基于xoxF基因的不同生境下甲醇氧化菌群多样性研究初探
发布时间：2018-08-08 15:38
【摘要】：甲醇是甲烷氧化过程的中间产物,高浓度的甲醇可能会对甲烷单加氧酶产生反馈抑制,从而抑制甲烷的氧化。基于mxaF和xoxF蛋白质序列的系统发育分析结果显示,甲醇脱氢酶蛋白质家族组成至少有六种不同的独立分支(mxaF和xoxFl-5)。而xoxF基因是最近新发现的甲基营养菌的甲醇脱氢酶。虽然,在海洋环境中利用xoxF基因检测到多种甲醇氧化菌,但在湿地沉积物和草原土壤中的多样性及分布还尚无报道。为了解湿地沉积物及草原土壤中甲醇氧化菌的多样性,本文以内蒙古高原典型湿地和草原作为研究区域,选择重度富营养化的乌梁素海湿地、半干旱区锡林河水库、锡林河围封湿地,以及典型草原毛登牧场,采集表层土壤或沉积物作为研究对象,提取样品总DNA并构建xoxF5基因克隆文库,共测序221个克隆子序列(132个OTUs)并进行甲醇氧化菌群落结构及多样性分析。研究结果如下:(1)三个不同湿地沉积物中都检测出α-变形菌门(丰度:12～48%,下同),β-变形菌门(7～47%),γ 变形菌门(37～54%)的甲醇氧化菌,生境不同而有所差异。在属水平上,Type Ⅰ甲烷氧化菌(Cluster 6和Cluster 8)是同时作为乌梁素海(WWT),锡林河水库(XRR),锡林河湿地(XWT)的主要菌群(丰度分别17%,38%及22%)。其次,Hyphomicrobium属相关的Cluster 3B是乌梁素海(WWT)和锡林河水库(XRR)中的丰度较高(分别22%和41%)。而Methylibium sp.Root1272亲缘菌群(OTU005)是锡林河湿地(XWT)特异的优势菌(16%)。还有,Beggiatoa相关Cluster 4(17%)也是乌梁素海特异性主要菌群。这些结果显示,甲烷氧化菌也是湿地主要甲醇氧化菌,可能为其他氮或硫循环功能的甲醇氧化菌提供碳素营养。(2)毛登牧场草原土壤的甲醇氧化菌中包含α-变形菌门(63%),β-变形菌门(13%),γ-变形菌门(5%),厚壁菌门(17%)及放线菌门(2%)。其中,α-变形菌门的Hyphomicrobiu 相关 Cluster 3B(16%)和Bradyrhizobi m亲缘 Cluster 3A(23%),以及未知的厚壁菌门的未知的Cluster 5(20%)是主要功能菌群,另外γ-变形菌门的Type Ⅰ甲烷氧化菌(4%)。而且与湿地相比,Bradyrhizobium与未知的Cluster 5是草原特异菌群,在草原土壤中甲醇氧化菌可能对草原土壤氮循环起重要作用。(3)甲醇氧化菌的多样性分析结果是毛登草原的香农指数最高(H'=3.62),依次是锡林河湿地(3.32),锡林河水库(3.18),乌梁素海湿地(2.88)。RDA分析结果表明,总磷,铵态氮及pH可能对甲醇氧化菌群组分及多样性有一定的影响。
[Abstract]:Methanol is the intermediate product of methane oxidation, and high concentration of methanol may inhibit the oxidation of methane by feedback inhibition of methane monooxygenase. Phylogenetic analysis based on mxaF and xoxF protein sequences showed that there were at least six distinct branches (mxaF and xoxFl-5) of methanol dehydrogenase protein family. The xoxF gene is a newly discovered methanol dehydrogenase of methyl nutrition bacteria. Although a variety of methanol-oxidizing bacteria were detected by xoxF gene in marine environment, the diversity and distribution of methanol-oxidizing bacteria in wetland sediments and steppe soils have not been reported. In order to understand the diversity of methanol-oxidizing bacteria in wetland sediment and steppe soil, the typical wetland and steppe in Inner Mongolia Plateau were selected as the study area, the Wuliangsuhai wetland with heavy eutrophication and the Xilin River reservoir in semi-arid area were selected. The Xilin River enclosed wetland and typical grassland Maoden pasture were collected from the surface soil or sediment as the research object, the total DNA of the sample was extracted and the xoxF5 gene clone library was constructed. 221 clone sequences (132 OTUs) were sequenced and the community structure and diversity of methanol-oxidizing bacteria were analyzed. The results are as follows: (1) the methanol-oxidizing bacteria of 伪 -Proteus (abundance 12: 48, the same below), 尾 -Proteus (747%) and 纬 -Proteus (3754%) were detected in three different wetland sediments, with different habitats. At the generic level, methane-oxidizing bacteria (Cluster _ 6 and Cluster _ 8) are the main flora (abundance 17 38% and 22%) of (XWT) in (XRR), Xilin River wetland of (WWT), Xilin River Reservoir in Wuliangsuhai. The relative Cluster 3B of Hyphomicrobium was higher in (WWT) and Xilin Reservoir (22% and 41%, respectively). Methylibium sp.Root1272 phylogeny (OTU005) was the dominant strain of (XWT) in Xilin River wetland (16%). Beggiatoa related Cluster 4 (17%) is also the main specific flora of