本文選題：西瓜嗜酸菌　切入點(diǎn)：趨化性　出處：《中國農(nóng)業(yè)科學(xué)院》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：瓜類細(xì)菌性果斑病(Bacterial Fruit Blotch,簡稱BFB)是世界范圍的檢疫性細(xì)菌病害,主要為害西瓜、甜瓜等葫蘆科作物,造成重大的經(jīng)濟(jì)損失。西瓜嗜酸菌(Acidovorax citrulli,Schaad et al,2008)是其病原菌,有研究表明病原細(xì)菌在寄主表面的定殖能力與其致病能力關(guān)系密切,而病原細(xì)菌的趨化能力是決定定殖能力的關(guān)鍵因素之一。本研究主要圍繞西瓜嗜酸菌的趨化性測定及其趨化基因的功能展開,主要結(jié)果如下:1、初步測定西瓜嗜酸菌Ac-5菌株的趨化性利用毛細(xì)管法測定碳源、氨基酸、有機(jī)酸等對西瓜嗜酸菌趨化性的影響。結(jié)果發(fā)現(xiàn):麥芽糖、葡萄糖、乳糖、蔗糖和半乳糖顯著促進(jìn)西瓜嗜酸菌的趨化性;L-亮氨酸、L-異亮氨酸、L-色氨酸、L-纈氨酸、L-脯氨酸、L-谷氨酸和L-谷氨酰胺顯著促進(jìn)西瓜嗜酸菌的趨化性,而L-蛋氨酸顯著抑制其趨化性;檸檬酸和蘋果酸顯著促進(jìn)西瓜嗜酸菌的趨化性;氯化鈉、硫酸鎂等對西瓜嗜酸菌的趨化性無顯著影響。2、Ac-5菌株趨化基因che A和che Y的生物信息學(xué)分析登錄NCBI數(shù)據(jù)庫西瓜嗜酸菌全基因序列查找che A和che Y基因的相關(guān)信息。che A和che Y基因分別編碼Che A和Che Y蛋白。Che A和Che Y蛋白均存在多個(gè)疏水性氨基酸區(qū)域;Che A蛋白是一種跨膜蛋白,在600-700氨基酸處(即Che W結(jié)合區(qū)域)有跨膜結(jié)構(gòu),Che Y蛋白不存在跨膜結(jié)構(gòu),是一種膜內(nèi)蛋白,用于接收Che A蛋白的信號;西瓜嗜酸菌Che A蛋白與青枯菌的Che A蛋白親緣關(guān)系最近,和熒光假單胞菌的親緣關(guān)系最遠(yuǎn)。3、Ac-5菌株趨化基因che A和che Y3的功能研究構(gòu)建Δche A和Δche Y3基因缺失突變株以及Cche A互補(bǔ)菌株,并進(jìn)行表型分析。結(jié)果發(fā)現(xiàn):Δche A和Δche Y3基因缺失突變株與野生型菌Ac-5相比,趨化及運(yùn)動(dòng)能力下降;在種子表面的定殖能力下降;病株病情指數(shù)先下降后恢復(fù)野生型菌株Ac-5水平;生物膜形成能力增強(qiáng);引起非寄主煙草的過敏性反應(yīng)。4、che A基因缺失對其他基因表達(dá)量的影響利用熒光定量PCR分析che A基因缺失對其他基因表達(dá)量的影響。結(jié)果顯示che A基因在突變株中不表達(dá),T3SS中hrc N和hrp E基因,毒性蛋白trb C和vir B基因,鞭毛合成基因mot A和動(dòng)力蛋白基因fli M以及信號接收蛋白基因che Y1均上調(diào)表達(dá)。
[Abstract]:Bacterial Fruit blotch (BFB) is a quarantine bacterial disease in the world, which mainly damages watermelon, muskmelon and other cucurbitaceae crops and causes great economic losses. Acidovorax citrullirii Schaad et Alba 2008 is the pathogen of this disease. Some studies have shown that the colonization ability of pathogenic bacteria on the host surface is closely related to its pathogenicity. The chemotactic ability of pathogenic bacteria is one of the key factors to determine colonization ability. This study focused on the chemotaxis of eosinophilic bacteria in watermelon and the function of chemoattractant genes. The main results were as follows: 1. The chemotaxis of watermelon acidophilic strain Ac-5 was determined by capillary method. The effects of carbon sources, amino acids and organic acids on the chemotaxis of watermelon acidophilic bacteria were determined by capillary method, and the results showed that: maltose, glucose, lactose, Sucrose and galactose promoted the chemotaxis of watermelon acidophilic bacteria significantly. L- leucine, L-leucine, L-tryptophan, L-valine, L-proline, L-glutamine, and L-glutamine significantly promoted the chemotaxis of watermelon acidophilic bacteria. L-methionine significantly inhibited its chemotaxis; citric acid and malic acid significantly promoted the chemotaxis of acidophilic bacteria in watermelon; Bioinformatics analysis of chemotaxis genes che A and che Y of Ac-5 strain in watermelon; bioinformatics analysis of the chemoattractant genes che A and che Y of watermelon strain Ac-5; access to the whole gene sequence of eosinophilic bacteria in watermelon in NCBI database to find the relevant information of che A and che Y genes. The A and che Y genes encode Che A and Che Y proteins. CHE A and Che Y proteins have many hydrophobic amino acid regions. CHE A protein is a transmembrane protein. At 600-700 amino acids (i.e., Che W binding region), the transmembrane structure of Che Y protein is not transmembrane structure, it is a kind of intramembrane protein, which is used to receive the signal of Che A protein, and the relationship between Che A protein of watermelon acidophilic bacteria and Che A protein of bacterial wilt is very close. The function of chemoattractant genes che A and che Y3 of Ac-5 strain was the furthest related to Pseudomonas fluorescein. The deletion mutants of 螖 che A and 螖 che Y3 genes and the complementary strain Cche A were constructed. The results of phenotypic analysis showed that the chemotaxis and motor ability of 螖 che A and 螖 che Y3 mutant were lower than those of wild type strain Ac-5, the colonization ability on seed surface was decreased, the disease index of disease plant was decreased first, and then the Ac-5 level of wild type strain was restored. The ability of biofilm formation was enhanced; Effects of allergy. 4che A gene deletion on the expression of other genes in non-host tobacco the effect of che A gene deletion on the expression of other genes was analyzed by fluorescence quantitative PCR. The results showed that the che A gene was expressed in mutant strains. Hrc N and hrp E genes were not expressed in T3SS. The expression of trb C and vir B genes, flagellum synthase gene mot A, dynamic protein gene fli M and signal receptor-protein gene che Y1 were up-regulated.
【學(xué)位授予單位】：中國農(nóng)業(yè)科學(xué)院
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S432.4

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相關(guān)期刊論文 前1條

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本文編號：1610872