The present invention provides a method for improving transformationefficiency of a plant. The method according to the present inventioncomprises the use of a nucleic acid encoding the amino acid sequence set forthin SEQ ID NO: 2 or 4, or a nucleic acid encoding a polypeptide comprising anamino acid sequence having at least 85% identity with the amino acid sequenceset forth in SEQ ID NO: 2 or 4, and having a function of improvingtransformationefficiency of a plant.