TY - JOUR T1 - The calcifying interface in a stony coral’s primary polyp: An interplay between seawater and an extracellular calcifying space JF - bioRxiv DO - 10.1101/2021.06.09.447817 SP - 2021.06.09.447817 AU - Gal Mor Khalifa AU - Shani Levy AU - Tali Mass Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/06/10/2021.06.09.447817.abstract N2 - Stony coral exoskeletons build the foundation to the most biologically diverse yet fragile marine ecosystems on earth, coral reefs. Understanding corals biomineralization mechanisms is therefore crucial for coral reef management and for using coral skeletons in geochemical studies. In this study, we combine in-vivo and cryo-electron microscopy with single-cell RNA-seq data to gain novel insights into the calcifying micro-environment that facilitates biomineralization in primary polyps of the stony coral Stylophora pistillata. We show an intimate involvement of seawater in this micro-environment. We further document increased tissue permeability and a highly dispersed cell packing in the tissue secreting the coral skeleton (i.e. calicoblastic). We also observe an extensive filopodial network containing carbon-rich vesicles extruding from some of the calicoblastic cells. Single-cell RNA-Seq data interrogation shows that calicoblastic cells express genes involved in filopodia and vesicle structure and function. These observations provide a new conceptual framework for resolving stony corals biomineralization processes.Competing Interest StatementThe authors have declared no competing interest. ER -