| Summary: | 碩士 === 國立臺灣大學 === 植物病理與微生物學研究所 === 92 === Stimulations of biotic or abiotic factors alter physiological or biochemical reactions of plants to evolve multiple complex defense mechanisms for resistance to adverse stress and pathogen infection. So far, plant defense mechanisms include pre-existed and induced resistance. Induced resistance of plants includes systemic acquired resistance (SAR)、induced systemic resistance (ISR) and hypersensitive response (HR). Botrytis leaf and blossom blight caused by Botrytis elliptica (Berk.) Cooke is an important disease for the bulb and flower productions of Lilium spp. and causes severe losses of yield and value of lilies in Taiwan. For biocontrol of Lilium formosanum Wall., application of rhizobacteria was proposed for practical use. Sixty-two bacterial strains were isolated and purified from L. formosanum rhizosphere soil by dilution plate method and identified according to the fatty acid profiles by MIDI identification system. Bacterial strains promoting the growth of the seedling of Formosa lily, without negative effect, were selected. The greenhouse and field disease control assay showed that the disease severity of Botrytis leaf blight could be decreased effectively by application of bacterial suspension of Bacillus spp. and Pseudomonas spp. in the rhizosphere of lily plants. For cloning of defense-related genes or molecular markers for the induced resistance of L. formosanum, PCR-select cDNA subtraction was implemented to screen out the rhizobacterium-responsive genes. Among 193 clones, twenty-three were differentially expressed as indicated by dot blot hybridization.
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