Pulse Brain · Growing Health Evidence Index
Tier 3 — Observational / field trialPeer-reviewed

Biological nitrogen fixation in maize: optimizing nitrogenase expression in a root-associated diazotroph

Sarah E. Bloch, Rosemary Clark, Shayin S. Gottlieb, L. K. Wood, Neal Shah, San-Ming Mak, James G. Lorigan, Jenny Johnson, Austin G. Davis‐Richardson, Lorena Williams, Megan McKellar, Dominic Soriano, Max Petersen, Alana Horton, Olivia Smith, Leslie Wu, Emily Tung, Richard Broglie, Alvin Tamsir, Karsten Temme

Journal of Experimental Botany · 2020

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Summary

This research describes the genetic reprogramming of a plant-associated proteobacterium (Kosakonia sacchari) isolated from corn roots to overcome the ecological problem of reduced nitrogen-fixing capacity under high exogenous nitrogen inputs. By targeting key nodes in the bacterial nitrogen regulatory network, the authors engineered strains that maintain elevated nitrogen fixation activity in the rhizosphere of maize even when chemical fertiliser is present. The engineered strains could potentially be deployed as inoculants to reduce reliance on synthetic nitrogen fertilisers in cereal crop production.

Regional applicability

The study was conducted in the United States and focused on maize, which is not a major UK cereal crop by area. However, the approach to enhancing biological nitrogen fixation in non-legume crops through microbial engineering may have broader relevance to UK arable systems, particularly for improving nitrogen-use efficiency and reducing synthetic fertiliser inputs. Transferability would require field validation in UK soil and climatic conditions.

Key measures

Nitrogenase expression levels; ammonium production in the rhizosphere; nitrogen fixation activity in greenhouse and field conditions with and without exogenous nitrogen inputs

Outcomes reported

The study isolated and genetically modified a strain of Kosakonia sacchari from corn roots to maintain elevated nitrogenase expression and ammonium production even in the presence of exogenous nitrogen fertiliser. Field and greenhouse trials demonstrated that remodeled strains sustained nitrogen fixation activity in fertilised corn systems where wild-type strains were repressed.

Theme
Farming systems, soils & land use
Subject
Soil biology & microbiology
Study type
Research
Study design
Field trial
Source type
Peer-reviewed study
Status
Published
Geography
United States
System type
Arable cereals
DOI
10.1093/jxb/eraa176
Catalogue ID
SNmomgxdf2-b9lqiq

Topic tags

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