Gene expression in the rcb (regulator for chloroplast biogenesis) mutant in red light conditions

The regulator for chloroplast biogenesis (rcb) mutant was identified as a mutant defective in phytochrome-mediated chloroplast biogenesis. The rcb mutant has long hypocotyl and albino phenotypes. RCB initiates chloroplast biogenesis in the nucleus by promoting the degradation of the master repressors for chloroplast biogenesis, the PIFs (Phytochrome Interacting Factors). To understand how RCB regulates the expression of PIF-regulated genes, we performed genome-wide expression analysis of RCB-dependent genes using a rcb-10 null allele. Wild-type (Col-0) and rcb-10 mutant seeds were surface-sterilized and plated on half-strength Murashige and Skoog (MS) growth medium without sucrose. After 4 days of stratification in the dark at 4ºC, seedlings were grown in 10 μmol m-2 s-1 R light.