Diel changes in the expression of a marker gene and candidate genes for intracellular amorphous CaCO3 biomineralization in *Microcystis*use asterix (*) to get italics

Apolline Bruley, Juliette Gaëtan, Muriel Gugger, Claire Pancrace, Maxime Millet, Geoffroy Gaschignard, Manuela Dezi, Jean-François Humbert, Julie Leloup, Fériel Skouri-Panet, Isabelle Callebaut, Karim Benzerara, Elodie DupratPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"

2024

<p>Phylogenetically diverse cyanobacteria biomineralize intracellular amorphous calcium carbonate (iACC) inclusions. This includes several genotypes of the Microcystis genus, a potentially toxic, bloom-forming cyanobacterium found worldwide in freshwater ecosystems. While we ignore the biological function of iACC and the molecular mechanisms driving their formation, this process may impact local geochemical cycles and/or be used for bioremediation strategies. Recently, a marker gene of this biomineralization pathway, named ccyA, was discovered. However, the function of the calcyanin protein encoded by ccyA remains unknown. Here, based on an RNA-Seq approach, we assess the expression of the ccyA gene in Microcystis aeruginosa PCC 7806 during a 24 h day/night cycle. The ccyA gene shows a clear day/night expression pattern with maximum transcript abundances during the second half of the night. This is consistent with the assumption that iACC biomineralization is related with photosynthesis and may therefore follow a day/night cycle as well. Moreover, several genes directly co-localized upstream and downstream of ccyA, on the same DNA strand show a similar expression pattern, including a cax gene encoding a calcium/proton exchanger and a gene encoding a protein with a domain also present in the N-terminal region of calcyanins in many iACC-forming cyanobacteria. This suggests that they all could be part of an operon, and may play a concerted role in iACC formation. Last, several other genes involved in carbon concentrating mechanisms and calcium transport show an expression pattern similar to that of ccyA. Overall, this study provides a list of candidate genes that may be involved in the biomineralization of iACC by cyanobacteria and whose role could be, in the future, analyzed by biochemistry and genetics approaches.</p>

https://www.biorxiv.org/content/10.1101/2024.07.07.602159v3.supplementary-materialYou should fill this box only if you chose 'All or part of the results presented in this preprint are based on data'. URL must start with http:// or https://

https://github.com/PF2-pasteur-fr/clean_ngsYou should fill this box only if you chose 'Scripts were used to obtain or analyze the results'. URL must start with http:// or https://

Microcystis; cyanobacteria; calcium; biomineralization; gene expression

NonePlease indicate the methods that may require specialised expertise during the peer review process (use a comma to separate various required expertises).

Microbial biogeochemistry, Microbial ecology and environmental microbiology, Microbial physiology, ecophysiology and metabolism

Gregory Dick gdick@umich.edu, Marianna Patrauchan m.patrauchan@okstate.edu, Frédéric Marin frederic.marin@u-bourgogne.fr, Clara Chan schan@udel.edu, Muammar Mansor muammar.muammar-bin-mansor@uni-tuebingen.de, Anne Chenuil suggested: Lucie Miché lucie.miche@imbe.fr, Pieter Visscher suggested: Ferran Garcia Pichel, Lucie Miché suggested: Steven Criquet steven.criquet@imbe.fr, Rutger De Wit suggested: Marc Bouvy marc.bouvy@ird.fr

e.g. John Doe john@doe.com

No need for them to be recommenders of PCIMicrobiol. Please do not suggest reviewers for whom there might be a conflict of interest. Reviewers are not allowed to review preprints written by close colleagues (with whom they have published in the last four years, with whom they have received joint funding in the last four years, or with whom they are currently writing a manuscript, or submitting a grant proposal), or by family members, friends, or anyone for whom bias might affect the nature of the review - see the code of conduct

2024-07-11 17:56:28

Rutger De Wit