Competition between plant and bacterial cells at the microscale regulates the dynamics of nitrogen acquisition in wheat (Triticum aestivum). Issue 3 (12th July 2013)

• Record Type: Journal Article
• Authors: Jones, David L.; Clode, Peta L.; Kilburn, Matt R.; Stockdale, Elizabeth A.; Murphy, Daniel V.
• Is Part Of: New phytologist. Volume 200:Issue 3(2013)
• Page Start: 796
• Page End: 807
• Publication Date: 2013-07-12
• Subjects: Botany -- Periodicals; 580
• DOI: 10.1111/nph.12405
• Languages: English
• ISSNs: 0028-646X

Abstract

<abstract abstract-type="main" id="nph12405-abs-0001"> <title>Summary</title> <p> <list id="nph12405-list-0001" list-type="bullet"> <list-item> <p>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.</p> </list-item> <list-item> <p>Using high‐resolution nano‐scale secondary ion mass spectrometry stable isotope imaging (NanoSIMS‐SII), we quantified the fate of <sup>15</sup>N over both space and time within the rhizosphere. We pulse‐labelled the soil surrounding wheat (<italic>Triticum aestivum</italic>) roots with either <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3m83k8f1" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:0028646X:media:nph12405:nph12405-math-0004" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>15</mml:mn></mml:mrow></mml:msup><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></alternatives> or <sup>15</sup>N‐glutamate and traced the movement of <sup>15</sup>N over 24 h.</p> </list-item> <list-item> <p>Imaging revealed that glutamate was rapidly depleted from the rhizosphere and that most <sup>15</sup>N was captured by rhizobacteria, leading to very high <sup>15</sup>N microbial enrichment. After microbial capture, approximately half of the <sup>15</sup>N‐glutamate was rapidly mineralized, leading to the excretion of <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3m83k8gk" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:0028646X:media:nph12405:nph12405-math-0005" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></alternatives>, which became available for plant capture. Roots proved to be poor competitors for <sup>15</sup>N‐glutamate and took up N mainly as <alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgg3m83k8cx" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math altimg="urn:x-wiley:0028646X:media:nph12405:nph12405-math-0006" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>15</mml:mn></mml:mrow></mml:msup><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></alternatives>. Spatial mapping of <sup>15</sup>N revealed differential patterns of <sup>15</sup>N uptake within bacteria and the rapid uptake and redistribution of <sup>15</sup>N within roots.</p> </list-item> <list-item> <p>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.</p> </list-item> </list> </p> </abstract>