Scientists from the Cold Spring Harbor Laboratory in New York have completed a research that uncovered a mechanism by which plants inherit epigenetic modifications. The study found that plants' genome reprogramming through epigenetic mechanisms is guided by small RNAs and is passed on to the next generation. The said study further implies that epigenetic inheritance - the inheritance by offspring of chemical "tags" present in parental DNA that modify the expression of genes - is much more widespread in plants than in animals.
examine the set of modifications on the DNA in plant pollen grains,
scientists decided to look at the particular set of chemical marks
called methyl groups. When they separated out pollen grains in different
stages of development, they found distinct patterns of the attachment
of methyl groups to DNA. They also noticed the corresponding
accumulation of small RNAs, including two classes of so-called
short-interfering RNAs (siRNAs) – tiny RNA molecules, 21 or 24
nucleotides in length -- involved in silencing gene expression. These
small siRNAs act as guides to where methylation will occur, silencing gene expression.
See the original article at http://www.cshl.edu/Article-Martienssen/scientists-uncover-mechanism-by-which-plants-inherit-epigenetic-modifications.