Global gene expression analysis of normal and ripening inhibitor (rin) mutant tomatoes during ripening

Ripening is an important stage of fruit development to determine its quality as a diet. A tomato (Solanum lycopersicum) MADS-box transcription factor, RIPENING INHIBITOR (RIN), has been believed to serve as a regulator of ripening lying upstream of ethylene-dependent and ethylene-independent pathways. Here, we have conducted global gene expression analysis to comprehensively identify tomato genes whose expressions are affected by the rin mutation using microarray with RNA samples from the normal and rin mutant tomato fruits at the pre-ripening (mature green) and ripening (pink coloring) stages. By analysing this microarray data, we identified 342 of positively regulated and 473 negatively regulated genes by RIN, which showed >5 and <0.2 of the fold change ratio (FC) of normal fruits at the ripening stage relative to those at the pre-ripening stage, respectively, in a RIN-dependent manner. A chromatin immunoprecipitation (ChIP) analysis of the normal ripening tomatoes with the anti-RIN antibody revealed that the positively regulated gene set contained at least 13 direct RIN targets. We monitored global gene expression in normal (PK331 cultivar) and rin mutant (PK353 cultivar) tomatoes at the pre-ripening (mature green, G) and ripening (pink coloring, P) stages using microarray with three biological replicates for each sample.