Diversity of Methane-Oxidizing Bacteria in Soils from "Hot Lands of Medolla" (Italy) Featured by Anomalous High-Temperatures and Biogenic CO(2) Emission.
Diversity of Methane-Oxidizing Bacteria in Soils from "Hot Lands of Medolla" (Italy) Featured by Anomalous High-Temperatures and Biogenic CO(2) Emission.
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DOI：
10.1264/jsme2.me16087
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发表时间：
2016-12-23
影响因子：
2.2
通讯作者：
Fedi S
中科院分区：
文献类型：
--
作者：
Cappelletti M;Ghezzi D;Zannoni D;Capaccioni B;Fedi S
Terre Calde di Medolla“(字面意思是”Medolla的热土“)指的是意大利的一个农业区，那里温度异常高，生物排放的二氧化碳与从0.7米深到地表的CH4氧化过程有关。在此，我们评估了在峰值温度检测到的深度(0.6米)采集的土壤样本中总细菌群落的组成和甲烷氧化细菌(MOB)的多样性。采用与培养无关的方法，如：1)16SRRNA基因和pmoA(编码颗粒甲烷单加氧酶α亚基)基因的克隆文库分析；2)末端限制性片段长度多态性指纹分析。16S rRNA基因分析评估了在0.6米深处采集的中药样品中放线杆菌、酸性细菌、变形杆菌和芽孢杆菌的优势，以及甲烷养生菌(甲基局灶菌和甲氧杆菌)和甲氧菌(甲氧杆菌)的存在。PmoA序列的系统发育分析表明，除了尚未培养的和尚未鉴定的甲烷氧化细菌外，还存在与甲基单胞菌、甲基囊藻属、甲基球菌属和甲基局灶菌有关的MOB。Jaccard对不同地表深度的T-RFLP剖面的分析表明，0.6m和0.7m深度的土壤样品具有相似的MOB组成，而这些样品与2.5m深度的土壤样品之间的相似性较弱，而2.5m深度的土壤样品中不存在甲基局草属。这些结果将“Terre Calde di Medolla”养殖区的异常高温与微生物甲烷氧化细菌的存在联系在一起。
“Terre Calde di Medolla” (TCM) (literally, “Hot Lands of Medolla”) refers to a farming area in Italy with anomalously high temperatures and diffuse emissions of biogenic CO2, which has been linked to CH4 oxidation processes from a depth of 0.7 m to the surface. We herein assessed the composition of the total bacterial community and diversity of methane-oxidizing bacteria (MOB) in soil samples collected at a depth at which the peak temperature was detected (0.6 m). Cultivation-independent methods were used, such as: i) a clone library analysis of the 16S rRNA gene and pmoA (coding for the α-subunit of the particulate methane monooxygenase) gene, and ii) Terminal Restriction Fragment Length Polymorphism (T-RFLP) fingerprinting. The 16S rRNA gene analysis assessed the predominance of Actinobacteria, Acidobacteria, Proteobacteria, and Bacillus in TCM samples collected at a depth of 0.6 m along with the presence of methanotrophs (Methylocaldum and Methylobacter) and methylotrophs (Methylobacillus). The phylogenetic analysis of pmoA sequences showed the presence of MOB affiliated with Methylomonas, Methylocystis, Methylococcus, and Methylocaldum in addition to as yet uncultivated and uncharacterized methanotrophs. Jaccard’s analysis of T-RFLP profiles at different ground depths revealed a similar MOB composition in soil samples at depths of 0.6 m and 0.7 m, while this similarity was weaker between these samples and those taken at a depth of 2.5 m, in which the genus Methylocaldum was absent. These results correlate the anomalously high temperatures of the farming area of “Terre Calde di Medolla” with the presence of microbial methane-oxidizing bacteria.