十字花科黑腐病菌一对假定的双组份信号转导系统基因的功能研究生物化学与分子生物学专业论文.docxVIP

缺失突变体DM3067／3068。测定生长曲线实验结果显示，与野生型菌株相 缺失突变体DM3067／3068。测定生长曲线实验结果显示，与野生型菌株相 比，突变体DM3067、DM3068和DM3067／3068在基本培养基和丰富培养 基中的生长没有变化；致病生化因子检测实验结果显示，与野生型菌株相 比，突变体DM3067、DM3068和DM3067／3068的胞外多糖、胞外蛋白酶、 胞外淀粉酶和胞外纤维素酶和游动性等均没有显著差异；抗逆性检测实验 结果显示，与野生型菌株相比，DM3067、DM3068和DM3067／3068耐受 蛋白质变性剂的能力下降，渗透压抗性和有机溶剂抗性没有变化；在寄主 满身红萝卜的致病性检测实验结果表明，与野生型菌株相比，突变体 DM3068和DM3067／3068的致病力有显著变化；在非寄主辣椒上的过敏反 应实验检测结果表明，与野生型菌株相比，突变体DM3067和DM3068的 过敏反应减弱。DM3067和DM3068的反式互补菌能基本回复表型至野生 型水平，表明XC3068与致病性相关，而XC3067和XC3068与过敏反应和 蛋白质变性剂抗性相关。RT-PCR实验结果表明，XC3067和XC3068位于 同一转录单元，很可能组成一个双组份信号转导系统。RT-PCR实验结果还 表明，XC3067和XC3068在MMX的表达量与在NYGB中的表达量一致， 在MMX条件下中不受hrpG和hrpX调控。 本研究结果显示XC3067和XC3068这对推测的双组份信号转导系统 基因可能与野生型的致病力、过敏反应和蛋白质变性剂抗性相关。并且 XC3067和XC3068位于同一转录单元，不被M^Ⅸ诱导表达，不被hrpG 和hrpX在MMX培养基条件下调控。 关键词：十字花科黑腐病菌双组份信号转导系统致病性过敏反应耐受 性 V 万方数据 IDENTIFICATION IDENTIFICATION OF A PAIR 0F HYPOTHETICAL TWO ·COMPONENT SIGNAL TRANSDUCTION SYSTEM GENES lN XANTHoMoNAS CAMPEsTRIS PN．cAMPESTRIS ABSTRACT Xanthomonas campestris pv．campestris(Xcc)，belonging to the ),-subdivision of the proteobacteria，can infect almost all members of the crucifer family in the worldwide，which is one of the model organisms in studying plant—pathogen interactions．Two—component signal transduction system(TCSs)is one of the important signal transduction systems in bacteria． Typically,this system is comprised of a histidine kinase(HK)that receives the input stimuli and a response regulator(RR)that effects an appropriate change in cellular physiology．Genome analysis showed that Xcc 8004 strain has a total of 1 1 1 two-component signal transduction system genes．There are still many genes functions of two—component signal transduction systems unclear, including XC3067 and XC3068，which consist of a pair of hypothetical two—component signal transduction system genes．Bioinformatics analysis showed that XC3068 located in the genome next to XC3067,has 1 4 bp overlapping with each other,at the 5-end ofXC3067 and the 3’end ofXC3068． They were predicted to be transcribed in