ARS culture collection microbial strains for nitrogen-fixing corn and soybean inoculants
The USDA-ARS Culture Collection houses 98,000 microbial isolates, including over 3,000 from corn and soybean. This offering seeks to identify and characterize fungal and bacterial strains suitable as chassis organisms for developing nitrogen-fixing symbionts and microbial inoculants for these major crops.
Overview
The USDA-ARS Culture Collection is one of the largest publicly maintained microbial repositories in the United States, housing approximately 98,000 isolates of fungi and bacteria. More than 3,000 of these strains were originally isolated from corn or soybean, collected from leaves, roots, seeds, rhizosphere, or seed surfaces. This offering provides a structured pathway to identify, retrieve, and characterize strains from this collection that show promise as chassis organisms for developing nitrogen-fixing symbionts or microbial inoculants for corn and soybean. By tapping into this diverse genetic resource, partners can accelerate the development of sustainable biological nitrogen-fixation solutions that reduce dependence on synthetic fertilizers.
Technical specifications
The ARS Culture Collection contains strains across genera relevant to nitrogen fixation, plant colonization, and synthetic biology, including:
- Known nitrogen fixers: Bradyrhizobium, Rhizobium
- Endophytic and epiphytic colonizers: Aspergillus, Bullera, Fusarium, Paecilomyces, Talaromyces
- Synthetic biology workhorses: Saccharomyces, Aureobasidium, Candida, Hyphopichia, Kazachstania, Pichia
- Root and rhizosphere isolates: Micromonospora, Paenibacillus, Streptomyces, Trichoderma
- Corn seed isolates: Bacillus, Pseudomonas, Sarocladium
Historically, strains from this collection have enabled major biotechnological advances, including commercial production of penicillin, riboflavin, xanthan gum, dextran blood extender, and fermentation of pentose sugars from biomass to fuel alcohol. The proposed work involves a thorough database analysis of all 98,000 strains, identification of candidates matching ideal chassis criteria, retrieval and culturing of selected strains, and shipment to the partner for further assessment and characterization.
Technology readiness level
This is a TRL 2–3 (concept and proof-of-concept stage) offering. The microbial strains themselves are established and preserved biological resources with documented histories of successful biotechnological application. The novel step is the systematic screening and characterization of these strains specifically for use as nitrogen-fixing chassis in corn and soybean. The proposed validation effort is estimated to take approximately one year and requires funding for key personnel to conduct database searches, identify and ship candidate strains, and perform additional characterization analyses. The project is positioned as a foundational discovery phase that will generate candidate strains ready for downstream development by the partner.
About USDA
USDA is a U.S. federal executive department with an applied R&D enterprise delivered through a nationwide network of laboratories, field stations, and specialized repositories. Facilities include pilot‑scale processing lines and testbeds at co‑located university sites and research farms, enabling real‑world evaluation and scale‑up with USDA scientists. USDA engages industry through CRADAs, material transfers, cooperative field trials, and works with the Cooperative Extension System to speed adoption. Research is primarily supported by federal appropriations, with additional interagency collaborations and competitively funded programs. A dedicated tech transfer office manages IP and licensing and streamlines public‑private agreements.
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