Disentangling the rhizosphere effect on nitrate reducers and denitrifiers: insight into the role of root exudates
Article first published online: 3 APR 2008
Journal compilation © 2008 Society for Applied Microbiology and Blackwell Publishing Ltd. No claim to original French government works
Volume 10, Issue 11, pages 3082–3092, November 2008
How to Cite
Henry, S., Texier, S., Hallet, S., Bru, D., Dambreville, C., Chèneby, D., Bizouard, F., Germon, J. C. and Philippot, L. (2008), Disentangling the rhizosphere effect on nitrate reducers and denitrifiers: insight into the role of root exudates. Environmental Microbiology, 10: 3082–3092. doi: 10.1111/j.1462-2920.2008.01599.x
- Issue published online: 30 SEP 2008
- Article first published online: 3 APR 2008
- Received 31 October, 2007; accepted 6 February, 2008.
To determine to which extent root-derived carbon contributes to the effects of plants on nitrate reducers and denitrifiers, four solutions containing different proportions of sugar, organic acids and amino acids mimicking maize root exudates were added daily to soil microcosms at a concentration of 150 μg C g−1 of soil. Water-amended soils were used as controls. After 1 month, the size and structure of the nitrate reducer and denitrifier communities were analysed using the narG and napA, and the nirK, nirS and nosZ genes as molecular markers respectively. Addition of artificial root exudates (ARE) did not strongly affect the structure or the density of nitrate reducer and denitrifier communities whereas potential nitrate reductase and denitrification activities were stimulated by the addition of root exudates. An effect of ARE composition was also observed on N2O production with an N2O:(N2O + N2) ratio of 0.3 in microcosms amended with ARE containing 80% of sugar and of 1 in microcosms amended with ARE containing 40% of sugar. Our study indicated that ARE stimulated nitrate reduction or denitrification activity with increases in the range of those observed with the whole plant. Furthermore, we demonstrated that the composition of the ARE affected the nature of the end-product of denitrification and could thus have a putative impact on greenhouse gas emissions.