MICROBIAL DYNAMICS GOVERNING CARBON STORAGE IN THE COVER CROP ROOT ZONE

The goals of this project are to (1)build a foundational understanding of microbe-mediated soil organic matter (SOM) cyclingin two agronomically important cover cropsand(2) facilitate essential training and professional developmentthat will enable the PD to achieve career independence in an academic field.Objective 1 (Goal 1):Characterize microbe-plant interactions that lead to contrasting SOM outcomes within cover crop rhizospheres.We will quantitatively measure microbial growth dynamics in response to root growth and apply network analysis to characterize microbe-plant-SOM interactions.Objective 2 (Goal 1):Evaluate whether rhizosphere enrichment of phenolic acid-degrading bacteria alters net SOM formation. We will monitor oxidative enzyme activity and use stable isotopes to track the incorporation of root carbon into phenolic acid-degrading bacteria and SOM fractions. This work will determine the relevance of phenolic acid-dependent priming of SOM in the presence of living cover crop roots.Objective 3 (Goal 1):Create synthetic communities of bacterial strains isolated from cover crop rhizospheres to test the hypothesis that microbial community composition and phenolic acid catabolism drive SOM formation. We will employ knowledge from Objs. 1 & 2 to select isolates based on their ability to degrade phenolic acids and evaluate their contribution to SOM stabilization when applied as a cover crop inoculant.Objective 1 (Goal 2): Project results will be communicated by publishing at least two first-author articles in high-impact journals such asPNAS,Nature, orGlobal Change Biology.Objective 2 (Goal 2):The PD will learn and deploy new skills in microbiology, bioinformatics, and stable isotope probing, laying the foundation for an independent research program after the fellowship period.Objective 3 (Goal 2):PD will attend at least one national scientific conference to communicate project results and identify future collaborators or employers.Objective 4 (Goal 2):PD will hone their teaching skills by guest-lecturing in at least one undergraduate-level course and generate original teaching material for at least three classes.