Zhang Xuan, Song Xin, Wang Taotao, Huang Lei, Ma Haiyang, Wang Mao, Tan Dunyan
College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China.
State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, College of Ecology, Lanzhou University, Lanzhou, China.
Front Microbiol. 2022 Oct 13;13:1015588. doi: 10.3389/fmicb.2022.1015588. eCollection 2022.
Nitrogen (N) deposition is a worldwide issue caused by human activity. Long-term deposition of N strongly influences plant productivity and community composition. However, it is still unclear how the microbial community responds to long-term N addition in a desert ecosystem. Therefore, a long-term experiment was conducted in the Gurbantonggut Desert in northwestern China in 2015. Four N addition rates, 0 (CK), 5 (N1), 20 (N2), and 80 (N3) kg N ha yr., were tested and the soil was sampled after 6 years of N addition. High-throughput sequencing (HTS) was used to analyze the soil microbial composition. The HTS results showed that N addition had no significant effect on the bacterial α-diversity and β-diversity ( > 0.05) but significantly reduced the archaeal β-diversity ( < 0.05). The fungal Chao1 and ACE indexes in the N2 treatment increased by 24.10 and 26.07%, respectively. In addition, N addition affected the bacterial and fungal community structures. For example, compared to CK, the relative abundance of Actinobacteria increased by 17.80%, and the relative abundance of Bacteroidetes was reduced by 44.46% under N3 treatment. Additionally, N addition also changed the bacterial and fungal community functions. The N3 treatment showed increased relative abundance of nitrate-reducing bacteria (27.06% higher than CK). The relative abundance of symbiotrophic fungi was increased in the N1 treatment (253.11% higher than CK). SOC and NH -N could explain 62% of the changes in the fungal community function. N addition can directly affect the bacterial community function or indirectly through NO -N. These results suggest that different microbial groups may have various responses to N addition. Compared with bacteria and fungi, the effect of N addition was less on the archaeal community. Meanwhile, N-mediated changes of the soil properties play an essential role in changes in the microbial community. The results in the present study provided a reliable basis for an understanding of how the microbial community in a desert ecosystem adapts to long-term N deposition.
氮（N）沉降是一个由人类活动引起的全球性问题。长期的氮沉降会强烈影响植物生产力和群落组成。然而，在沙漠生态系统中，微生物群落如何响应长期的氮添加仍不清楚。因此，2015年在中国西北部的古尔班通古特沙漠进行了一项长期实验。设置了四个氮添加水平，分别为0（对照，CK）、5（N1）、20（N2）和80（N3）千克氮·公顷·年，并在添加氮6年后采集土壤样本。采用高通量测序（HTS）分析土壤微生物组成。HTS结果表明，氮添加对细菌的α多样性和β多样性没有显著影响（P>0.05），但显著降低了古菌的β多样性（P<0.05）。N2处理中真菌的Chao1和ACE指数分别增加了24.10%和26.07%。此外，氮添加影响了细菌和真菌的群落结构。例如，与对照相比，在N3处理下，放线菌的相对丰度增加了17.80%，拟杆菌的相对丰度降低了44.46%。此外，氮添加还改变了细菌和真菌的群落功能。N3处理显示硝酸盐还原菌的相对丰度增加（比对照高27.06%）。共生营养真菌的相对丰度在N1处理中增加（比对照高253.11%）。土壤有机碳（SOC）和铵态氮（NH₄⁺-N）可以解释真菌群落功能变化的62%。氮添加可以直接影响细菌群落功能，也可以通过硝态氮（NO₃⁻-N）间接影响。这些结果表明，不同的微生物类群对氮添加可能有不同的响应。与细菌和真菌相比，氮添加对古菌群落的影响较小。同时，氮介导的土壤性质变化在微生物群落变化中起着至关重要的作用。本研究结果为理解沙漠生态系统中的微生物群落如何适应长期氮沉降提供了可靠依据。
