Nitrification inhibitors effectively target N₂O‐producing Nitrosospira spp. in tropical soil

Abstract

SummaryThe nitrification inhibitors (NIs) 3,4‐dimethylpyrazole (DMPP) and dicyandiamide (DCD) can effectively reduce N2O emissions; however, which species are targeted and the effect of these NIs on the microbial nitrifier community is still unclear. Here, we identified the ammonia oxidizing bacteria (AOB) species linked to N2O emissions and evaluated the effects of urea and urea with DCD and DMPP on the nitrifying community in a 258 day field experiment under sugarcane. Using an amoA AOB amplicon sequencing approach and mining a previous dataset of 16S rRNA sequences, we characterized the most likely N2O‐producing AOB as a Nitrosospira spp. and identified Nitrosospira (AOB), Nitrososphaera (archaeal ammonia oxidizer) and Nitrospira (nitrite‐oxidizer) as the most abundant, present nitrifiers. The fertilizer treatments had no effect on the alpha and beta diversities of the AOB communities. Interestingly, we found three clusters of co‐varying variables with nitrifier operational taxonomic units (OTUs): the N2O‐producing AOB Nitrosospira with N2O, NO3 −, NH4 +, water‐filled pore space (WFPS) and pH; AOA Nitrososphaera with NO3 −, NH4 + and pH; and AOA Nitrososphaera and NOB Nitrospira with NH4 +, which suggests different drivers. These results support the co‐occurrence of non‐N2O‐producing Nitrososphaera and Nitrospira in the unfertilized soils and the promotion of N2O‐producing Nitrosospira under urea fertilization. Further, we suggest that DMPP is a more effective NI than DCD in tropical soil under sugarcane.

Filling in the Gaps in Metformin Biodegradation: a New Enzyme and a Metabolic Pathway for Guanylurea

“…While microbial metabolism of metformin is considered to be the major source of guanylurea, it can also derive from other anthropogenic and natural sources. Guanylurea may also accumulate from the microbial degradation of cyanoguanidine (dicyanodiamide), a common fertilizer additive ( 21 , 22 ). Derivatives of guanylurea are utilized in the manufacture of flame retardants as well as propellants for energetic compounds and munitions ( 23 , 24 ).…”

Microorganisms as bio‐filters to mitigate greenhouse gas emissions from high‐altitude permafrost revealed by nanopore‐based metagenomics

“…We could not detect active ammonia‐oxidizing archaea (AOA) in permafrost and such AOB‐dominated nitrogen metabolism was also observed in research in cold environments like high‐altitude lakes [52] and permafrost in northeast Siberia [53]. Nitrosospira is a typical AOB and lives in various environments [54,55]. Although typical Nitrosospira like those in domestic wastewater treatment plants prefers warmer growing environment (25°C to 30°C) [56], a recent study had found certain species of Nitrosospira could adapt and enrich in the cold environment [53], and our results consolidated this finding.…”

Efeitos da conversão pastagem-canavial e da intensificação do sistema de pastagem na microbiota do solo associada ao ciclo do nitrogênio

“…Considerando que os microrganismos do solo são os principais agentes das transformações do N na interface solo-planta-atmosfera, compreender a ecologia dos microrganismos responsáveis pelos principais processos relacionados à perda do N no sistema é de grande importância para o avanço do uso eficiente do N na agricultura (CASSMAN et al, 2019;RIGOTTO et al, 2020).…”

“…Os microrganismos do solo e as interações que ocorrem entre si e com os compartimentos planta e atmosfera atuam na ciclagem do carbono, fósforo, nitrogênio, entre outros elementos, que, quando em equilíbrio ecológico, favorecem a fertilidade do solo e a sustentabilidade dos sistemas agrícolas SIQUEIRA, 2006). Tendo em vista a importância do N para os sistemas naturais e agrícolas, o conhecimento da composição da comunidade microbiana e dos processos que regulam a distribuição das formas de N no solo tem potencial para subsidiar ações mitigadoras sobre as perdas deste nutriente no ambiente (CASSMAN et al, 2019). A nova forma de explorar abundância e composição microbianas por meio de sequências de DNA esclarece como as comunidades microbianas atuam no regulamento dos diversos processos biogeoquímicos e como alterações nessas comunidades afetam as atividades em que estão envolvidas (NELSON; MARTINY; MARTINY, 2016;WANG et al, 2018).…”

“…Uma vez que a presença de comunidades associadas à nitrificação implica na emissão de N2O quando em condições favoráveis de nitrificação, tal como sob o aumento do conteúdo de N pela aplicação de fertilizantes (DI et al, 2010;MEINHARDT et al, 2018;PROSSER et al, 2020), mesmo que correlações entre o gene amoA, de bactérias e arqueias e as concentrações de amônio no solo não sejam observadas (CASSMAN et al, 2019).…”