Molecular Analyses of the Methane-Oxidizing Microbial Community in Rice Field Soil by Targeting the Genes of the 16S rRNA, Particulate Methane Monooxygenase, and Methanol Dehydrogenase

作者：Thilo Henckel, Michael W. Friedrich, Ralf Conrad · 发表于：Applied and Environmental Microbiology · 年份：1999 · DOI：10.1128/aem.65.5.1980-1990.1999 · 被引用次数：336 · 研究领域：Microbial metabolism and enzyme function、Anaerobic Digestion and Biogas Production、Methane Hydrates and Related Phenomena

Rice field soil with a nonsaturated water content induced CH4 consumption activity when it was supplemented with 5% CH4. After a lag phase of 3 days, CH4 was consumed rapidly until the concentration was less than 1.8 parts per million by volume (ppmv). However, the soil was not able to maintain the oxidation activity at near-atmospheric CH4 mixing ratios (i.e., 5 ppmv). The soil microbial community was monitored by performing denaturing gradient gel electrophoresis (DGGE) during the oxidation process with different PCR primer sets based on the 16S rRNA gene and on functional genes. A universal small-subunit (SSU) ribosomal DNA (rDNA) primer set and 16S rDNA primer sets specifically targeting type I methylotrophs (members of the gamma subdivision of the class Proteobacteria [gamma-Proteobacteria]) and type II methylotrophs (members of the alpha-Proteobacteria) were used. Functional PCR primers targeted the genes for particulate methane monooxygenase (pmoA) and methanol dehydrogenase (mxaF), which code for key enzymes in the catabolism of all methanotrophs. The yield of PCR products amplified from DNA in soil that oxidized CH4 was the same as the yield of PCR products amplified from control soil when the universal SSU rDNA primer set was used but was significantly greater when primer sets specific for methanotrophs were used. The DGGE patterns and the sequences of major DGGE bands obtained with the universal SSU rDNA primer set showed that the community structure was dominated ...