Agrobacterium fabrum C58 involved nitrate reductase NapA and antisense RNA NorR to denitrify. Issue 1 (18th November 2020)

• Record Type: Journal Article
• Authors: Lecomte, Solène; Nesme, Xavier; Franzino, Théophile; Villard, Camille; Pivard, Mariane; Vial, Ludovic; Doré, Jeanne; Hommais, Florence; Haichar, Feth el Zahar
• Is Part Of: FEMS microbiology ecology. Volume 97:Issue 1(2021)
• Publication Date: 2020-11-18
• Subjects: denitrification -- NapA -- nitrate reductase -- fitness -- root colonization -- small RNA; Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1093/femsec/fiaa233
• Languages: English
• ISSNs: 0168-6496

Abstract

ABSTRACT: Agrobacterium fabrum C58 is a plant-associated bacterium that is able to denitrify under anoxic conditions. The cluster of denitrification genes harbored by this strain has been well characterized. It includes nir and nor operons encoding nitrite and nitric oxide reductases, respectively. However, the reductase involved in nitrate reduction has not yet been studied and little information is available on denitrification regulators in A. fabrum C58. In this study, we aimed to (i) characterize the nitrate reductase, (ii) determine its role in A. fabrum C58 fitness and root colonization and (ii) reveal the contribution of small RNA on denitrification regulation. By constructing a mutant strain defective for napA, we demonstrated that the reduction of nitrate to nitrite was catalyzed by the periplasmic nitrate reductase, NapA. We evidenced a positive role of NapA in A. fabrum C58 fitness and suggested that A. fabrum C58 is able to use components exuded by plant roots to respire anaerobically. Here, we showed that NorR small RNA increased the level of norCBQ mRNA and a decrease of NorR is correlated with a decrease in N2 O emission. Together, our results underscore the importance of understanding the denitrification pathway at the strain level in order to develop strategies to mitigate N2 O production at the microbial community level. Abstract : The nitrate reductase NapA is involved in Agrobacterium fabrum C58 fitness and the non conding RNA NorR in involved in denitrification regulation.