Identification of a Genomic Region Linked to Apomixis in Eragrostis Curvula.

CARBALLO JOSE; GALLARDO JIMENA; GALLO, C.A.; SELVA JUAN PABLO; GARBUS INGRID; ZAPPACOSTA DIEGO; ALBERTINI EMIDIO; CACCAMO MARIO; ECHENIQUE VIVIANA

Workshop; VII Ciclo de Seminarios sobre avances en la Caracterización Genética y Molecular de la APOMIXIS; 2020

Eragrostis curvula is a forage grass with n = 10 and ploidy levels ranging from 2× to8×. This grass has become a model for the study of diplosporous apomixis, an asexualreproduction by seeds in which the progeny is genetically identical to the mother plant.To identify the genomic regions and the genes involved in apomixis, the genome of thediploid sexual cultivar Victoria was sequenced using a combination of approaches (Pac-Bio, Chicago and Hi-C) and contrasted against the region identified by high density mapping.The final assembly render an N50 of ~43 Mb and 1143 contigs being completely assembledthe seven longest full chromosomes according to the synteny analyses. The annotationidentified 56,469 genes and 28.7% of repetitive elements. On the other hand, ahigh saturated linkage map at tetraploid level was constructed using both traditional(AFLP and SSR) and high-throughput molecular markers (GBS-SNP) and a locus controllingdiplospory and putative regulatory regions affecting the expressivity of the trait wereidentified. The four markers linked to apomixis in the E. curvula linkage map were alignedto Victoria, identifying a 10 Mb region. Furthermore, using a transcriptomic approach,genes up and downregulated in the apomictic genotypes were identified, including genesthat could be repressing sexuality or promoting apomixis. The identification of the regionlinked to apomixis, its expression and regulation could allow to better understand somefeatures of this interesting trait and it paves the way to sequence and assemble the completeregion in the more complex polyploid genotypes.