Identification of genes associated with perianth senescence in Daffodil (Narcissus pseudonarcissus L. 'Dutch Master')

We used a PCR-based subtractive procedure to isolate genes that increased in abundance in the perianth of incipiently senescent daffodil (Narcissus pseudonarcissus L. 'Dutch Master') flowers. Using RNA gel blot analysis we confirmed that 18 of the transcripts were senescence-associated. A number of these have homologs in previously-studied senescing floral and leaf tissue systems (cysteine proteases, serine proteases, endonuclease, vacuole processing enzyme). Some showed homology to genes encoding proteins with transport functions (auxin efflux carrier protein, low affinity nitrate transporter), others to enzymes that may have a role in cellular signaling (RSH-like protein). A surprising number of the isolated genes either showed no homology with previously-reported sequences or were sequences with no known function. A strong association of some of the transcripts with senescence was also indicated by their enhanced accumulation in the perianth of detached daffodil flowers, which senesce earlier than attached flowers. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.