Identification of differentially expressed genes during flower opening by suppression subtractive hybridization and cDNA microarray analysis in Eustoma grandiflorum

The forward and reverse suppression subtractive cDNA libraries were constructed in petals of Eustoma grandiflorum at bud stage (stage 1) and anthesis (stage 7). Approximately 1000 clones were isolated from stage 1- (S1) and stage 7-specific (S7) libraries. The clones were sequenced and assembled, which yielded 98 contigs and 444 singletons. BLAST search was conducted on these assembled sequences. Generally, probes isolated from the S7 library exhibited higher expression at stage 7 by microarray analysis, as did those of the S1 library at stage 1. A clone set from the S7 library contained genes from later steps of anthocyanin biosynthesis pathway, terpene synthases, GAST (gibberellic acid-stimulated) family proteins, xyloglucan endotransglucosylase/hydrolase, glycosidases, and stress- and senescence-related proteins. In contrast, the S1 library contained genes associated with flavonol biosynthesis, phenylpropanoid metabolism, terpenoid metabolism, and floral organ development. Gene expression profiling for flavonoid biosynthesis was in accordance with preferential accumulation of flavonols at bud stages and anthocyanins at anthesis.