Identification of ovule transcripts from the Apospory-Specific Genomic Region (ASGR)-carrier chromosome

Apomixis, asexual seed production in plants, holds great potential for agriculture as a means to fix hybrid vigor. Apospory is a form of apomixis where the embryo develops from an unreduced egg that is derived from a somatic nucellar cell, the aposporous initial, via mitosis. Understanding the molecular mechanism regulating aposporous initial specification will be a critical step toward elucidation of apomixis and also provide insight into developmental regulation and downstream signaling that results in apomixis. To discover candidate transcripts for regulating aposporous initial specification in P. squamulatum, we compared two transcriptomes derived from microdissected ovules at the stage of aposporous initial formation between the apomictic donor parent, P. squamulatum (accession Ps26), and its apomictic derivative backcross 8 (BC8) containing a single P. squamulatum chromosome. Toward this end, two transcriptomes derived from ovules of an apomictic donor parent and its apomictic backcross derivative at the stage of apospory initiation, were sequenced using 454-FLX technology. 332,567 reads with an average read length of 147 base pair were generated for the Ps26 ovule transcriptome library and 363,637 reads with an average read length of 142 base pair were generated for the BC8 ovule transcriptome library