Figure 3.

Phenotypic studies of pgdh3 mutants reveal alterations in photosynthetic performance. A, 21-d-old WT and pgdh3 mutant plants grown in standard long-day conditions. Mutants do not exert a visual phenotype but (B) show higher NPQ than WT controls. C, Only the loss of the PGDH3 isoform causes increased transient NPQ levels (±se, n ≥ 13 per genotype). D, Overexpression of either PGDH1 or PGDH3 rescues the NPQ mutant phenotype (±se, n ≥ 3 per genotype). E, Comparing transient NPQ kinetics (actinic light intensity: 186-μmol photons m⁻² s⁻¹) of 21-d-old WT and pgdh3 mutant plants shows that in the absence of PsbS transient NPQ is not different between npq4 and npq4pgdh3 loss of function mutants (±se, n = 5 per genotype). F, WT and pgdh3 mutant plants grown under ambient conditions were exposed to fluctuating light (LL, 4 min 90-μmol photons m⁻² s⁻¹; HL, 1 min 900-μmol photons m⁻² s⁻¹) using the Imaging PAM, and chlorophyll-a fluorescence was recorded. Asterisks above and below traces mark when NPQ was significantly increased in both pgdh3 mutant alleles as compared to WT during LL phases (*0.01 < p < 0.05, ***0.001 < p; one-way ANOVA and Tukey pairwise comparison). Traces represent averages extracted from one representative experiment (±se, n = 9 per genotype). The experiment was repeated three times and the same results replicated each time.