Joann Conner

As an Associate Research Scientist in the Horticulture Department & Institute of Plant Breeding, Genetics and Genomic at the UGA-Tifton campus, my research interest is to identify the gene/genes responsible for apospory and to determine if these apomixis gene(s) can be transferred to and function in non-apomictic food crops. Apomixis is a naturally occurring mode of asexual reproduction in angiosperms that leads to embryo and seed formation without a requirement for meiosis or fertilization of the egg. Multiple forms of apomixis (apospory, diplospory and adventitious embryony) are widespread across angiosperms. The ability to introduce apomixis in food crops could significantly alter agricultural practices by effectively harnessing hybrid vigor as any obligate apomictic plant, even when highly heterozygous, will breed true for its genotype. Apomixis could effectively be used in breeding programs because of its ability to be transmitted through paternal gametes but then subsequently would fix hybrid genotypes through the clonal maternal seed. Because current crop species are not apomictic, we are studying apomixis in the wild species Pennisetum squamulatum and Cenchrus ciliaris, members of the grass family that are closely related to Pennisetum glaucum (pearl millet). In P. squamulatum, apomixis is transmitted along with a specific chromosomal region, the apospory-specific genomic region (ASGR), which is delineated by a ~50 Mb large telomeric portion of a chromosome arm. Current research to identify the gene/genomic sequences required for apomixis include a) the characterization of a candidate apomictic gene for parthenogenesis, the PsASGR-BabyBooM-like gene from Pennisetum squamulatum through the generation of transgenic lines, b analysis of deletion plant312 which carries a portion of the ASGR-carrier chromosome unlinked to the ASGR, c) transcriptome analysis from both early stage ovules and late stage ovules from P. squamulatum, BC8 apomictic and BC8 sexual plants to identify global gene expression differences as well as identifying ASGR chromosome linked transcripts, and d) identification and analysis of plant A8 which underwent a recombination event within the ASGR genetic loci and that has separated the 2 components of apomixis, apomeiosis and parthenogenesis.