Identification of genes showing differential expression between morphs in developing flowers of Primula vulgaris

Abstract

Heteromorphic self-incompatibility systems provide an excellent model for studying both intraspecific breeding barriers and the regulation of floral organ size and positioning, yet at the molecular level, they are almost completely uncharacterized. In this study, a subtracted cDNA library was generated from developing and mature floral tissues of the thrum morph of Primula vulgaris, subtracted with the same tissues from the pin morph. Differential screening and reverse transcriptase-polymerase chain reaction analysis identified 11 classes of cDNA that were differentially expressed between developing floral morphs. A number of these classes have significant homology to members of gene families implicated in plant development, including rapid alkalinization factors, DExH box RNA helicases, SKS multi-copper oxidases, and AtCHX ion-transporter families, consistent with their potential involvement in the regulation of floral heteromorphy. None of the cDNAs identified appear to be linked to the Primula S-locus suggesting that they are not components of the S-locus itself, and are more likely downstream components of developmental pathways leading to floral heteromorphy.