MMPRNTers were all ready for the annual Fall All Hands meeting at KBS when mother nature hit Sunday night with a huge mid-November snow storm. Treacherous roads caused us to postpone the lightning poster session and prevented our guests from Angela Kent and Wendy Yang’s labs (University of Illinois) from driving up. However, MMPRNT persevered and we were able to continue our schedule as planned on day two. While not able to meet in person, Angela and Wendy each joined virtually to presented their work looking at crop genome influences on microbial community structure and the possible importance of nitrogen mineralization in the N budget of Miscanthus. They were also able to listened in to great talks from MMPRNTers Tayler Ulbrich, Darian Smercina, Lukas Bell-Dereske and Rick White III. Even with the rough start, the meeting was a success and everyone is excited about collaboration opportunities with the Kent and Yang labs. Thanks to everyone who participated!
Led by PhD student Darian Smercina, Optimization of the 15N2 incorporation and acetylene reduction methods for free-living nitrogen fixation was recently published in Plant and Soil. Using both the acetylene reduction assay (ARA) and 15N2 incorporation (15N2) method for measuring nitrogen fixation, Darian assessed the impact of different carbon sources, oxygen concentrations and incubation times on Free-Living Nitrogen Fixation (FLNF) rates. She found that a cocktail of different carbon sources greatly increased fixation as compared to other carbon sources. Highlighting the need for project specific optimization, site played a factor in optimal oxygen concentration, while both the optimal incubation time and oxygen concentration varied by method. This work also reinforces previous concerns with ARA and stresses caution when using the method. Check out the full paper for more info!
Darian Smercina, PhD student in the Tiemann lab, recently published an exciting review titled To Fix or Not To Fix: Controls on Free-Living Nitrogen Fixation in the Rhizosphere. Published in Applied and Environmental Microbiology, the paper explores Free Living Nitrogen Fixation (FLNF) as a form of biological N fixation distinct from symbiotic N fixation that may be harnessed to reduce fertilizer inputs in cropping systems. Specifically, the review outlines the ways that environmental conditions and resource availability may control FLNF for a diverse range of rhizosphere diazotroph taxa and offers methodological recommendations to address knowledge gaps in future FLNF studies. Check out the paper to learn more!