Described herein are inventions in the field of genetic engineering of plants, including isolated nucleic acid molecules encoding digalactosyl diacylglycerol synthase 1-like (DGD1-like) polypeptides to improve agronomic, horticultural and quality traits. This invention relates generally to nucleic acid sequences encoding proteins that are related to the presence of seed storage compounds in plants. More specifically, the present invention relates to DGD1-like nucleic acid sequences encoding sugar and lipid metabolism regulator proteins and the use of these sequences in transgenic plants. The invention further relates to methods of applying these novel plant polypeptides to the identification and stimulation of plant growth and/or to the increase of yield and/or composition of seed storage compounds.