Evolution and function of epigenetic processes in the endosperm.

Area of Science:

• Plant reproductive biology
• Epigenetics
• Evolutionary genomics

Background:

• The endosperm is a vital, transient tissue supporting embryo development.
• Epigenetic mechanisms in the endosperm are hypothesized to control transposable elements (TEs) in the embryo.
• DNA demethylation in the central cell may generate small RNAs that induce DNA methylation in the egg and embryo.

Purpose of the Study:

• To investigate the role of Polycomb Repressive Complex 2 (PRC2) in the endosperm.
• To explore the connection between endosperm PRC2, TE silencing, and sexual conflict.
• To discuss the evolutionary implications of endosperm PRC2 for genome expansion.

Main Methods:

• Analysis of epigenetic processes within the endosperm.
• Investigating the targeting of PRC2 to DNA hypomethylated regions.
• Assessing the impact of maternal genome dosage on PRC2 function.

Main Results:

• PRC2 is targeted to hypomethylated DNA regions in the endosperm.
• Endosperm PRC2 function can be compensated by increased maternal genome dosage.
• This suggests a role for endosperm PRC2 in mitigating sexual conflict.

Conclusions:

• Endosperm PRC2 likely evolved to enforce TE silencing, coupled with the development of a sexual endosperm.
• This mechanism may have played a role in resolving sexual conflict and facilitating genome expansion.