Fig. 5

MdDEP1 attenuates PSI activity in apple leaf cells. A. Induction and relaxation of NPQ monitored during dark-to-light transition (120 μmol photons m^− 2 s^− 1). Curves represent an average of six independent measurements. B. Re-reduction of P₇₀₀⁺ in darkness. P₇₀₀ was oxidized by illumination of the leaf with far red (FR) light for 30 s and after termination of FR illumination, P₇₀₀⁺ re-reduction was monitored in darkness. Curves, representing an average of six independent measurements, are normalized to the same amplitude for direct comparison of the kinetics. C. Immunoblot assays of PS I core protein subunits PsaA, PsaD, and PsaF, and PS II reaction center protein D1. An anti-MdDEP1 antibody was used to detect MdDEP1 and an anti-ACTIN antibody was used as a control. Note: Protein bands were quantified by scanning densitometry using a Hewlett Packard scanjet scanner and Scanplot software. D. Accumulation of PSI complexes in the WT and three MdDEP1 transgenic apple plantlets. Thylakoids were isolated at the end of the dark period, solubilized with digitonin and protein complexes were separated by large pore blue native analysis. Gels were loaded on Chl basis. PSI complexes were identified by second dimension (BN-PAGE). A representative example from three independent biological replications is shown