I2BC Paris-Saclay

Unlocking Genetic Engineering in the CaCO3 / SrCO3 granule forming Cyanothece PCC 7425

Cyanobacterial biodiversity represents an outstanding reservoir of biological diversity with considerable potential for addressing challenges in diverse fields, ranging from human nutrition and health to sustainable production of energy and environmental bioremediation. Among non-model cyanobacteria, several species, including Gloeomargarita lithophora and Cyanothece PCC 7425 are distinguished by their remarkable ability to form intracellular CaCO3 granules within the cytoplasm (iACC). In addition to accumulating high levels of calcium (Ca), these cyanobacteria can concentrate other alkaline earth elements, including strontium (Sr), barium (Ba), and radium (Ra). This unique capacity makes them promising candidates for a range of biotechnological applications, notably CO2 capture and sequestration, and bioremediation of nuclear effluents. However, the absence of efficient genetic tools for iACC forming cyanobacteria has been a major obstacle to investigating the molecular mechanisms underlying iACC formation. To address this limitation, the Biology and Biotechnology of Cyanobacteria team at I2BC, CEA Saclay, in collaboration with Biomin team from IMPMC Sorbonne University has established a genetic toolbox for Cyanothece PCC 7425 enabling both gene overexpression and CRISPR-Cas-mediated gene inactivation 1. These advances provide, for the first time, a powerful experimental framework to dissect the molecular basis of iACC formation and pave the way toward a deeper understanding of this unique biomineralization process. The team, using CRISPR-Cas12a mediated homologous recombination, generated deletion mutants of genes acting in metabolism and/or response to stresses. Importantly, full chromosome segregation was rapidly achieved making selection of null-mutants very effective in this cyanobacterium. With these tools in hand, the team now aims to elucidate the molecular basis of iACC mechanisms and the formation of CaCO3 / SrCO3 granules.

 

More information: https://link.springer.com/article/10.1007/s00253-026-13959-y

Contact: Soufian Ouchan soufian.ouchane@i2bc.paris-saclay.fr

https://www.i2bc.paris-saclay.fr/equipe-biology-and-biotechnology-of-cyanobacteria/