Identification of trasncripts controlled by ploidy and/or diplosporous apomixis in Eragrostis curvula

JUAN P. SELVA; SILVINA PESSINO; MAURO MEIER; DIEGO ZAPPACOSTA; VIVIANA ECHENIQUE

Ciudad de Buenos Aires, Argentina.

Simposio; The 6th International Symposium on the Molecular Breeding of Forage and Turf MBFT 2010; 2010

RedBio

The aim of this work was the identification of genes that are controlled by ploidy and/or by the reproductive mode in the apomictic grass Eragrostis curvula. An analysis of the transcriptome was made by differential display of leaves and flowers of a geneticallyrelated euploid series of plants with different ploidy levels and reproductive modes. With more than 100 primer combinations, 4,242 and 7,622 total markers were generated, rendering 554 and 739 differential bands in flowers and leaves, respectively. From these bands, 11.84 and 6.74% were related to ploidy and 0.71 and 2.17% to the reproductive mode. A small percentage of bands (0.5 and 0.78 %) showed similarity between the tetraploid apomictic and the diploid sexual plants (unexpected pattern). Dendrograms and principal component analysis graphics showed strong similarity between the tetraploid genotypes suggesting that ploidy is more important than tissue type in defining the transcriptome structure. Eighty seven sequences matched successfully with annotated Arabidopsis sequences and were assigned to different metabolic pathways. Thirty nine out of 60 and 14 out of 42 sequences from flowers and leaves showed strong homology to known genes. Genes were in silico mapped onto maize chromosomes, focused on 6L, 8L and 3L since the Tripsacum dactyloides DIP locus was shown to be linked to csu68 marker, located on them. Expression of genes located in the diplo-region might be strongly influenced by ploidy and silenced in the apo genotype. These findings are discussed in order to understand the molecular basis of diplospory and its connection with ploidy.