Figure 6.

BBX31 promotes UV-B tolerance in a HY5-dependent manner. A, Recovery assay with Col-0, hy5, 35S:BBX31, and hy5/35S:BBX31 lines. Seedlings were grown for 7 d under WL and then irradiated for 24 h with UV-B light (1.4 W m⁻²). Treated seedlings were further grown for 4 d under WL (long day, 16 h/8 h) conditions without UV-B light to induce recovery before taking the image. B, Total chlorophyll content in the indicated genotypes measured in WL and after the UV-B treatment as in A. C, Transcript levels of ELIP1, ELIP2, CHS, CHI, and UVR2 in the indicated genotypes in WL and after 1 h of UV-B treatment. The fold changes in all other genotypes were calculated relative to Col-0 in WL. D, Recovery assay with Col-0, hy5-215, bbx31-1, and hy5-215 bbx31-1 lines (same experimental conditions as in A). E, Total chlorophyll content of the indicated genotypes shown in D. F, Transcript levels of ELIP1, ELIP2, CHS, CHI, and UVR2 in the indicated genotypes in WL and after 1 h of UV-B treatment. The fold changes in all other genotypes were calculated relative to Col-0 in WL. Asterisks in B and E represent statistically significant differences (***, P < 0.001; **, P < 0.01; and *, P < 0.05) as determined by two-way ANOVA followed by Bonferroni posttests; ns, nonsignificant. Error bars in all graphs represent sd of three replicates.