School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, USA
Department of Biology, College of Arts and Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Appl Environ Microbiol. 2018 Apr 16;84(9). doi: 10.1128/AEM.02816-17. Print 2018 May 1.
Here, we present evidence that ca. 20 years of experimental N deposition altered the composition of lignin-decaying class II peroxidases expressed by forest floor fungi, a response which has occurred concurrently with reductions in plant litter decomposition and a rapid accumulation of soil organic matter. This finding suggests that anthropogenic N deposition has induced changes in the biological mediation of lignin decay, the rate limiting step in plant litter decomposition. Thus, an altered composition of transcripts for a critical gene that is associated with terrestrial C cycling may explain the increased soil C storage under long-term increases in anthropogenic N deposition. Fungal class II peroxidases are enzymes that mediate the rate-limiting step in the decomposition of plant material, which involves the oxidation of lignin and other polyphenols. In field experiments, anthropogenic N deposition has increased soil C storage in forests, a result which could potentially arise from anthropogenic N-induced changes in the composition of class II peroxidases expressed by the fungal community. In this study, we have gained unique insight into how anthropogenic N deposition, a widespread agent of global change, affects the expression of a functional gene encoding an enzyme that plays a critical role in a biologically mediated ecosystem process.
在这里，我们提供的证据表明，大约 20 年的实验性氮沉积改变了森林地表真菌表达的木质素分解 II 型过氧化物酶的组成，这种反应与植物凋落物分解的减少和土壤有机质的快速积累同时发生。这一发现表明，人为氮沉积已经诱导了木质素分解的生物中介变化，这是植物凋落物分解的限速步骤。因此，与陆地碳循环相关的关键基因的转录本组成的改变可能解释了在人为氮沉积长期增加下土壤碳储存的增加。真菌 II 型过氧化物酶是一种酶，它介导植物材料分解的限速步骤，涉及木质素和其他多酚的氧化。在野外实验中，人为氮沉积增加了森林土壤中的碳储存，这一结果可能源于人为氮引起的真菌群落表达的 II 型过氧化物酶组成的变化。在这项研究中，我们深入了解了全球变化的广泛因素——人为氮沉积如何影响编码在生物中介生态系统过程中起关键作用的酶的功能基因的表达。
