Abstract
In the Brassicaceae, compatible pollen grains from same species germinate on the stigmatic papilla cells, while those from unrelated species are largely ignored. The molecules involved in this primary incompatibility (PI) recognition are largely unknown. There can also be an additional layer of recognition to prevent self-fertilization, the self-incompatibility (SI) recognition. It was shown that self-pollen recognition in SI is controlled by the multiallelic gene complex (S-haplotypes) at the S-locus, which contains both female determinant SRK (S-receptor kinase) and male determinant SP11 (S-locus protein 11). SP11 binding to its cognate SRK induces SRK autophosphorylation and initiates a signaling cascade leading to rejection of self-pollen. However, the downstream components involved in this SI signaling are also largely unknown. In order to identify the components involved in PI and/or SI, we performed global gene expression profiling of stigmatic papilla cells. Papilla cells and the beneath style cells were separately collected using laser micro-dissection and comparative cDNA microarray analysis was performed.
