Gessica Vasconcelos, Graduate Student, Vertes Lab, GW Department of Chemistry

The Department of Chemistry Presents:  Gessica Vasconcelos, Graduate Student, Vertes Lab, GW Department of Chemistry

Nitrogen is a critical element used in plant development and the lack of it in soil can limit plant growth and production yields. Legumes, such as Glycine max (soybean), can incorporate nitrogen through biological nitrogen fixation (BNF). This process requires a symbiotic relationship between the plant and bacteria capable of converting nitrogen from air into soluble nitrogen compounds. Soybean attracts such bacteria from the soil (Bradyrhizobium japonicum) into specialized organs called nodules. These nodules are attached to the roots and an exchange of metabolites exists between the plant and the bacteroids in the nodules. In this study, we applied optical fiber-based laser ablation electrospray ionization (f-LAESI) mass spectrometry (MS) to perform a comprehensive analysis of molecular distributions at the root-nodule interface. More specifically, we sought to uncover the distribution of metabolites in the nodule, root, and connective tissue (CT – tissue uniting the nodule to the root). The f-LAESI-MS method  in combination with brightfield and fluorescence microscopy allows the direct analysis of small anatomical features, such as single cells or cell clusters in each area. Direct sampling by a mid-IR laser allows analysis on tissues and cells near their native state, which minimizes artifacts due to metabolite turnover and redistribution.  Fluorescence microscopy guided molecular mapping by f-LAESI-MS revealed metabolite exchange in anatomically distinct tissue regions at the plant root-nodule interface.

Bio

Gessica Vasconcelos received M.S. and Ph.D. degrees in Chemistry from Federal University of Goias in Goiania, Brazil, in 2016 and 2020, respectively. In 2019, she joined the Vertes Lab at GWU. Her current work is focused on investigating the metabolome in plant-symbiont mutualism using high performance mass spectrometry-based techniques under ambient conditions.

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