Convergent evolution of metabolic regulation governs redox adaptation in Toxoplasma

Apicomplexan parasites experience these stresses during intracellular growth in host cells, yet lack known regulators of metabolic adaptation. We screened the apicomplexan Toxoplasma gondii to identify genes that support parasite fitness during crowding.

NAD(P)+ biosynthesis was required at high parasite density along with several parasite-specific factors, including an RNA-binding protein named T. gondii Parasite Response to Oxidation (TgPRO). TgPRO loss elevated reactive oxygen species under ambient conditions, which was rescued by growth at low oxygen. TgPRO regulates expression of specific transcripts involved in carbon metabolism and iron-sulfur cluster assembly.