Project description: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. 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.
Project description:Bud mutation (bud sport) is mutation occurred in one branch in a tree and the mutant branch shows different phenotype from normal branches. Because bud mutation occurs in a part of plant body, genomic backgrounds of mutant branch and normal branches are the same, except some mutations. Therefore bud mutants are ideal material to identify key genes for important traits of crops. We studied ‘Giant Laf’, a bud mutant setting large fruit, which generated spontaneously in European pear ‘La France’ tree. In ‘Giant Laf’, increase of cell size and DNA reduplication occurred specifically in fruit flesh. The DNA reduplication in ‘Giant Laf’ was observed at 1 week before full bloom stage. This suggested that DNA reduplication observed in ‘Giant Laf’ fruit is not endoreduplication, but endomitosis or nuclear fusion. To identify genes expressed differentially between in ‘Giant Laf’ and in ‘La France’, microarray analysis was performed with RNA from receptacle (fruit flesh) at 1 week before full bloom stage. To isolate the receptacle, laser microdissection was applied. Genes encoding proteins localized in nucleus and cytoskeleton were up-regulated in ‘Giant Laf’. Among these genes, we found several genes which shared homology with previously described DNA reduplication related genes. These are candidates of responsible gene of ‘Giant Laf’ mutation.
Project description: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.
Project description:Bud mutation (bud sport) is mutation occurred in one branch in a tree and the mutant branch shows different phenotype from normal branches. Because bud mutation occurs in a part of plant body, genomic backgrounds of mutant branch and normal branches are the same, except some mutations. Therefore bud mutants are ideal material to identify key genes for important traits of crops. We studied M-bM-^@M-^XGiant LafM-bM-^@M-^Y, a bud mutant setting large fruit, which generated spontaneously in European pear M-bM-^@M-^XLa FranceM-bM-^@M-^Y tree. In M-bM-^@M-^XGiant LafM-bM-^@M-^Y, increase of cell size and DNA reduplication occurred specifically in fruit flesh. The DNA reduplication in M-bM-^@M-^XGiant LafM-bM-^@M-^Y was observed at 1 week before full bloom stage. This suggested that DNA reduplication observed in M-bM-^@M-^XGiant LafM-bM-^@M-^Y fruit is not endoreduplication, but endomitosis or nuclear fusion. To identify genes expressed differentially between in M-bM-^@M-^XGiant LafM-bM-^@M-^Y and in M-bM-^@M-^XLa FranceM-bM-^@M-^Y, microarray analysis was performed with RNA from receptacle (fruit flesh) at 1 week before full bloom stage. To isolate the receptacle, laser microdissection was applied. Genes encoding proteins localized in nucleus and cytoskeleton were up-regulated in M-bM-^@M-^XGiant LafM-bM-^@M-^Y. Among these genes, we found several genes which shared homology with previously described DNA reduplication related genes. These are candidates of responsible gene of M-bM-^@M-^XGiant LafM-bM-^@M-^Y mutation. The gene expression profiles between European pear (Pyrus communis) M-bM-^@M-^XLa FranceM-bM-^@M-^Y and its bud mutant M-bM-^@M-^XGiant LafM-bM-^@M-^Y were compared. RNA was extracted from receptacle which was isolated from flower bud at 1 week before full bloom stage by using laser microdissection. Three biological replications were analyzed.