PROBLEM TO BE SOLVED: To obtain a new DNA, having a base sequence capable of coding a coat protein of a patchouli mild mosaic virus (PaMMV) and useful for breeding, etc., of a plant having the resistance to infection with the PaMMV by transduction thereof into a plant cell. SOLUTION: This new DNA has a base sequence capable of coding a polypeptide of a coat protein of a patchouli mild mosaic virus (PaMMV) represented by the formula or a polypeptide in which a part of amino acids thereof are substituted, inserted, added or removed. The DNA is useful for breeding, etc., of a plant having the resistance to infection with the PaMMV by transduction into the plant. The DNA is obtained by inoculating the PaMMV into a patchouli, growing the PaMMV, harvesting an infected leaf remarkable in disease symptoms, separating the virus therefrom according to a conventional method, purifying the virus, extracting an RNA thereof, synthesizing a cDNA using the RNA as a template, cloning the synthesized cDNA and selecting a clone containing the cDNA capable of coding the coat protein.
