Figure 5.

BBX31 promotes the accumulation of UV protective compounds under high doses of UV-B light. A, Representative images of Col-0 and bbx31-1 seedlings as well as Col-0 and three overexpression lines of BBX31 (35S:BBX31#1, 35S:BBX31#2, and 35S:BBX31#3) grown in WL (long day, 16 h/8 h) for 5 d and then given continuous UV-B light (4.5 W m⁻²) for 19 d. B, Total chlorophyll content of the seedlings shown in A. C, Anthocyanin quantification for 5-d-old seedlings grown in WLc (10 μmol m⁻² s⁻¹) supplemented with UV-B light (1.4 W m⁻²). Fw, Fresh weight. D, Quantification of the phenolic compounds coumaric acid, gallic acid, hydroxybenzoic acid, and vanillic acid extracted from 2-week-old Col-0 and 35S:BBX31 seedlings treated with continuous UV-B light (4.5 W m⁻²) for 24 h and analyzed using GC-MS. For B to D, three replicates were taken for quantification analysis, and all of them showed similar data. Error bars represent sd of three replicates. Unpaired Student’s t test was performed to check significance. Asterisks represent statistically significant differences (***, P < 0.001; **, P < 0.01; and *, P < 0.05) as determined by Student’s t test; ns, nonsignificant.