Imprinting, methylation, and expression characterization of the maize ETHYLENE-INSENSITIVE 2-like gene

The endosperm plays essential roles in embryogenesis and seed germination and provides abundant resources for human food and industrial products. Identification of genes regulating the development of the endosperm and elucidation of their functions is of great importance for maize genetics and breeding. This study showed that the gene-specific imprinted gene, ETHYLENE-INSENSITIVE 2-like (EIN2-like), is maternally expressed in both endosperm and embryo. The maternally expressed pattern was maintained throughout later seed developmental stages. Bisulfite sequencing using DNA obtained from hybrid endosperm tissues showed that the upstream regions of the alleles of EIN2-like were highly methylated at symmetrical sites (CG and CHG). A differentially methylated region in the upstream part of the maternal allele of EIN2-like was identified and found to be hypomethylated. Expression analysis showed that EIN2-like was highly expressed in the maize endosperm as well as at different stages of cell differentiation (8–12days after pollination) in the hybrid endosperm. These results suggest that the maternally expressed gene EIN2-like may play crucial roles in the regulation of seed development.