Seminar: Exploring the plant microbiome using complementary spatial metabolomics techniques

Dates: June 2, 2017

Special Guest Speaker: Christopher R. Anderton
Environmental Molecular Sciences Laboratory, Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory

  • Exploring the plant microbiome using complementary spatial metabolomics techniques
  • Date: Friday, June 2, 2017
  • Time: 10:00 am - 11:00 am
  • Location: Morgan Conference Room, NLSN

Abstract: Plant microbiomes represent a complex mix of interacting species with diverse physiologies and phylogenetic origins, and the functional outcomes from the exchanges within these systems are critical to biogeochemical cycles. Measuring the molecular interactions that occur within these environments is a major technical challenge. Traditional 'omics' methodologies are typically limited in their ability to provide molecular localization, and thus often disregard the multifaceted chemical exchanges within and between interacting species. Mass spectrometry imaging (MSI) methodologies are increasing being adopted to visualize the transaction of molecules across plant microbiomes. A particular area of strength for many MSI techniques is providing the spatial distribution of metabolites in an in situ fashion. The Environmental Molecular Sciences Laboratory, a U.S. Department of Energy User Facility, houses a suite of MSI tools. Here, I will discuss the use of several of these methods to explore biological nitrogen fixation and associated metabolic processes within a rhizobia-legume symbiosis (Bradyrhizobium japonicum and soybean) and a tripartite system of moss, cyanobacteria, and fungus. While these MSI approaches provided insight into the heterogeneous distribution of analytes within these systems, orthogonal measurements were required for increased levels of confidence in the molecular identifications of the detected species. Accordingly using tandem MS, premass analysis ion mobility separations, and high mass resolution and mass accuracy measurements of the isotopic envelope, we could move beyond providing putative identifications based on accurate measured mass alone to providing higher confidence in the identity and localization of metabolites. We further applied this information to elucidate the active metabolic pathways within the plant microbiomes, which provided a better view of actual metabolism than obtained from proteomics and transcriptiomis alone.