Identification of histone methylation modifiers and their expression patterns during somatic embryogenesis in Hevea brasiliensis.

Histone methylation plays a crucial role in various biological processes, from heterochromatin formation to transcriptional regulation. Currently, no information is available regarding histone methylation modifiers in the important rubber-producing plant Hevea brasiliensis. Here, we identified 47 histone methyltransferase (HMT) genes and 25 histone demethylase (HDM) genes as possible members of the histone methylation modifiers in the rubber tree genome. According to the structural features of HMT and HDM, the HbHMTs were classified into two groups (HbPRMs and HbSDGs), the HbHDMs have two groups (HbLSDs and HbJMJs). Expression patterns were analyzed in five different tissues and at different phases of somatic embryogenesis. HbSDG10, 21, 25, 33, HbJMJ2, 18, 20 were with high expression at different phases of somatic embryogenesis. HbSDG10,14, 20, 21, 33 and HbPRMT4 were expressed highly in anther, HbSDG14, 20, 21, 22, 23, 33, 35 and HbPRMT1 HbJMJ7 and HbLSD1, 2, 3, 4 showed high expression levels in callus. HbSDG1, 7, 10, 13, 14, 18, 19, 21, 22, 23, 35, HbPRMT1, 8, HbJMJ5, 7, 11, 16, 20 and HbLSD2, 3, 4 were expressed highly in somatic embryo. HbSDG10, 21, 25, 33, HbLSD2, 3 were expressed highly in bud of regenerated plant. The analyses reveal that HbHMTs and HbHDMs exhibit different expression patterns at different phases during somatic embryogenesis, implying that some HbHMTs and HbHDMs play important roles during somatic embryogenesis. This study provide fundamental information for further studies on histone methylation in Hevea brasiliensis.