Gene Expression and Sporophytic Self-Incompatibility in Hazelnut

The European hazelnut (Corylus avellana L.) is a monoeciuos tree and exhibits sporophytic self-incompatibility. Self-incompatibility is a genetic system that prevents the self-fertilization allowing the pistil to reject the pollen of genetically close individuals. Self-incompatibility is controlled by a single multi-allelic locus, the S locus. The involved molecular mechanisms are still partly unknown but in the Brassicaceae. Studies on gene regulation of fertility, pollination and fertilization in hazelnut are very few; so with this research we propose to contribute to the knowledge about the mechanism of sporophytic self-incompatibility in hazelnut. The Differential Display technique was applied for the study of the female determinant of self-incompatibility. Two developmental stages of styles/stygmas were compared: before emergence from the bud and at full bloom. The results allowed to isolate partial sequences that showed an interesting homology degree with transmembrane serine-threonine kinase receptor of Brassica oleracea. Believing that the female determinant of self-incompatibility in hazelnut is very likely a membrane receptor, the efforts for getting differentially expressed sequences of this type were increased. Primers were designed on conserved regions of serine-threonine kinase receptors. Four differentially expressed fragments were isolated from stigmas at full bloom: after blasting in TIGR and NCBI databases, one was homologous to a gene for a kinase receptor, three were homologous to kinase proteins. The isolated sequences are being studied to check their expression in different tissues and style developmental stages.