Phosphate addition increases tropical forest soil respiration primarily by deconstraining microbial population growth
Phosphate addition increases tropical forest soil respiration primarily by deconstraining microbial population growth
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DOI：
10.1016/j.soilbio.2018.11.026
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发表时间：
2019-03
影响因子：
9.7
通讯作者：
E. Johnston;Minjae Kim;J. Hatt;J. Phillips;Q. Yao;Yang Song;T. Hazen;M. Mayes;K. Konstantinidis
中科院分区：
文献类型：
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作者：
E. Johnston;Minjae Kim;J. Hatt;J. Phillips;Q. Yao;Yang Song;T. Hazen;M. Mayes;K. Konstantinidis
热带生态系统是大气CO2的重要汇，然而，植物生长受到磷（P）可用性的限制。虽然土壤微生物群促进有机磷周转和无机磷动员，其在碳-磷耦合过程中的作用仍然知之甚少。为了推进这一主题，在受控的实验室条件下，将从波多黎各的埃尔云克国家森林中代表高度风化的热带土壤的四个地点收集的土壤与外源性PO 43-一起孵育。P修正案增加CO2呼吸14-23%，相对于控制孵化土壤采样，但最大的总和生物可利用的土壤P. Metatranscriptomics的网站显示，参与细胞生长和吸收其他营养素的基因的相对转录的增加，以响应P修正案。一种新的方法来规范化基因表达的人口水平的相对（DNA）丰度显示，增加转录的细胞生长和分裂基因与磷修正的模式是社区范围内的。磷胁迫下，土壤中α-葡萄糖基多糖生物合成基因相对丰度较高，表明磷胁迫下碳储量增加。调控α-葡萄糖基多糖降解的磷酸化酶基因也更丰富，并且随着P修正的相对转录增加，表明从能量储存向生长的转变。相反，在土壤中的微生物群落不响应磷修正被发现有不稳定的植物来源的底物，如β-葡萄糖基多糖的磷酸解调节代谢。总的来说，我们的研究结果提供了定量的估计增加土壤呼吸后缓解磷的限制，并阐明了一些潜在的生态和分子机制参与这种反应。
Tropical ecosystems are an important sink for atmospheric CO2; however, plant growth is restricted by phosphorus (P) availability. Although soil microbiota facilitate organic P turnover and inorganic P mobilization, their role in carbon-phosphorus coupled processes remains poorly understood. To advance this topic, soils collected from four sites representing highly weathered tropical soils in the El Yunque National Forest, Puerto Rico were incubated with exogenous PO43−under controlled laboratory conditions. P amendment increased CO2respiration by 14–23% relative to control incubations for soils sampled from all but the site with the greatest total and bioavailable soil P. Metatranscriptomics revealed an increase in the relative transcription of genes involved in cell growth and uptake of other nutrients in response to P amendment. A new methodology to normalize gene expression by population-level relative (DNA) abundance revealed that the pattern of increased transcription of cell growth and division genes with P amendment was community-wide. Soil communities responsive to P amendment possessed a greater relative abundance of α-glucosyl polysaccharide biosynthesis genes, suggestive of enhanced C storage under P-limiting conditions. Phosphorylase genes governing the degradation of α-glucosyl polysaccharides were also more abundant and increased in relative transcription with P amendment, indicating a shift from energy storage towards growth. Conversely, microbial communities in soils nonresponsive to P amendment were found to have metabolisms tuned for the phosphorolysis of labile plant-derived substrates, such as β-glucosyl polysaccharides. Collectively, our results provided quantitative estimates of increased soil respiration upon alleviation of P constraints and elucidated several underlying ecological and molecular mechanisms involved in this response.