In vivo imaging and quantification of carbon tracer dynamics in nodulated root systems of pea plants

Abstract

Legumes associate with root colonizing rhizobia that provide fixed nitrogen to its plant host in exchange for recently fixed carbon. There is a lack in understanding how individual plants modulate carbon allocation to a nodulated root system as a dynamic response to abiotic stimuli. One reason is that most approaches are based on destructive sampling, making quantification of localized carbon allocation dynamics in the root system difficult. We established an experimental workflow for routinely using non-invasive Positron Emission Tomography (PET) to follow the allocation of leaf-supplied 11 C tracer towards individual nodules in a three-dimensional (3D) root system of pea ( Pisum sativum ). Nitrate was used for triggering the shutdown of biological nitrogen fixation (BNF) expected to rapidly affect carbon allocation dynamics in the root-nodule system. This nitrate treatment lead to a reduction of 11 C tracer allocation to nodules by 40% – 47% in 5 treated plants while the variation in control plants was less than 11%. The established experimental pipeline enabled for the first time that several plants could consistently be labelled and measured using 11 C tracer in a PET approach to quantify C-allocation to individual nodules following a BNF shutdown. This demonstrates the strength of using 11 C tracers in a PET approach for non-invasive quantification of dynamic carbon allocation in several growing plants over several days. A major advantage of the approach is the possibility to investigate carbon dynamics in small regions of interest in a 3D system such as nodules in comparison to whole plant development. One sentence summary Positron Emission Tomography for quantification of carbon allocation dynamics in individual nodules within a 3D root system revealed strong effect of nitrate on carbon allocation.

Plant phenotyping relevance

PETを用いた非侵襲的な根粒別炭素配分の3D定量ワークフローと測定パイプラインの確立が中心であり、植物の生理状態を抽出する方法研究に該当する。

Code and data availability

The supplied blocks describe an 11C-PET/MRI carbon allocation study in pea nodules, including custom MeVisLab analysis tools and supplemental figures/tables, but contain no public data deposit, no author code repository URL, and no availability statement for datasets, images, or software. Supplemental data is only said

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