Project description:Five years old Ulmus minor plants from three different genotypes, two tolerant and one sensitive to Dutch Elm disease, were inoculated with an aggressive local strain of Ophiostoma novo-ulmi (Z-BU1) while the other half were inoculated with sterile and distilled water as control treatment. following the procedure described by Solla et al. (2005). A healthy 3-year-old branch located around 2 meters tall, from both inoculated and control plants, were collected at 1, 3, 7, 14 and 21 days after inoculation. The stem from the branch was individualized and RNA isolated to hybridize two colors microarrays.