Department of Ecological Microbiology, University of Bayreuth, 95440 Bayreuth, Germany.
Environ Microbiol Rep. 2009 Oct;1(5):336-46. doi: 10.1111/j.1758-2229.2009.00047.x. Epub 2009 Jul 14.
Aerobic methanotrophs in forest soils are the largest biological sink for atmospheric methane (CH4 ). Community structures in 53 soils from Europe, Russia, North and South America, Asia and New Zealand located in boreal, temperate and tropical forests were analysed and maximal abundances of 2.1 × 10(7) methanotrophs g(-1) DW were measured. In acidic soils, the most frequently detected pmoA genotypes were Upland Soil Cluster α (USCα) and Methylocystis spp. Phospholipid fatty acids that were labelled by consumption of (14/13) CH4 suggested the activity of type II methanotrophs. Cluster 1 (Methylocystaceae), USCγ and Methylocystis spp. were frequently detected genotypes in pH-neutral soils. Genotypes with ambiguous functional affiliation were co-detected (Clusters MR1, RA21, 2) and may represent aerobic methanotrophs, ammonia oxidizers or enzymes with an unknown function. The physiological traits of atmospheric CH4 oxidizers are largely unknown because organisms possessing the key forest soil pmoA genotypes (USCα, USCγ, Cluster 1) have not been cultivated. Some methanotrophic strains belonging to the family Methylocystaceae have been shown to oxidize CH4 at atmospheric mixing ratios. Methylocystis strain SC2 was found to have an alternative particulate CH4 monooxygenase responsible for CH4 oxidation at atmospheric mixing ratios. pH, forest type and temperature might be environmental factors that shape methanotrophic communities in forest soils. However, specific effects on individual species are largely unknown, and only a limited number of studies have addressed environmental controls of methanotrophic diversity, pointing to the need for future research in this area.
森林土壤中的好氧甲烷营养菌是大气甲烷（CH4）的最大生物汇。分析了来自欧洲、俄罗斯、北美和南美、亚洲和新西兰的 53 个土壤样本中的群落结构，这些土壤分别位于北方森林、温带森林和热带森林中，测量到的最大甲烷营养菌丰度为 2.1×10(7)个甲烷营养菌 g(-1) 干重。在酸性土壤中，最常检测到的 pmoA 基因型是旱地土壤聚类 α（USCα）和甲基单胞菌属。通过消耗（14/13）CH4 标记的磷脂脂肪酸表明了 II 型甲烷营养菌的活性。在 pH 值中性的土壤中，经常检测到聚类 1（甲基单胞菌科）、USCγ 和甲基单胞菌属的基因型。具有模糊功能归属的基因型被共同检测到（聚类 MR1、RA21、2），可能代表好氧甲烷营养菌、氨氧化菌或具有未知功能的酶。大气 CH4 氧化菌的生理特性在很大程度上是未知的，因为拥有关键森林土壤 pmoA 基因型（USCα、USCγ、聚类 1）的生物体尚未被培养。一些属于甲基单胞菌科的甲烷营养菌株已被证明能够在大气混合比下氧化 CH4。发现甲基单胞菌菌株 SC2 具有替代的颗粒态 CH4 单加氧酶，负责在大气混合比下氧化 CH4。pH 值、森林类型和温度可能是塑造森林土壤中甲烷营养菌群落的环境因素。然而，对单个物种的具体影响在很大程度上是未知的，只有少数研究探讨了甲烷营养菌多样性的环境控制，这表明需要在该领域进行未来的研究。
