Characterization of DYAD orthologs in apomict Boechera holboellii

Here we report the structure and expression patterns of orthologs for DYAD gene in the apomict Boechera. The DYAD cDNAs were obtained by RT-PCR from Boechera flower buds. Dyad is a mutant allele of SWI1 gene characterized as a required gene for meiotic chromosome organization and female meiotic progression in Arabidopsis. DYAD gene causes formation of two diploid cells instead of expected 4 haploid gametes. It is reported that this function of DYAD gene leads to functional apomeiosis in Arabidopsis thaliana. Apomixis is a reproduction way which creates genetically identical seeds with the maternal plant and it will enable the clonal reproduction of hybrids when it is achieved in culture plants. Sexual reproduction is a process involves gametes formed by meiosis and double fertilization. However in apomictic process, many of these steps are either bypassed or modified. In apomict species; chromosome number in male and female gametes are not reduced (apomeiosis), nevertheless embryo sac and pollen formation continues. Furthermore, the apomeiotic egg cell spontaneously forms the embryo (parthenogenesis). Therefore, apomixis leads to clonal reproduction by seeds. Although, introduction of apomixis from natural apomicts to culture plants haven?t been achieved by hybridization methods. In this work, sturcture of DYAD gene which leads A. thaliana plants to apomeiosis is investigated with RT-PCR method in apomict plants for the first time. We have isolated a 1243 bp long transcript of DYAD gene in Boechera showed high similarity with Arabidopsis thaliana DYAD. Phylogenetic analysis revealed six similar protein sequences from various species.