Expression data from Arabidopsis wild-type, sicy-192, and sicy-192 gun1-101 plants. Arabidopsis thaliana

Plastid gene expression (PGE) acts as a signal that regulates the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase (INV-E), and showed that following the treatment of this mutant with sucrose, the expression of PhANGs decreased while that of nitrate reductase 1 (NIA1) increased. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment. A double mutant of sicy-192 and gun1-101, a null mutant of GUN1, revealed that metabolic perturbation in the sucrose-treated sicy-192 mutant was, at least in part, dependent on GUN1. To confirm whether there is a relationship between plastid sugar metabolism and nuclear gene expression, we performed a microarray analysis using Suc-treated 3 genotypes consisting of wild-type, sicy-192, and sicy-192 gun1-101 plants. Overall design: Wild-type, sicy-192, and sicy-192 gun1-101 plants were grown on MS medium containing 100 mM sucrose in a growth chamber kept at 25°C during 16 h of light (100 µmol/m2/s) and at 22°C during 8 h of darkness for 4 days. At 4 days of age, cotyledons were collected as samples for microarray analysis.