Location: Potato, Pulse and Small Grains Quality Research
Project Number: 3060-21650-002-073-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2025
End Date: Dec 31, 2026
Objective:
This project aims to improve pulse crop productivity and nitrogen use efficiency by evaluating the nitrogen-fixing performance, yield, and protein content of winter and spring field peas (Pisum sativum) inoculated with stress-tolerant native rhizobia compared to commercial strains. Specifically, (1) Compare the nitrogen fixation efficiency of native and commercial Rhizobium leguminosarum strains in winter and spring peas, (2) Characterize physiological and seasonal differences in nodulation and nitrogen fixation, and (3) Use metagenomic and metatranscriptomic approaches to identify microbial functions and gene expression linked to effective symbiosis.
Approach:
The central goal is to optimize plant-microbe interactions, with a specific emphasis on the need for inoculants tailored to the unique growth patterns of winter peas. The Laboratory component will evaluate nitrogen fixation efficiency in Pisum sativum when inoculated with two previously identified native Rhizobium leguminosarum strains showing broad abiotic stress resilience.
This research is broken into two paired components – field and laboratory. The laboratory experiment will evaluate nitrogen fixation efficiency in Pisum sativum when inoculated with two previously identified native Rhizobium leguminosarum strains showing broad abiotic stress resilience, a native rhizobia consortium (comprised of both native species), and the well-documented Rhizobium leguminosarum strain RL3841 as a control. An uninoculated control with the addition of N will serve as an additional negative control. These treatments will be performed under aseptic (sterile) conditions to ensure that only the inoculated bacterial strains occur, and no other bacteria from soil enter the systems. All plant-rhizobia combinations will be tested prior to the start of the trial to ensure adequate compatibility between species. The field experiment will expand the results of the laboratory experiment by evaluating the nitrogen fixation capacity and functional microbial composition of root nodules in winter and spring peas grown under natural field conditions. Specifically, the experiment will compare six rhizobial inoculant treatments across two spring and two winter pea genotypes, using a combination of physiological measurements and metagenomic sequencing to characterize the microbial function and nitrogen fixation potential at key developmental stages.