Interactions among plants, bacteria, and fungi reduce extracellular enzyme activities under long-term N fertilization.
Interactions among plants, bacteria, and fungi reduce extracellular enzyme activities under long-term N fertilization.
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DOI：
10.1111/gcb.14081
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发表时间：
2018-06
影响因子：
11.6
通讯作者：
Brzostek ER
中科院分区：
文献类型：
--
作者：
Carrara JE;Walter CA;Hawkins JS;Peterjohn WT;Averill C;Brzostek ER
大气氮沉降增加了温带森林土壤碳储量。大多数研究认为，这些土壤碳收益主要是由真菌群落组成的变化与高氮导致木质素降解担子菌下降。然而，最近的研究表明，植物和土壤微生物是动态交织在一起的，植物通过向根际微生物提供碳补贴来提高酶的产生和氮的动员。因此，在高氮，树木可能会减少地下C分配导致级联影响的微生物降解土壤有机质的能力，通过微生物物种的转变和/或植物-微生物相互作用的变化。本研究的目的是确定在何种程度上耦合植物，真菌和细菌的N施肥反应改变酶的活性，是土壤分解的主要代理商。我们测量了真菌和细菌群落组成，根微生物的相互作用，并在根际，散装和有机层的土壤采样的长期（>25年），全流域，在美国西弗吉尼亚州的Fernow实验森林的N施肥实验中的胞外酶活性。我们观察到植物碳投资细根生物量（24.7%），根形态和丛枝菌根（AM）定植（55.9%）显着下降。此外，我们发现细胞外酶活性的下降与细菌群落组成的变化显着相关，但与真菌群落组成的变化无关。这种细菌群落的变化也与减少AM真菌定植，表明植物投资地下驱动器的响应，细菌群落结构和功能的N施肥下降。总的来说，我们发现，酶活性对氮肥的反应不仅仅是由真菌驱动的，而是反映了整个生态系统的反应，即地下C投资的强度下降，通过土壤环境获得N级联。
Atmospheric nitrogen (N) deposition has enhanced soil carbon (C) stocks in temperate forests. Most research has posited that these soil C gains are driven primarily by shifts in fungal community composition with elevated N leading to declines in lignin degrading Basidiomycetes. Recent research, however, suggests that plants and soil microbes are dynamically intertwined, whereby plants send C subsidies to rhizosphere microbes to enhance enzyme production and the mobilization of N. Thus, under elevated N, trees may reduce belowground C allocation leading to cascading impacts on the ability of microbes to degrade soil organic matter through a shift in microbial species and/or a change in plant–microbe interactions. The objective of this study was to determine the extent to which couplings among plant, fungal, and bacterial responses to N fertilization alter the activity of enzymes that are the primary agents of soil decomposition. We measured fungal and bacterial community composition, root–microbial interactions, and extracellular enzyme activity in the rhizosphere, bulk, and organic horizon of soils sampled from a long-term (>25 years), whole-watershed, N fertilization experiment at the Fernow Experimental Forest in West Virginia, USA. We observed significant declines in plant C investment to fine root biomass (24.7%), root morphology, and arbuscular mycorrhizal (AM) colonization (55.9%). Moreover, we found that declines in extracellular enzyme activity were significantly correlated with a shift in bacterial community composition, but not fungal community composition. This bacterial community shift was also correlated with reduced AM fungal colonization indicating that declines in plant investment below-ground drive the response of bacterial community structure and function to N fertilization. Collectively, we find that enzyme activity responses to N fertilization are not solely driven by fungi, but instead reflect a whole ecosystem response, whereby declines in the strength of belowground C investment to gain N cascade through the soil environment.
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DOI：
10.1038/ismej.2011.159
发表时间：
2012-05
期刊：
The ISME journal
影响因子：
--
作者：
通讯作者：
--
影响因子：
3.7
作者：
Bae, Kikang;Fahey, Timothy J.;Fisk, Melany
通讯作者：
Fisk, Melany
影响因子：
2.7
作者：
Burnham, Mark B.;Cumming, Jonathan R.;Peterjohn, William T.
通讯作者：
Peterjohn, William T.
影响因子：
3.7
作者：
Brzostek, Edward R.;Fisher, Joshua B.;Phillips, Richard P.
通讯作者：
Phillips, Richard P.
影响因子：
10.1
作者：
Olson, DM;Dinerstein, E;Kassem, KR
通讯作者：
Kassem, KR