Figure 7.

Plants lacking both DEAP2 and PAM68 do not accumulate any functional PSII. A) Plants lacking both DEAP2 and PAM68 (cross of pam68-2 and deap2-1) are only viable on MS medium supplemented with 2% (w/v) sucrose. Pictures (upper panel) and false color maximum photosystem (PS) II quantum yield (Fv/Fm) images (lower panel) of 4-week-old wild type (WT), deap2-1, pam68-2, and pam68-2 deap2-1 double mutants grown at 50 µmol photons m⁻² s⁻¹ and 12 h/12 h dark light cycles. Signal intensities for Fv/Fm were calculated from chlorophyll fluorescence analyses and are given by the false color scale below the panels. B) Immunoblot analysis of total protein extracts from plants as in (A). Samples were fractionated by SDS-PAGE and blots were probed with specific antibodies against DEAP2, PAM68, several subunits of PSII (D1, CP47, CP43, D2, PsbH, PsbI), Cyt b₆f (PetC), PSI (PsaA), and the ATP synthase (AtpC). Ponceau red (P.R.) stained RbcL on the membrane before detection and Actin were used to control for equal protein loading. Numbers left of the immunoblots indicate molecular weight in kDa of protein standards.