Uliangsuhai. These results show that methanogens are also the main methanol-oxidizing bacteria in wetlands. It may provide carbon nutrition for other methanol-oxidizing bacteria with nitrogen or sulfur cycling function. (2) Methanol-oxidizing bacteria in Maoden pastureland soil include 伪 -Proteus (63%), 尾 -Proteus (13%), 纬 -Proteus (5%), P. thuringiensis (17%) and Actinomycetes (2%). Among them, Hyphomicrobiu associated Cluster 3B (16%) and Bradyrhizobi m related Cluster 3A (23%) and unknown Cluster 5 (20%) of 伪 -Proteus phylum were the main functional flora, and Type 鈪，
本文编号：2172241
[Abstract]:Methanol is the intermediate product of methane oxidation, and high concentration of methanol may inhibit the oxidation of methane by feedback inhibition of methane monooxygenase. Phylogenetic analysis based on mxaF and xoxF protein sequences showed that there were at least six distinct branches (mxaF and xoxFl-5) of methanol dehydrogenase protein family. The xoxF gene is a newly discovered methanol dehydrogenase of methyl nutrition bacteria. Although a variety of methanol-oxidizing bacteria were detected by xoxF gene in marine environment, the diversity and distribution of methanol-oxidizing bacteria in wetland sediments and steppe soils have not been reported. In order to understand the diversity of methanol-oxidizing bacteria in wetland sediment and steppe soil, the typical wetland and steppe in Inner Mongolia Plateau were selected as the study area, the Wuliangsuhai wetland with heavy eutrophication and the Xilin River reservoir in semi-arid area were selected. The Xilin River enclosed wetland and typical grassland Maoden pasture were collected from the surface soil or sediment as the research object, the total DNA of the sample was extracted and the xoxF5 gene clone library was constructed. 221 clone sequences (132 OTUs) were sequenced and the community structure and diversity of methanol-oxidizing bacteria were analyzed. The results are as follows: (1) the methanol-oxidizing bacteria of 伪 -Proteus (abundance 12: 48, the same below), 尾 -Proteus (747%) and 纬 -Proteus (3754%) were detected in three different wetland sediments, with different habitats. At the generic level, methane-oxidizing bacteria (Cluster _ 6 and Cluster _ 8) are the main flora (abundance 17 38% and 22%) of (XWT) in (XRR), Xilin River wetland of (WWT), Xilin River Reservoir in Wuliangsuhai. The relative Cluster 3B of Hyphomicrobium was higher in (WWT) and Xilin Reservoir (22% and 41%, respectively). Methylibium sp.Root1272 phylogeny (OTU005) was the dominant strain of (XWT) in Xilin River wetland (16%). Beggiatoa related Cluster 4 (17%) is also the main specific flora of Uliangsuhai. These results show that methanogens are also the main methanol-oxidizing bacteria in wetlands. It may provide carbon nutrition for other methanol-oxidizing bacteria with nitrogen or sulfur cycling function. (2) Methanol-oxidizing bacteria in Maoden pastureland soil include 伪 -Proteus (63%), 尾 -Proteus (13%), 纬 -Proteus (5%), P. thuringiensis (17%) and Actinomycetes (2%). Among them, Hyphomicrobiu associated Cluster 3B (16%) and Bradyrhizobi m related Cluster 3A (23%) and unknown Cluster 5 (20%) of 伪 -Proteus phylum were the main functional flora, and Type 鈪，
本文编号：2172241
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