Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Apostart And Serk: Candidate Genes For Apomixis

Emidio Albertini¹ , Gianpiero Marconi¹ , Gianni Barcaccia² , Lorenzo Raggi¹ , Mario Falcinelli¹

¹  Plant Biology and Agro-environmental Biotechnology Department, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy

²  Dipartimento di Agronomia Ambientale e Produzioni Vegetali, University of Padova, Agripolis, Via dell’Università 16, 35020 Legnaro, Padova, Italy

Apomixis is an asexual mode of reproduction through seed that avoids both meiotic reduction and egg fertilization. The essential feature of apomixis is that an embryo is formed autonomously by parthenogenesis from an unreduced egg of an embryo sac generated trough apomeiosis. If apomixis were well understood and harnessed, it could be exploited to indefinitely propagate superior hybrids or specific genotypes bearing complex gene sets. A fundamental contribute to the understanding of the genetic control of the apomictic pathway could be provided by a deep knowledge of molecular mechanisms that regulate the reproductive events. We applied the cDNA-AFLP method of mRNA profiling to developmentally staged inflorescences of P. pratensis and visualized a total of 2,248 TDFs, 179 of which were differentially expressed between apomictic and sexual genotypes of Poa pratensis at the time of flowering when the primary stages of apomixis occur. Of the about 8% of mRNAs differentially expressed between apomictic and sexual genotypes, the vast majority were attributable to genes with a differentiated temporal expression during flowering. As few as 1.6% mRNAs specific to sexual or apomictic genotypes were found, providing that a highly conserved developmental program exist in embryos during zygotic embryogenesis and apomeiotic parthenogenesis. Here we report two of these genes, APOSTART and PpSERK. Their genomic organization and characterization through temporal expression analysis of transcripts in reproductive tissues are reported. The putative involvement of these two genes in the process of ovule development, and somatic embryo induction is discussed.