Identification and characterization of genes differentially displayed in Rosa hybrida petals during flower senescence

The useful life of the flower is terminated by senescence which is a well regulated process that involves structural, biochemical and molecular changes. cDNA–AFLP was used under stringent PCR conditions to identify transcripts that are strongly expressed during petal senescence of two cut rose cultivars, ‘Black magic’ and ‘Maroussia’, with different longevities, 5.6 and 14.3 days vase life, respectively, and at different (2 and 8) stages of flower opening. Five transcripts from 35 isolated fragments which showed clear variation in the presence/absence between two cultivars were screened. Sequence comparison of these cDNAs revealed 44% similarity to the genes encoding DNA helicase in Arabidopsis thaliana, others to the translation initiation factor IF-1 and -d-galactosidase in apple and arabinogalactan protein in petunia. The expression patterns of these genes were analyzed by real-time RT-PCR and it was found that most of them were up-regulated and one other was down-regulated in both cultivars during senescence.