十字花科黑腐病菌中一类与趋化性相关的感受蛋白基因的研究

发布时间：2018-06-12 11:32

本文选题：十字花科黑腐病菌 + 趋化性　；参考：《广西大学》2015年硕士论文

【摘要】：十字花科黑腐病菌(Xanthomonas campestris pv.campestris,Xcc)是引起十字花科植物发生黑腐病的病原菌,该菌同时也是研究微生物与寄主植物相互作用分子机理的重要模式菌,研究该菌的致病机理对于减少农业经济损失具有重大的意义。目前,细菌的趋化性在病原学方面的意义已经被公认。寄主体内含有各种化学物质,因此病原菌的趋利避害显得尤为重要。根据Xcc8004基因组的注释,XC_2307, XC_0286, XC_1074, XC_2313, XC 2504、XC 2304、XC 2316、XC 2320、XC 0336、XC 2306、XC 2136、 XC 1801、XC 1937、XC 2315、XC 2314、XC 0843、XC 1412、XC 1414、 XC_2308、XC_1413、XC_2223、XC_2309、XC+2311、XC_0638这24个基因的编码产物是趋化蛋白。为了评估这24个基因的功能,本研究利用pKl8mobSacB对这些基因分别进行突变,构建了24个基因的缺失突变体,并对这些突变体进行表型分析。植株试验发现,与野生型菌株相比较,突变体DM2311基本丧失致病性,DM2223、DM2304、DM1937这三个突变体的致病性降低了大约30%,它们的互补菌能恢复野生型的致病力水平。表明XC_2311、XC_2223、XC_2304、XC 1937与病原菌的致病性相关。对突变体的生长分析发现,DM2311、DM2223、DM2304以及DM1937这四个突变体在MMX培养基的生长缓慢,它们的互补菌的生长与野生型基本一致,表明XC_2311、XC_2223、XC_2304以及XC_1937与菌体繁殖相关；运动性检测发现,DM2311、DM2223、DM2304以及DM1937在含0.3%以及0.6%琼脂糖游动板的游动性降低,它们的互补菌的游动性与野生型基本一致,表明XC_2311、XC_2223、XC_2304以及XC 1937与菌株的游动性相关；运用毛细管法检测了Xcc8004对30种化学物质(麦芽糖、葡萄糖、果糖、木糖、乳糖、蔗糖、核糖、阿拉伯糖、甘露醇、酪氨酸、精氨酸、丙氨酸、亮氨酸、丝氨酸、赖氨酸、色氨酸、苏氨酸、组氨酸、缬氨酸、谷氨酰胺、谷氨酸、天冬氨酸、半胱氨酸、脯氨酸、苯丙氨酸、异亮氨酸、氯化镁、氯化钙、氯化铵、柠檬酸)的趋化性,结果发现野生型菌株对18种物质(蔗糖、麦芽糖、乳糖、核糖、果糖、半乳糖、木糖、葡萄糖、半胱氨酸、脯氨酸、苯丙氨酸、谷氨酰胺、丝氨酸、异亮氨酸、精氨酸、亮氨酸、氯化钙、氯化镁)具有比较明显的趋化性,为了分析这24个基因如何影响菌株的趋化性,我们分析了这些突变体对这18种物质的趋化性。趋化性检测发现,Xcc8004主要对一些参与细胞生命活动的糖类、氨基酸、以及无机盐离子具有明显的趋化性。这些突变体的HR、生物膜、重金属抗逆性、胞外酶、EPS产量与野生型菌株相比并没有明显的差异。
[Abstract]:Xanthomonas campestris pv. Campestris Xcc. is the pathogen causing black rot in cruciferous plants. It is also an important model bacterium for studying the molecular mechanism of interaction between microorganisms and host plants. It is of great significance to study the pathogenic mechanism of this bacterium to reduce the agricultural economic loss. At present, the chemotaxis of bacteria in the etiological significance has been recognized. The host contains all kinds of chemical substances, so it is very important for pathogenic bacteria to take advantage and avoid harm. XC2307, XC0286, XC1074, XC2313, XC2504 XC23304, XC23304 XC2320, XC2306XC2136, XC1801XC1937XC2315XC23141412XC1414, XC2308131313, XC23309XC2311XC0638, the encodings of the 24 genes are chemotaxis proteins. In order to evaluate the function of these 24 genes, we used pKl8mob SacB to mutate these genes, and constructed the deletion mutants of 24 genes, and analyzed the phenotypes of these mutants. Plant experiments showed that the pathogenicity of the mutant DM2311 was reduced by about 30% compared with that of wild type strain DM2311. The pathogenicity of the three mutants, DM2223, DM2304 and DM1937, was reduced by about 30 percent, and their complementary bacteria could restore the pathogenicity of wild type. The results showed that the pathogenicity of the pathogenic bacteria was related to XC2311XC22323 XC1937, which was related to the pathogenicity of the pathogenic bacteria. The growth analysis of the mutant showed that the four mutants DM2311, DM2223, DM2304 and DM1937 grew slowly in MMX medium, and the growth of their complementary bacteria was basically the same as that of wild type, which indicated that XC2311, XC2223 XC2304 and XC1937 were related to cell propagation. The results of exercise test showed that DM2311, DM2223, DM2304 and DM1937 decreased the mobility of DM2304 and DM1937 in 0.3% and 0.6% agarose swimming plates, and the swimming properties of their complementary bacteria were basically the same as that of wild type, which indicated that XC2311 XC2223 XCV2304 and XC 1937 were related to the swimming characteristics of the strain. A capillary method was used to detect 30 chemicals (maltose, glucose, fructose, xylose, lactose, sucrose, ribose, arabinose, mannitol, tyrosine, arginine, alanine, leucine, serine, lysine) in Xcc8004. The chemotaxis of tryptophan, threonine, histidine, valine, glutamine, glutamate, aspartic acid, cysteine, proline, phenylalanine, isoleucine, magnesium chloride, calcium chloride, ammonium chloride, citric acid), The results showed that wild type strains were resistant to 18 substances (sucrose, maltose, lactose, ribose, fructose, galactose, xylose, glucose, cysteine, proline, phenylalanine, glutamine, serine, isoleucine, arginine), Leucine, calcium chloride and magnesium chloride have obvious chemotaxis. In order to analyze how the 24 genes affect the chemotaxis of the strains, we analyzed the chemotaxis of these mutants to these 18 substances. Chemotaxis test showed that Xcc8004 has obvious chemotaxis to some carbohydrates, amino acids and inorganic salt ions which are involved in cell life. There was no significant difference in HRR, biofilm, heavy metal resistance and EPS production between these mutants and wild type strains.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S432.4

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