[The mechanism of histone lysine methylation of plant involved in gene expression and regulation].

Histone modification is one important sort of the epigenetic modifications, including acetylation, formylation, methylation, phosphorylation, ubiquitination and SUMOylation. By forming a complicated network, these modifications control the expression of genes. Histone methylation occurs mainly on the lysine residues, and plays a key role during flowering and stress response of plants, through changing the methylation status of lysine residues and the ratio of methylation. Triple-methylation of H3K4 promotes FLC expression but triple-methylation of H3K27 inhibits its expression. H3K4me3 activates the expression of PtdIns5P gene to initiate lipid synthesis signal pathway in response to drought stress. On the contrary, the low levels of H3K27me3 induce the expression of COR15A and ATGOLS3, which encode for low temperature protective proteins of chloroplast (Cor15am) and Galactional Synthase (GOLS), in order to resist cold stress. In this review, we summarize the molecular mechanisms of histone lysine methylation involved in DNA methylation, plant flowering and stress response.