【作者】 张国庆；

【导师】 谢关林；

【作者基本信息】 浙江大学 ， 植物保护， 2012， 硕士

【摘要】 近年来,在国内不少地方相继爆发了水稻细菌性褐条病。为明确该病原,从而为有效防控提供理论基础,本文在实验室前期的研究基础上,对采自浙江富阳市的水稻细菌性褐条病样本进行分离,利用电镜、Biolog、FAMEs、16S rDNA Phylogeny等技术,从生理生化到分子生物学水平上对病原进行了系统鉴定,病原细菌为Acidovorax avenae subsp. avenae.由于该病菌与我国另一种重要的瓜果病害-西瓜果斑病菌(Acidovorax avenae subsp. citrulli)亲缘关系非常近,因此在国内外首次对该病菌的全基因组进行了测序。根据Reference序列和SOAPdenovo、GapCloser等软件对测序结果进行了拼接、组装和注释,对contigs内部残缺的序列也进行了补充,完成了该病原菌基因组的精细图,并对该基因组的特征进行了初步分析。最后还尝试利用Tn-5转座子系统构建了该病原细菌的突变体库,筛选到了两株致病力减弱的突变体。我们利用染色体步移技术对这两株突变体进行了转座子定位,明确了插入位点及被破坏的基因分别为fadD和pliO.更多还原

【Abstract】 Rice brown stripe disease broke out in some rice growing areas in China recently. The pathogen of the disease was isolated and identified with systematic methods to determine the causal organism for providing the basis of effective management. The pathogen was identified as Acidovorax avenae subsp. avenae after pathogenicity, TEM, Biolog, FAMEs and16S rDNA analysis.A. avenae subsp. avenae is highly homogeneous with another important pathogen A. avenae subsp. citrulli, the causal agent of bacterial fruit blotch of melon and no genomic information was recorded in the world. Therefore, the whole genome of A. avenae subsp. avenae was sequenced based on the reference sequences and quality filtered reads were assembled by SOAPdenovo and GapCloser softwares. The genome gaps were closed by subsequent PCR and re-sequencing and the sequences were also automatically identified using GenDB annotation engine. The features of the whole genome were preliminarily analysed.Finally, the random mutant library was established using Tn-5transposon system and two mutants with weak-pathogenicity were screened by pathogenicity test. The location where the Tn-5transposon insert to were definited using the genome walking kit and the results indicated that the genes destroyed were fadD and pliO.更多还原