P0341 Eps-Am1, A Locus Regulating Reproductive Development in Triticum monococcum, Has Been Delimited to a 50 kb Region Including Two Genes

Maria Alejandra Alvarez , University of California, Davis, CA
Maria Elena Faricelli , University of California, Davis, CA
Silvina Lewis , Instituto de Recursos Biológicos, INTA, Argentina
G Tranquilli , Instituto de Recursos Biológicos, INTA, Argentina
Maria Laura Appendino , Cátedra de Genética, Facultad de Agronomía, Universidad de Buenos Aires, Argentina
Jorge Dubcovsky , University of California, Davis, CA
Earliness per se genes regulate flowering time independently of vernalization and photoperiod, and are important for the fine tuning of wheat heading time. The earliness per se gene Eps-Am1 was mapped on the long arm of chromosome 1AmL of diploid wheat Triticum monococcum. The Eps-Am1-l allele from cultivated accession DV92 significantly extends the duration of spike development, increasing the number of spikelets per spike relative to the allele of the wild accession G3116. As part of our efforts to clone this gene, we constructed a high-density genetic map and a physical map of the Eps-Am1 region. We generated a population including ~4,500 segregating lines (~9,000 gametes) and delimited a 0.06 cM region including Eps-Am1, flanked by genes CtE1 and Adk1. We screened a T. monococcum DV92 BAC library and constructed a physical contig of ~300 kb including Eps-Am1 flanking markers. Sequencing of this contig revealed the presence of 3 additional genes: Fop1, Mot1 and FtsH4. Development of additional markers in this region and progeny tests of the Eps-Am1 closest recombination events established that this earliness per se gene is completely linked to genes Mot1 and FtsH4. These results were confirmed using F2 progeny of the cross between two T. monococcum accessions carrying contrasting alleles of Fop1, but similar alleles of Mot1 and FtsH4. These experiments also ruled out Fop1and suggested that Mot1 and FtsH4 are the best candidate genes for Eps-Am1. We are currently developing TILLING mutants to determine which of these two genes is Eps-Am1.