College of Resources and Environment, Northeast Agricultural University, Harbin 150030, China.
Institute of Natural Resources and Ecology, Heilongjiang Academy of Sciences, Harbin 150040, China.
Bioresour Technol. 2023 Jan;367:128235. doi: 10.1016/j.biortech.2022.128235. Epub 2022 Nov 1.
This study explored the coupling relationships between denitrifiers and N-transformation using multi-level (DNA, RNA and enzyme) and multi-aspect (abundance, diversity, structure, key community, network pattern, and functional module) analyses during cattle-manure (CM) and biochar (CMB) composting. Amino sugar-N (ASN, 0.914) and hydrolysable unknown-N (-0.724) were main organic-N components mediating NH-N in CM and CMB, respectively. Biochar lowered nirK, nirS, and nosZ genes copies, up-regulated nir gene transcripts, and inhibited nitrite reductase (NIR) activity. For nirK-denitrifiers, Luteimonas was predominant taxa influencing NO-N and amino acid-N (AAN). Unclassified_k_norank_d_Bacteria and unclassified_p_Proteobacteria regulated NO-N and ASN, respectively. These three genera played crucial roles in mediating NIR activity and nosZ/nirK. For nirS-denitrifiers, Paracoccus and Pseudomonas mediated NH-N and AAN, respectively, and they were vital genera regulating NO-N, ASN and NIR activity. Furthermore, nirK-denitrifiers was major contributor to denitrification. Overall, functional denitrifiers might simultaneously participate in multiple N-transformation processes.
本研究采用多层次（DNA、RNA 和酶）和多方面（丰度、多样性、结构、关键群落、网络模式和功能模块）分析方法，探讨了反硝化菌与 N 转化之间的偶联关系，在牛粪（CM）和生物炭（CMB）堆肥过程中。氨基糖-N（ASN，0.914）和可水解未知-N（-0.724）是分别介导 CM 和 CMB 中 NH-N 的主要有机-N 成分。生物炭降低了 nirK、nirS 和 nosZ 基因拷贝数，上调了 nir 基因转录物，并抑制了亚硝酸盐还原酶（NIR）活性。对于 nirK-反硝化菌，Luteimonas 是影响 NO-N 和氨基酸-N（AAN）的主要分类群。未分类_k_norank_d_Bacteria 和未分类_p_Proteobacteria 分别调节 NO-N 和 ASN。这三个属在介导 NIR 活性和 nosZ/nirK 方面起着关键作用。对于 nirS-反硝化菌，Paracoccus 和 Pseudomonas 分别介导 NH-N 和 AAN，它们是调节 NO-N、ASN 和 NIR 活性的重要属。此外，nirK-反硝化菌是反硝化的主要贡献者。总体而言，功能反硝化菌可能同时参与多种 N 转化过程。
