Résumé
The mantled variation of oil palm (Elaeis guineensis) involves a significant deficit in genome-wide methylation as well as the mis-expression of a variety of genes affecting both the in vitro-propagated material from which the palms originate and the adult regenerants (for a review see [1]). This reversible floral phenotype is morphologically similar to B-class MADS-box mutants: indeed, the abnormal flower displays an homeotic conversion of male floral organs into female ones [2]. In order to investigate the role of epigenetic processes in the transcriptional regulation of EgDEF1, the ortholog of APETALA3/DEFICIENS in the oil palm genome, we have studied the DNA methylation pattern of this gene concomitantly with its transcript production in the developing inflorescence. The exploration of the genomic region surrounding the gene led to the isolation of several retroelements which were also examined. Although our results do not point to a direct implication of DNA methylation in the regulation of the EgDEF1 gene, they raise exciting new questions about the possible mechanisms underlying the variant phenotype. (Texte intégral)