The apicoplast is important for the viability and persistence of 1 Toxoplasma gondii bradyzoites 2

16 Toxoplasma gondii is responsible for toxoplasmosis, a disease that can be serious when contracted 17 during pregnancy, but can also be a threat for immunocompromised individuals. Acute infection is 18 associated with the tachyzoite form that spreads rapidly within the host. However, under stress 19 conditions, some parasites can differentiate into cyst-forming bradyzoites, residing mainly in the 20 central nervous system, retina and muscle. Because this latent form of the parasite is resistant to 21 all currently available treatments, and is central to persistence and transmission of the parasite, 22 new specific therapeutic strategies targeting this developmental stage need to be discovered. 23 T. gondii contains a plastid of endosymbiotic origin called the apicoplast, which is an appealing 24 drug target because it is essential for tachyzoite viability and contains several key metabolic 25 pathways that are largely absent from the mammalian host. Its function in bradyzoites, however, is 26 unknown. Our objective was thus to study the contribution of the apicoplast to the viability and 27 persistence of bradyzoites during chronic toxoplasmosis.