Functional Study Of Rice H3K36Methyltransferase SDG725in Rice Growth And Development

Histone H3K36lysine methylation plays an essential role in epigenetic regulation of gene expression in eukaryotes.Enzymes responsible for H3K36methylation have been reported in Arabidopsis but absent in rice. Here we report a rice H3K36-specific methyltransferase SDG725which down-regulation mutants display multiple defects, including dwarfism, shortened internodes, late flowering, erect leaves and small seeds. The dwarf and erect phenotypes have been usually described in brassinosteroid (BR)-knockdown mutants. We examine the expression level of rice flowering genes and brassinosteroid-related genes and found that these related genes are all down-regulated in sdg725background. To further detect the function of SDG725in vivo, we did Chromatin immuno-precipitation (ChIP) in WT and sdg725, respectively. The H3K36m2/m3levels were down-regulated in some brassinosteroid pathway and the flowering related genes. Moreover, the SDG725protein was able to directly bind at these target genes.Taken together, our data indicate that the SDG725-mediated H3K36methylation modulates BR-related and rice flowering related genes expression, playing an important role in rice plant growth and development.