Biotic Stress/Applied Plant Bio

Abstract

CS-18-2 - Spatially exploring the metabolome of soybean root nodules with high resolution mass spectrometry imaging revealed unexpected complexity in rhizobacteria-legume metabolites

Monday, July 16
3:38 PM - 3:58 PM

Elucidating the metabolic processes within plant systems known to obtain nitrogen through biological nitrogen fixation (BNF) is essential for more sustainable agricultural practices. The symbiotic association between nitrogen-fixing soil bacteria (Rhizobiaceae) and plants of the family Leguminosae (e.g., soybean), which generate specialized organs called root nodules, are one such system of interest. However, little is known about the array of metabolites involved, and their spatial distribution, which influence the rhizobia-legume association. Recently, our group described a method for rapidly profiling the metabolome of intact soybean root nodules, along with its individual biological components, using laser ablation electrospray ionization mass spectrometry (LAESI-MS). This method was also able to provide some spatially resolved metabolic information on the anatomical compartments of the root nodule, where we were able to detect soyasaponins in the epidermis, heme B and jasmonoyl aminocyclopropane carboxylate in the infection zone, and monosaccharides and flavonones in both the outer and inner region, for example. Further exploration of the soybean root nodules with high (spatial and mass) resolution molecular tomography, via matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), revealed unexpected complexity in the soybean nodule metabolism. We found that, while many metabolites exhibited distinct spatial compartmentalization, some metabolites were asymmetrically distributed throughout the nodule (e.g., S-adenosylmethionine). These results establish a more complex metabolic view of plant-bacteria symbiosis (and BNF) within soybean nodules than previously hypothesized. Further, these findings suggest that spatial perspectives in metabolic regulation should be considered to unravel the overall complexity of interacting organisms, like those relating to associations of nitrogen-fixing bacteria with host plants. Note, these MSI tools and more are available for the use by the global research community through the user program of the Environmental Molecular Sciences Laboratory, which is a US Dept. of Energy User Facility.


 

Co-Authors

Dušan Veličković – Pacific Northwest National Laboratory; Beverly Agtuca – University of Missouri, Columbia; Sylwia Stopka – The George Washington University; David Koppenaal – Pacific Northwest National Laboratory; Akos Vertes – The George Washington University; Ljiljana Paša-Tolić – Pacific Northwest National Laboratory; Gary Stacey – University of Missouri, Columbia

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CS-18-2 - Spatially exploring the metabolome of soybean root nodules with high resolution mass spectrometry imaging revealed unexpected complexity in rhizobacteria-legume metabolites



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Send Email for Spatially exploring the metabolome of soybean root nodules with high resolution mass spectrometry imaging revealed unexpected complexity in rhizobacteria-legume metabolites