The role of nucleic acid methyltransferases in the switch from sexuality to apomixis in grasses

OLIVIER LEBLANC; LORENA SIENA; JUAN PABLO SELVA; JUAN PABLO ORTIZ; VIVIANA ECHENIQUE

Rosario

Congreso; ALAG 2012; 2012

Apomixis in flowering plants covers a wide range of behaviors leading to the formation of maternal embryos within seeds. Our current view on apomictic development postulates that apomixes emerges from sexuality through alterations in the regulation of the developmental programs governing sexual reproduction. Although apomixes is genetically determined, the nature of the loci underlying the trait remains largely unknown. Recently, works in both sexual and apomictic species have pointed out a role for nucleic acid methyltransferases in the shift from sexuality to apomixis. First, functional analyses in maize revealed that knock outs in DNA methyltransferases dmt102 and dmt103 cause reproductive phenotypes reminiscent of apomixis. Interestingly, these methytransferases are deregulated in Tripsacum, a wild apomictic relative of maize. Second, RNA profiling and genetic mapping in Paspalum showed that deregulation of loci encoding for t- and mRNA methyltransferases is associated with apospory. We are currently exploring whether deregulation of nucleic acid methylation pathways could determine the emergence of apomixis in sexual species. We will report progress towards the isolation and expression patterns of several candidate genes encoding DNA and RNA methyltransferases in three apomictic systems: Tripsacum dactyloides, Paspalum notatum and Eragrostis curvula. This work will further serve as a foundation for the functional characterisation of the best candidates.