Figure 2.

Light-dependent phenotype and physiology of AB-I plants. A, Yellow-green (lutescent) leaf phenotype and growth retardation under HL conditions (right). Plants are pictured at the end of the early rosette stage ∼30 days after germination. All molecular genetic and physiological analyses presented in this work were performed at this developmental stage. Bar = 5 cm. B, Analysis of photosynthetic parameters and photooxidative damage. (Left) Quantification of the components of the photosynthetic electron transport chain by difference absorbance spectroscopy. Note that AB-I plants under HL condition are not able to perform a typical light acclimation response by strongly increasing the content of all redox-active components of the electron transport chain relative to LL conditions. Bars represent mean values ± sd (n = 6–8 plants grown alongside). Right: Severe photooxidative damage of AB-I plants under HL conditions, exemplified by measurement of the maximum quantum efficiency of PSII in the dark-adapted state (F_V/F_M). Bars represent mean values ± sd (n = 6–8 plants grown alongside). Different lower case letters indicate significant differences (P < 0.05) according to two-way ANOVA with interactions followed by Tukey’s post-hoc testing (Supplemental File S4). C, Blue-native PAGE independently confirming the reduction of the electron transport chain complexes in AB-I under HL. Protein extracts equivalent to 30 μg chlorophyll were loaded in each lane. This experiment was performed two times independently with similar results.