The present disclosure relates to melon plants that are resistant to the plant disease downy mildew caused by the pathogen Pseudoperonospora cubensis. Specifically, the present disclosure relates to melon plants that are resistant to downy mildew disease including a mutated homoserine kinase gene encoding a mutated homoserine kinase protein. The present disclosure further relates to seeds, tissues, cells, or plant parts of the present melon plants, and to methods for identifying downy mildew resistant melon plants.