Global analysis of the genome, transcriptome and epigenome in the diplosporous grass Eragrostis curvula (Schrad.) Nees.

SELVA, JP; CERVIGNI, G; OCHOGAVÍA, A; ZAPPACOSTA, D; MEIER, M; PESSINO, S; ECHENIQUE, V.

Brasilia, Brasil

Congreso; XXth International Congress on Sexual Plant Reproduction; 2008

EMBRAPA

ORAL  CONTRIBUTION Global  analys¡s  of the genome,  transcriptome  and epigenome  in the diplosporous  grass Eragrostis curvula (Schrad.) Nees Selva  JP  1,  Cervigni G  1,  Ochogavía A2,  Zappacosta  Dl, Meier Ml, Pessino 52 and V. Echeniquel lDepartamento  de  Agronomía,  Universidad  Nacional  del  Sur,  CERZOS  CONICET,  San Andrés  800,  Bahía  Blanca,  Argentina.  2Laboratorio  Central  de  Investigaciones,  Facultad de  Ciencias  Agrarias  de  la Universidad  Nacional  de Rosario,  Parque  Villarino,  Zavalla, Santa  Fe,  Argentina.  Email:  echeniq@criba,edu.ar The  Eragrostis  curvula complex have a basic chromosome number of x :  10, and include  a cytotype series  with different  ploidy  levels  (from 2x to 8x) and reproductive  modes.  The most valuable  cultivars  as forage are  tetraploid  and apomictic.  This mode  of reproduction  is strongly  related to ploidy. The aim of this work was to identify genetic, epigenetic  and transcriptional  changes  associated  to the reproduct¡ve  mode in leaves  and panicles  of an euploid  series  obtained  after a tetraploid-dihaploidization procedure followed  by  chromosome  re-doubling with  colchicine. Considerable  levels of genome polymorphisms  were detected between lines,  showing  markers  (31  .45o/o  of 1008 RAPD  and  AFLP)  with a revertant behavior  (9O  o/o  of the polymorphic  bands)  following  the changes  of ploidy. This suggests  that genome  alterations  were specific  and conferred  genetic structures characteristic of a given ploidy level. Polymorphic revertant sequences  involved  mostly non-coding  regions,  although  some of them displayed  sequence  homology  to known genes.  Two per cent of the changes were related  to the reprodúelive  mode (apo  vs sex). Changes  in cytosine methylation  patterns  were also  observed,  affecting  mainly  coding  regions (27 o/o  of the 364 markers  showed epigenetic  variation).  A comparative expression  analysis  based on ESTs showed that from 8,884 unigenes (inflorescence-derived  libraries),  112 (1.260/ol  had significant  differential expression  in individuals  with different ploidy level and/or reproductive mode. Independent  comparisons  between  plants  with different  reproductive mode (same ploidy)  or different ploidy level (same reproductive  mode) allowed  the identification  of genes  modulated  in response  to diplosporous development  or polyploidization,  respectively.  A group of 50 genes  were