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

JUAN PABLO SELVA; SILVINA PESSINO; MAURO MEIER; GERARDO CERVIGNI; DIEGO ZAPPACOSTA; VIVIANA ECHENIQUE

PLANT PHYSIOLOGY.

Año: 2009

0032-0889

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 genetically- related 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.