Figure 11.

SPL9-DEWAX Is Involved in the Diurnal Regulation of Wax Synthesis.

(A) Diurnal expression of CER1, SPL9, and DEWAX genes in SD (8 h of light/16 h of dark) conditions. Gene expression was analyzed in 9-d-old Arabidopsis wild-type seedlings, which were grown under SD conditions. The light is on at Zeitgeber time 0 (ZT0) and off at ZT8. Total RNA was extracted from each sample (every 3 h from ZT1) and subjected to RT-qPCR analysis. Error bars indicate ±sd with at least three replicates, with each replicate containing at least 20 seedlings.

(B) Cuticular wax amounts of stems from ∼3-month-old wild-type, ProSPL9:rSPL9, spl9-4, dewax, and DXOE plants grown in SD conditions. Cuticular waxes were extracted with hexane and analyzed by GC-FID. Wax coverage is expressed as wax amounts per stem surface area (μg.dm^-2). Error bars indicate ±sd from three replicate experiments with samples independently harvested on different days. Letters denote statistically significant differences between the indicated samples, as determined by ANOVA with post hoc Tukey Honestly Significant Difference.

(C) Total wax loads ratio between SD and LD conditions. Values from plants grown in SD conditions were divided by those from plants grown in LD conditions, and the data were analyzed using Student’s t test (*P < 0.05). Error bars indicate ±sd from biological triplicate experiments.