2017 ASHS Annual Conference

Microbial dynamics and plant-microbe interactions in the rhizosphere have long been topics of interest in horticulture, due to their influence on plant disease and role in nutrient acquisition. Information regarding plant rhizodeposits that impact rhizobiome and chemistry is limited to date and typically focuses on a few particular pathways. Metabolic profiling is a technique which enables both the characterization of metabolites produced by plant roots as well as indirect assessment of microbial activity. This technique evaluates levels of small molecules from multiple pathways simultaneously using methods such as gas-chromatograph-mass spectrometry, liquid-chromatography-mass spectrometry, or nuclear magnetic resonance spectroscopy. Metabolic profiling has almost limitless potential with regard to improved understanding of horticulturally regulated aspects of the rhizosphere, including precision phenotyping of soil environments, rhizosphere microbial engineering, new chemistries for disease control, and plant breeding efforts. For this workshop, both conceptual as well as methodology considerations for the application of metabolic profiling to the rhizosphere will be discussed. To provide a knowledge basis and a conceptual framework, forms of rhizodeposition and functional attributes of rhizodeposits, as well as metabolic profiling of rhizodeposits, will be discussed. Second, the merits and challenges of both “targeted” vs “untargeted” metabolic profiling, and the metabolic profiling of axenic plant rhizodeposition vs the “holobiont”, along with the implications for interpretation in each with be examined. Options for performing metabolic profiling research where equipment availability is limited will be considered.