Figure 4.

Expression Levels of C4H, CHS, and MYB4 Are Higher in the sad2 Mutant.

(A) to (C) Total RNA was extracted from 12-d-old seedlings of the wild type and the sad2 mutant. The resulting cDNAs were used for real-time PCR analysis. Transcripts of C4H (A), CHS (B), and MYB4 (C) were constitutively higher in sad2-1 than in the wild type. Error bars indicate sd (n = 3).

(C) Real-time PCR analysis shows that MYB4 expression was higher in sad2-2 than in the wild type.

(D) and (E) RNA gel blot analysis of MYB4 expression in the wild type, sad2-1, sad2-2, and two MYB4 overexpression lines. Twenty micrograms of total RNA were probed with MYB4 cDNA. rRNA was used as a loading control.

(F) and (G) Twelve-day-old seedlings of the wild type and an MYB4 overexpression line (F) or the wild type and sad2 (G) were treated with 2 or 3 J/cm² UV-B, respectively (bottom images). Photographs were taken 3 d after transfer to a continuous light growth chamber.

(H) Percentage of bleached cotyledons from seedlings shown in (F) and (G). Vertical bars represent se for three independent experiments.