The present invention relates to nucleic acid molecules configured to increase or decrease expression of a nucleic acid molecule that encodes a HrpN-interacting protein; nucleic acid constructs that include these nucleic acid molecules; host cells, transgenic plants, and transgenic plant seeds transformed thereby; and methods of increasing plant growth or imparting disease resistance to plants. Also disclosed are an isolated HIPM nucleic acid molecule and an isolated HIPM protein or polypeptide.