Abstract Detail

Development and Structure

Povilus, Rebecca [1], Gehring, Mary [2].

DNA methylation and genetic imprinting in water lily (Nymphaea) seeds: implications for endosperm and seed evolution.

Endosperm is the product of a second fertilization event that occurs at the inception of flowering plant seeds, and is an important mediator of developmental and nutritional dynamics between an embryo and its mother. The biparental nature of endosperm is a key feature of this seed component, as the ratio of maternal and paternal genomes has been widely shown to impact endosperm development - and seed development as a whole. This parental genome dosage sensitivity has been tied to epigenetic modifications (such as DNA methylation) and imprinted gene expression (when allele expression depends on which parent it is inherited from). The mechanistic basis for parental genome dosage sensitivity has only been examined in systems with triploid endosperm (2:1 maternal:paternal genome ratio), although endosperm ploidy and parental genome dosage show remarkable variation across flowering plants. In order to provide a new perspective on the evolution of endosperm parental genome dosage sensitivity, we examined genetic/epigenetic aspects of endosperm development in Nymphaea - which is part of a lineage that is sister to nearly all other flowering plants. Furthermore, water lily endosperm is diploid (1:1 maternal:paternal genome ratio) and yet has been previously shown to exhibit parental genome dosage sensitivity. We find some water lily-specific patterns in endosperm DNA methylation, while genome-wide DNA hypomethylation appears to be a deeply conserved endosperm trait. We also find a set of genes that are genetically imprinted in water lily endosperm, including transcription factors and terpene synthases. Together, our results indicate that epigenetic modification and imprinted gene expression, while deeply conserved, have likely been evolving in concert with endosperm ploidy and function. Funding/support from NSF ISO-1812116 & DEB-1500963.

1 - Whitehead Institute, 455 Main St, Cambridge, MA, 02142, US
2 - Whitehead Institute & MIT Biology, 455 Main St, Cambridge, MA, 021142, USA

Keywords:
endosperm
seed development
genetic imprinting
epigenetic modification
Evo-Devo.

Presentation Type: Oral Paper
Number: DS5004
Abstract ID:576
Candidate for Awards:None