accumulation in dark-adapted, mature wild-type (wt) and flu plants. Plants were grown under continuous light until they were ready to bolt. At this developmental stage, plants were transferred to the dark for the first time. After 8 h, total porphyrins (B) or nonesterified porphyrins (C) were extracted. The fluorescence emission spectra of these samples were recorded using an excitation wavelength of 433 nm.