Competition between plant and bacterial cells at the microscale regulates the dynamics of nitrogen acquisition in wheat (Triticum aestivum)
Article first published online: 12 JUL 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 200, Issue 3, pages 796–807, November 2013
How to Cite
Jones, D. L., Clode, P. L., Kilburn, M. R., Stockdale, E. A. and Murphy, D. V. (2013), Competition between plant and bacterial cells at the microscale regulates the dynamics of nitrogen acquisition in wheat (Triticum aestivum). New Phytologist, 200: 796–807. doi: 10.1111/nph.12405
- Issue published online: 11 OCT 2013
- Article first published online: 12 JUL 2013
- Manuscript Accepted: 9 JUN 2013
- Manuscript Received: 26 APR 2013
- Australian Research Council. Grant Number: FT110100246
- NIH/NIBIB. Grant Number: 5P41 EB001974-10
- amino acids;
- dissolved organic nitrogen;
- nitrogen cycling;
- nutrient uptake;
- rhizosphere architecture
- The ability of plants to compete effectively for nitrogen (N) resources is critical to plant survival. However, controversy surrounds the importance of organic and inorganic sources of N in plant nutrition because of our poor ability to visualize and understand processes happening at the root–microbial–soil interface.
- Using high-resolution nano-scale secondary ion mass spectrometry stable isotope imaging (NanoSIMS-SII), we quantified the fate of 15N over both space and time within the rhizosphere. We pulse-labelled the soil surrounding wheat (Triticum aestivum) roots with either or 15N-glutamate and traced the movement of 15N over 24 h.
- Imaging revealed that glutamate was rapidly depleted from the rhizosphere and that most 15N was captured by rhizobacteria, leading to very high 15N microbial enrichment. After microbial capture, approximately half of the 15N-glutamate was rapidly mineralized, leading to the excretion of , which became available for plant capture. Roots proved to be poor competitors for 15N-glutamate and took up N mainly as . Spatial mapping of 15N revealed differential patterns of 15N uptake within bacteria and the rapid uptake and redistribution of 15N within roots.
- In conclusion, we demonstrate the rapid cycling and transformation of N at the soil–root interface and that wheat capture of organic N is low in comparison to inorganic N under the conditions tested.