CRISPR/Cas9-germline editing of <i>Biomphalaria glabrata</i> : A breakthrough in genetic modification of snails that transmit schistosomiasis

Human schistosomiasis remains one of the most devastating parasitic diseases worldwide, and the development of genetically modified vector snails has long been a goal in the field. Here, we report the successful creation of genetically modified <i>Biomphalaria glabrata</i>, an important intermediate host, using CRISPR/Cas9 gene editing. We targeted the <i>fibrinogen-related protein 3.1</i> (<i>FREP3.1</i>) gene, confirmed stable germline transmission of the mutated gene, and established two different homozygous <i>FREP3.1</i>-edited lines. Disruption of the <i>FREP 3.1</i> gene did not alter snail susceptibility to <i>Schistosoma mansoni</i> infection, possibly due to a limited role of <i>FREP3.1</i> in resistance or to functional redundancy and/or compensatory expression within the highly diverse <i>FREP</i> gene family. Our study demonstrates successful germline editing, effective ex ovo culture of decapsulated embryos, and the generation of viable, genetically modified <i>B. glabrata</i> snails, thereby establishing a foundation for future genetic strategies to control schistosomiasis.