A comparative analysis of the gramineae genomic sequences syntenic to the apospory-controlling region

STEIN JULIANA; SPOTO NICOLÁS; ORTIZ JUAN PABLO; PODIO MARICEL

Zavalla, Rosario

Seminario; V Argentine Seminars on Apomixis Research; 2018

Apomixis is an asexualmode of reproduction by seeds associated with polyploidy. It is anadvantageous trait for agriculture because it guarantees themaintenance of heterosis. P.notatumforms a multiploid species with diploid sexual self-sterile andpolyploid aposporous apomictic self-fertile cytotypes. Apomixis inthe tetraploid race is controlled by a single chromosomal region(ACR) that showed segregation distortion, lack of recombination andsynteny with segments of rice chromosomes 2 and 12. Apospory (one ofthe apomixis components) was observed in diploid genotypes, althoughwith low expressivity. The objectives of this work were to localizethe homologous region/s of the ACR in the diploid genome and identifyputative candidates. A draft assembly of the diploid genome,generated by a combination of Illumina® and Oxford Nanopore® reads,was used as a reference. Twenty ACR-specific sequences from thetetraploid genotype Q4117 were blasted (BLASTN, score> 250, Evaluee <1e-50)over the reference. Out of the 64,166 scaffolds available (averagelength 5,674 bp), 84 carried ACR-specific sequences. Scaffoldsmapping against rice confirmed the syntenic relationships. ORFssearching within scaffolds detected coding sequences associated withdevelopment and reproduction. Plotting the selected scaffolds againstthe ACR-specific sequences showed that the structure of the ACR ispartially conserved in the diploid genome. These results suggestedthat the ACR could be originated during speciation and that apomixisdeterminant/s can be present at the diploid level.p { margin-bottom: 0.2cm; direction: ltr; line-height: 115%; text-align: justify; background: transparent none repeat scroll 0% 0%; }p.western { font-family: "Linux Libertine:onum=1", serif; }p.cjk { font-family: "Droid Sans Fallback", "Times New R"; }p.ctl { font-family: "Arial"; font-size: 18pt; }