PROBLEM TO BE SOLVED: To obtain a novel polypeptide which contains a specific amino acid sequence, exhibits avidity to a promosaic virus envelope protein, originates from Hordeum vulgare L. var. hexastichon, participates in the infection with a plant virus and is capable of giving a virus resistance to plants.
SOLUTION: This polypeptide is a novel polypeptide comprising a polypeptide containing the amino acid sequence represented by the amino acid numbers of 1 to 352 represented by the formula or a polypeptide which is obtained by deleting, substituting or adding a part of polypeptide comprising the amino acid sequence represented by the formula and exhibits avidity to a promosaic virus envelop protein. Since a gene originating from Hordeum vulgare L. var. hexastichon codes for a protein which exhibits avidity to the promosaic virus envelop protein and is essential to the multiplication of a plant virus, it is possible to form plants having resistance to the virus by the modification of this gene. This polypeptide is obtained by screening out a complementary DNA library of Hordeum vulgare L. var. hexastichon by means of using two hybrid systems of yeast and transducing the resultant gene into plants to express it.