Functional characterisation of the APOSPORY-locus of Hypericum perforatum L.

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Gametophytic apomixis is seed formation without meiotic recombination and reduction (apomeiosis: apospory or diplospory) and without fertilization (parthenogenesis). A molecular understanding of apomictic reproduction is an exiting central problem of plant developmental biology as well as a priority goal of plant breeding aiming at the fixation of hybrid effects. St. John´s wort (Hypericum perforatum L.) is a facultative apomict and represents an unique new experimental system for apomixis research. We have isolated and pre-characterised a genomic region designated as HAPPY locus (Hypericum APOSPORY) strictly co-segregating with apospory, a component of apomixis. The locus includes a gene which encodes a RING finger protein of the ARIADNE type, known to be involved in regulatory processes like the ubiquitin mediated protein degradation. The coding region of the apospory specific allele is distorted and occurs in simplex. Combining molecular techniques such as BAC cloning, marker identification and genetic transformation, the proposed project aims to a detailed structural and functional characterisation of the HAPPY locus in Hypericum peforatum and the reconstruction of the evolutionary history of this region in other apomictic and non-apomictic species in the genus Hypericum.