Involvement of miR156b , bHLH069 , and the unknown RNA AT4G30975 in the phenotypes of the sk156 mutant. (A) Transcript levels of bHLH069 in WT (set at 1), sk156, mutant line S468 (SALK_032468), and in sk156 transformants complemented with a 35S:bHLH069 construct relative to WT (set at 1). Insert, schematic of T-DNA insertion site (triangle) in bHLH069 (AT4G30980) in S468 shows above. Exons (black boxes), untranslated regions (light grey boxes), promoter direction (dark arrow). (B) Morphology of 45-d-old transgenic sk156 complemented with 35S:bHLH069. Sk156, and WT plants are also shown. (C) Transcript levels of unknown RNA gene AT4G30975 in WT (set at 1), sk156, and 35S:AT4G30975cDNA-complemented sk156 (A975) plants. Schematic of AT4G30975 expression construct shows above. (D) Morphology of 35-d-old transgenic plant A975 compared to sk156. (E) Transcript levels of miR156 in WT, sk156, and 35S:miR156b-complemented sk156 (T156b) plants. Schematic of 35S:miR156b expression construct shows above. (F) Morphology of 40-d-old transgenic plants from sk156 and 35S:miR156b-over-expressing T156b lines compared to WT. (G) and (H) Seed carotenoid levels in sk156, T156b, A975, S468, 35S:bHLH069/sk156, and WT plants. A Duncan's multiple range test showed significant differences of the means (± standard deviation) compared to WT at p < 0.05. Means containing the same letter for the same compounds are not significantly different.