The present invention concerns a nucleic acid and, thus, the transcribed polypeptide, that induces resistance against sedentary nematodes in plants of the Solanaceae, Chenopodiaceae and/or Brassicaceae families. The nucleic acid comprises a translated region that is at least 60% homologous to the sequence of the HS1.sup.pro-1 gene from Beta procumbens. Methods of making and using a nucleic sequence of the invention are described, implementing recombinant DNA technology. For instance, vectors and plants can be engineered to contain a nucleic acid according to the invention. Furthermore, test kits containing the nucleic acid and/or a vector are provided.