Rapid response of nitrogen cycling gene transcription to labile carbon amendments in a soil microbial community

Abstract

Episodic inputs of labile carbon (C) to soil can rapidly stimulate nitrogen (N) immobilization by soil microorganisms. However, the transcriptional patterns that underlie this process remain unclear. In order to better understand the regulation of N cycling in soil microbial communities, we conducted a 48 h laboratory incubation with an agricultural soil where we stimulated the uptake of inorganic N by amending the soil with glucose. We analyzed the metagenome and metatranscriptome of the microbial communities at four timepoints that corresponded with changes in N availability. The relative abundances of genes remained largely unchanged throughout the incubation. In contrast, glucose addition rapidly increased transcription of genes encoding for ammonium and nitrate transporters, enzymes responsible for N assimilation into biomass, and genes associated with the N regulatory network. This upregulation coincided with an increase in transcripts associated with glucose breakdown and oxoglutarate production, demonstrating a connection between C and N metabolism. When concentrations of ammonium were low, we observed a transient upregulation of genes associated with the nitrogen fixing enzyme nitrogenase. Transcripts for nitrification and denitrification were downregulated throughout the incubation, suggesting that dissimilatory transformations of N may be suppressed in response to labile C inputs in these soils. These results demonstrate that soil microbial communities can respond rapidly to changes in C availability by drastically altering the transcription of N cycling genes.

An exploration of mechanism of high quality and yield of Gastrodia elata Bl. f. glauca by the isolation, identification and evaluation of Armillaria

“…The decreased copy number of functional genes of transcription, folding, classification and degradation, replication and repair and translation and so on may be correlated with the improvement in disease resistance in G. elata Bl. f. glauca by JMG [65][66][67]. These results indicated that JMG improves soil microbial metabolic functions of G. elata Bl.…”

Inherent tendency of Synechococcus and heterotrophic bacteria for mutualism on long-term coexistence despite environmental interference

“…5, A and B, and 9C). Genes encoding organic nitrogen mineralization ( gudB , gdh , gdhD , and GLUD1_2 ) are also known to carry out the same reaction in reverse order, i.e., generating amino acid glutamate from NH 4 + ( 39 ), therefore confounding its influence on bioavailable N generation. At the same time, the significant up-regulation of DNRA in the P-VI phase also cannot be ignored.…”