Yu Julian, Pavia Michael J, Deem Lauren M, Crow Susan E, Deenik Jonathan L, Penton Christopher Ryan
School of Life Sciences, Arizona State University, Tempe, AZ, United States.
Center for Fundamental and Applied Microbiomics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States.
Front Microbiol. 2020 Nov 17;11:587972. doi: 10.3389/fmicb.2020.587972. eCollection 2020.
The functions and interactions of individual microbial populations and their genes in agricultural soils amended with biochar remain elusive but are crucial for a deeper understanding of nutrient cycling and carbon (C) sequestration. In this study, we coupled DNA stable isotope probing (SIP) with shotgun metagenomics in order to target the active community in microcosms which contained soil collected from biochar-amended and control plots under napiergrass cultivation. Our analyses revealed that the active community was composed of high-abundant and low-abundant populations, including , and . Although biochar did not significantly shift the active taxonomic and functional communities, we found that the (nitrate reductase) gene was significantly more abundant in the control metagenomes. Interestingly, putative denitrifier genomes generally encoded one gene or a partial denitrification pathway, suggesting denitrification is typically carried out by an assembly of different populations within this Oxisol soil. Altogether, these findings indicate that the impact of biochar on the active soil microbial community are transient in nature. As such, the addition of biochar to soils appears to be a promising strategy for the long-term C sequestration in agricultural soils, does not impart lasting effects on the microbial functional community, and thus mitigates un-intended microbial community shifts that may lead to fertilizer loss through increased N cycling.
在添加生物炭的农业土壤中，单个微生物种群及其基因的功能和相互作用仍不清楚，但对于深入理解养分循环和碳（C）固存至关重要。在本研究中，我们将DNA稳定同位素探测（SIP）与鸟枪法宏基因组学相结合，以靶向含有从象草种植下生物炭改良和对照地块采集的土壤的微观世界中的活跃群落。我们的分析表明，活跃群落由高丰度和低丰度种群组成，包括 、 和 。虽然生物炭没有显著改变活跃的分类和功能群落，但我们发现 （硝酸还原酶）基因在对照宏基因组中明显更为丰富。有趣的是，推定的反硝化菌基因组通常编码一个基因或部分反硝化途径，这表明反硝化作用通常由这种氧化土中的不同种群组合进行。总之，这些发现表明生物炭对活跃土壤微生物群落的影响本质上是短暂的。因此，向土壤中添加生物炭似乎是农业土壤长期碳固存的一种有前景的策略，不会对微生物功能群落产生持久影响，从而减轻可能因氮循环增加导致肥料损失的意外微生物群落变化。
