Virulence variation of Xanthomonas oryzae pv. oryzae toward rice Taichung Native-1

• Main Authors: Chun-Yu Feng, 馮鈞育
• Other Authors: Wen-Ling Deng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/78176393158798409916

碩士 === 國立中興大學 === 植物病理學系所 === 94 === Bacterial blight of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo) , is one of the important disease in many rice-growing areas. Several Xoo strains isolated from Taiwan were inoculated in rice cultivar Taichung Native-1 (TN-1), and the lesion length was measured 16 days after inoculation. According to the lesion length, the Xoo strains used in this study were categorized into severely, moderately and weakly virulent strains with representatives Xoo28 (severely virulent strains) and Xoo20 (weakly virulent strains). To understand the difference in virulence toward rice cultivar TN-1 among different Xoo strains might be due to the difference in their genome organization. Utilizing genome subtractive hybridization and Southern hybridization, a DNA fragment was identified that was present in the highly virulent strain Xoo28 and absent in the weakly virulent strain Xoo20. To facilitate DNA analysis, a BAC clone, pCHUB79, was isolated from Xoo28 genomic library and found to contain the differential 3.5 kb DNA fragment. Sequence analysis using FramePlot 3.0beta, Vector NT1 and Blast analysis showed the differential DNA fragment is not present in the two sequenced Xoo genomes (Xoo KACC10331, Xoo MAFF311018), and only some Xoo strains isolated from Taiwan contain it, suggesting the differential DNA fragment might be introduced into the Xoo strains through horizontal gene transfer.