Biochemical mechanism of phosphorus limitation impairing nitrogen fixation in diazotrophic bacterium Klebsiella variicola W12. Issue 2 (27th May 2022)

• Record Type: Journal Article
• Authors: Zhang, Li‐Mei; Silvano, Eleonora; Rihtman, Branko; Aguilo‐Ferretjans, Maria; Han, Bing; Shi, Wei; Chen, Yin
• Is Part Of: Journal of sustainable agriculture and environment. Volume 1:Issue 2(2022)
• Page Start: 108
• Page End: 117
• Publication Date: 2022-05-27
• Subjects: nitrogen fixation -- N–P coupling -- ornithine lipids -- P deficiency -- proteomics; Sustainable agriculture -- Periodicals; Agriculture -- Environmental aspects -- Periodicals; Agriculture -- Environmental aspects; Alternative agriculture; Sustainable agriculture; Periodicals; 630.2086
• DOI: 10.1002/sae2.12024
• Languages: English
• ISSNs: 2767-035X

Abstract

Abstract: Introduction: Biological nitrogen (N) fixation (BNF) plays a key role in nitrogen supply in agricultural and natural ecosystems. Harnessing BNF can substantially reduce dependence on chemical fertilizer in agroecosystems and hence can contribute to sustainable agriculture. However, a number of field studies have demonstrated that BNF can be largely suppressed in phosphorus (P)‐deficient environments, while the underlying mechanism is not well understood. Materials & Methods: In this study, comparative proteomics and lipidomics analyses were conducted on a diazotrophic bacterium Klebsiella variicola W12 under P‐deficient and P‐replete conditions to gain insight into how P availability affects N fixation. Results: Under P deficiency, N fixation activity of K. variicola W12 was severely repressed. In response to P limitation, the bacterium synthesized P‐free ornithine lipids to replace glycerophospholipids in its membrane to reduce cellular demand for P. Comparative proteomics showed that P limitation resulted in upregulation of the PhoBR two‐component system, a range of organic and inorganic P uptake and transport systems, while nitrogenase and N‐fixation‐related transcriptional regulators NifL and NifA were downregulated. Conclusion: These results revealed lipid renovation as an adaptation strategy for N2 ‐fixing microbes to survive under P stress and provided biochemical evidence on how P availability regulates BNF. A conceptual model of N–P coupling at the microbial metabolism level is therefore proposed. Our study provides a simple yet plausible explanation of how P deficiency suppresses BNF observed in the field and highlights the importance of regulating P availability to maximize the potential of BNF in agroecosystems for agriculture sustainable production.