Pyrus communis: 'Ercolini' cultivar vs. 'Rocha' cultivar. Pyrus communis

Transcriptional profiling of pear tree comparing a resistant/tolerant cultivar with a susceptible cultivar to the Stemphylium vesicarium fungus Rocha' pear is an economically important portuguese Pyrus communis L. cultivar very susceptible to the Stemphylium vesicarium pathogenic fungus, the brown spot agent, causing huge decrease on fruit quality and yield production. Field control of brown spot disease is based in systemic application of antifungal chemicals with high economic costs and dramatic consequences to public health and environmental pollution. Plant-pathogen interactions involve a series of events encompassing constitutive and induced plant defence responses whose dissection has been a research target for control many crop diseases. The biosynthesis of cell wall polymers and antifungal compounds appear to be an efficient physical and chemical barrier to infection.To understand the molecular responses behind defence mechanisms of resistant/tolerant and susceptible cultivars of Pyrus communis L. to the S. vesicarium fungus, cDNA microarray technology was used to identify the genes differentially expressed along a time course leaf inoculation between 'Rocha' pear cultivar (a high susceptible cultivar) and 'Ercolini' pear cultivar (a resistant/tolerant pear cultivar). This study aims to contribute with information on the molecular mechanisms involved in host-pathogen interactions responsible for pear tree brown spot disease and resistance to Stemphylium vesicarium. Overall design: Experimental condition: 'Ercolini' vs 'Rocha' (each experiment including 5 plants from each cultivar). 3 time-points: water-inoculation (T0h), 6 hours after inoculation with S. vesicarium (T6h) and 24 hours after inoculation with S. vesicarium. Biological replicates: 3 in each time-point. One replicate per array.