Histone methyltransferase (By similarity). Involved in stamen development. L-lysyl-[histone] + S-adenosyl-L-methionine = H(+) + N(6)-methyl-L-lysyl-[histone] + S-adenosyl-L-homocysteine Interacts with AMS/bHLH21 by its SET domain and PHD finger. Associated to the euchromatin. Expressed in roots, flowers and buds, the anther and in stamen filaments. First observed at low levels in the vasculature and around hydathodes of developing leaves. In flowers, restricted to anthers tapetum at a post-meiosis stage, to filaments, and to microspores during their development. Disappears as pollen matures. In developing roots, expressed throughout the lower part, in the cap, in the epidermis and in non-epidermal tissue in the division and elongation zone. Also detected in cells lining lateral root formation. Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. SET2 subfamily.