Propagule limitation affects the response of soil methane oxidizer community to increased salinity
Propagule limitation affects the response of soil methane oxidizer community to increased salinity
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DOI：
10.1016/j.geoderma.2022.116082
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发表时间：
2022-08-13
期刊：
影响因子：
6.1
通讯作者：
Liu，Yongqin
中科院分区：
文献类型：
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作者：
Fang，Jie;Adams，Jonathan M.;Liu，Yongqin
繁殖限制在多大程度上可以控制微生物介导的过程(如甲烷氧化)对突然的环境变化的反应，人们对此知之甚少。在这里，我们比较了两个湖泊湖滨土壤中的甲烷微生物群落对实验中盐度增加的反应能力。一组样本来自青藏高原的一个淡水湖(阳湖)的湖滨土壤，另一组样本来自一个微咸的湖泊(青海湖)。将样品加入5%、13CH4或12CH4的∼和不同浓度的NaC l溶液中，在微型宇宙中孵化。采用DNA稳定同位素探测(DNA-SIP)和高通量测序相结合的方法研究了不同盐度湖滨土壤中甲烷营养活性种群的差异。咸水湖和淡水湖的样品在盐度增加时，甲烷氧化能力和甲烷营养活性最初都显著降低。对于盐度为25~50微克/L的淡水样品，加入氯化钠后，7天后没有适应和增加甲烷营养。相比之下，来自微咸水湖的样本显示，甲烷氧化最初是抑制的，几天后甲烷氧化的速度大大增加。测序表明，微咸水湖样品中甲烷营养的恢复与活跃的甲烷菌群落组成的重大转变有关。特别是，Ⅰa型甲烷氧化菌的相对丰度随着盐度的增加而变得更加丰富。看来，在这种淡水湖环境中，与附近任何耐高盐度细菌来源的隔离阻止了完全适应环境高盐度变化的可能性，只有通过从现有群落内进行物种分类才有可能进行适度的盐度适应。相比之下，在高盐度环境中，高耐盐性的甲基微生物能够打破高盐度环境中的建立限制，成为优势甲烷菌。我们的研究提供了一个繁殖限制阻止适应变化条件的实例。
The extent to which propagule limitation can govern the responses of microbially-mediated processes (such as methane oxidation) to sudden environmental changes, is poorly understood. Here, we compared the ability of the methanotroph community in lakeshore soils of two lakes to respond to an experimental increase in salinity. One set of samples was taken from lakeshore soils of a freshwater lake (Yang Lake), the other from a slightly brackish lake (Qinghai Lake), both on the Tibetan Plateau. Samples were incubated in microcosms by adding ∼ 5 %13CH4or12CH4and different concentrations of NaCl solution. DNA stable-isotope probing (DNA-SIP) followed by high-throughput sequencing was used to determine how the active methanotrophic populations differed in lakeshore soils with different salinity levels. Samples from saline and freshwater lake initially showed much-reduced methane oxidation ability and methanotrophic activity at increased salinity. For the freshwater samples with the salinity of 25 to 50 g/L after NaCl addition, there was no adaptation and increase in methanotrophy after 7 days. By contrast, samples from the brackish lake showed an initial depression of methane oxidation, followed by greatly increased rates after several days. Sequencing revealed that this recovery of methanotrophy in the brackish lake samples was associated with a major switchover in composition of active methanotroph community. In particular, the relative abundance of Type Ⅰa methanotrophs became more abundant at increased salinity. It appears that in this freshwater lake environment, isolation from any nearby high-salinity-tolerant bacterial sources has prevented the possibility of full adaptation to a high salinity change in the environment, and only a moderate salinity adaptation is possible by species-sorting from within the existing community. By contrast, in the higher-salinity environment, the highly salinity-tolerantMethylomicrobiumwas able to break the establishment limitation in the high salinity environment and become the dominant methanotroph. Our study provides an instance of propagule limitation preventing adaptation to changed conditions.