A High-Density Linkage Map of the Forage Grass Eragrostis curvula and Localization of the Diplospory Locus

ZAPPACOSTA D; GALLARDO J; CARBALLO J; MEIER M; RODRIGO JM; GALLO CA; SELVA JP; STEIN J,; ORTIZ JP; ALBERTINI E; ECHENIQUE V

Frontiers in Plant Science

Frontiers Media

Año: 2019 vol. 10

1664-462X

Eragrostis curvula(Schrad.) Nees (weeping lovegrass) is an apomictic species native toSouthern Africa that is used as forage grass in semiarid regions of Argentina. Apomixisis a mechanism for clonal propagation through seeds that involves the avoidance ofmeiosis to generate an unreduced embryo sac (apomeiosis), parthenogenesis, andviable endosperm formation in a fertilization-dependent or -independent manner. Here,we constructed the first saturated linkage map of tetraploidE. curvulausing bothtraditional (AFLP and SSR) and high-throughput molecular markers (GBS-SNP) andidentified the locus controlling diplospory. We also identified putative regulatory regionsaffecting the expressivity of this trait and syntenic relationships with genomes of othergrass species. We obtained a tetraploid mapping population from a cross between afull sexual genotype (OTA-S) with a facultative apomictic individual of cv. Don Walter.Phenotypic characterization of F1hybrids by cytoembryological analysis yielded a 1:1ratio of apomictic vs. sexual plants (34:27,X2= 0.37), which agrees with the modelof inheritance of a single dominant genetic factor. The final number of markers was1,114 for OTA-S and 2,019 for Don Walter. These markers were distributed into 40linkage groups per parental genotype, which is consistent with the number ofE. curvulachromosomes (containing 2 to 123 markers per linkage group). The total length of theOTA-S map was 1,335 cM, with an average marker density of 1.22 cM per marker.