A simple assay for quantification of plant-associative bacterial nitrogen fixation

Preprint

Accurate quantification of plant-associative bacterial nitrogen (N) fixation is crucial for selection and development of elite diazotrophic inoculants that could be used to supply cereal crops with nitrogen in a sustainable manner. Because a low oxygen environment that may not be conducive to plant growth is essential for optimal stability and function of the N-fixing catalyst nitrogenase, quantification of N fixation is routinely carried out on “free-living” bacteria grown in the absence of a host plant. Such experiments may not divulge the true extent of N fixation occurring in the rhizosphere where the availability and forms of nutrients such as carbon and N, which are key regulators of N fixation, may vary widely. Here, we present a modified in planta acetylene reduction assay, utilising the model cereal barley as a host, to quantify associative N fixation by diazotrophic bacteria. The assay is rapid, highly reproducible, applicable to a broad range of diazotrophs, and can be performed with simple equipment commonly found in most laboratories that investigate plant-microbe interactions.

Authors: Haskett, TL; Poole, PS

• Publication status: Published
• Peer review status: Not peer reviewed
• Preprint server: bioRxiv
• Publication date: 2021-04-01
• DOI: 10.1101/2021.03.31.437999
• EISSN: 2692-8205
• Language: English