Ecophysiologie d’une bactérie diazotrophe non cyanobactérienne

@article{doi:10.1128/spectrum.04091-23,

title = {Development and utilization of new O_{2}-independent bioreporters},

author = {Eva Agranier and Pauline Crétin and Aurélie Joublin-Delavat and Léa Veillard and Katia Touahri and François Delavat},

url = {https://journals.asm.org/doi/abs/10.1128/spectrum.04091-23

hal-04505221v1 },

doi = {10.1128/spectrum.04091-23},

year  = {2024},

date = {2024-03-05},

urldate = {2024-03-05},

journal = {Microbiology Spectrum},

volume = {0},

number = {0},

pages = {e04091-23},

abstract = {Fluorescent proteins are used for decades, and have allowed major discoveries in biology in a wide variety of fields, and are used in environmental as well as clinical contexts. Green fluorescent protein (GFP) and all its derivatives share a common feature: they rely on the presence of dioxygen (O2) for protein maturation and fluorescence. This dependency precludes their use in anoxic environments. Here, we constructed a series of genetic circuits allowing production of KOFP-7, an O2-independant flavin-binding fluorescent protein. We demonstrated that Escherichia coli cells producing KOFP-7 are fluorescent, both at the population and single-cell levels. Importantly, we showed that, unlike cells producing GFP, cells producing KOFP-7 are fluorescent in anoxia. Finally, we demonstrated that Vibrio diazotrophicus NS1, a facultative anaerobe, is fluorescent in the absence of O2 when KOFP-7 is produced. Altogether, the development of new genetic circuits allowing O2-independent fluorescence will open new perspective to study anaerobic processes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{joublindelavat_genetic_2022,

title = {Genetic and physiological insights into the diazotrophic activity of a non-cyanobacterial marine diazotroph},

author = {Aurélie Joublin-Delavat and Katia Touahri and Pauline Crétin and Amandine Morot and Sophie Rodrigues and Bruno Jesus and Florian Trigodet and François Delavat},

url = {https://onlinelibrary.wiley.com/doi/10.1111/1462-2920.16261

hal-03993957v1 },

doi = {10.1111/1462-2920.16261},

issn = {1462-2912, 1462-2920},

year  = {2022},

date = {2022-12-01},

urldate = {2022-12-01},

journal = {Environmental Microbiology},

volume = {24},

number = {12},

pages = {6510--6523},

abstract = {Nitrogen (N2) fixation, or diazotrophy, supports a large part of primary production in oceans. Culture-independent approaches highlighted the presence in abundance of marine non-cyanobacterial diazotrophs (NCD), but their ecophysiology remains elusive, mostly because of the low number of isolated NCD and because of the lack of available genetic tools for these isolates. Here, a dual genetic and functional approach allowed unveiling the ecophysiology of a marine NCD affiliated to the species Vibrio diazotrophicus. Physiological characterization of the first marine NCD mutant obtained so far was performed using a soft-gellan assay, demonstrating that a ΔnifH mutant is not able to grow in nitrogen-free media. Furthermore, we demonstrated that V. diazotrophicus produces a thick biofilm under diazotrophic conditions, suggesting biofilm production as an adaptive response of this NCD to cope with the inhibition of nitrogen fixation by molecular oxygen. Finally, the genomic signature of V. diazotrophicus is essentially absent from metagenomic data of Tara Ocean expeditions, despite having been isolated from various marine environments. We think that the genetically tractable V. diazotrophicus strain used in this study may serve as an ideal model to study the ecophysiology of these overlooked procaryotic group.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}