Screening and identification of genes associated with flower senescence in tree peony (Paeonia x suffruticosa Andrews) using suppression subtractive hybridization

A short blossom period is a major obstacle for the tree peony industry. In order to preferentially isolate genes associated with flower senescence in the tree peony variety ‘Lu He Hong’, forward and reverse suppression subtractive hybridization cDNA libraries were constructed using senescent and blooming petals as testers, respectively. A total of 712 high-quality expressed sequence tags, representing 211 unigenes, were obtained, and 181 unigenes were annotated on the basis of sequence similarity with data in the National Center for Biotechnology Information’s non-redundant database. In addition, 168 unigenes were functionally annotated using Kyoto Encyclopedia of Genes and Genomes databases, and 44 unigenes were classified into 14 functional categories using the Clusters of Orthologous Groups. Most of the unigenes appear to be involved in cellular components, biological processes, and molecular functions, according to Gene Ontology analysis. Analysis of 23 chosen genes using quantitative reverse transcription PCR confirmed that their transcription levels were consistent with the results of the suppression subtractive hybridization libraries.