Transcriptomic Profiling of GRA47 Deletion in Toxoplasma gondii Reveals Transcriptional Reprogramming of Stress Adaptation and Metabolic Compensation.

Dense granule protein 47 (GRA47) of Toxoplasma gondii, which localizes to the parasitophorous vacuole membrane (PVM) and the parasitophorous vacuole (PV), is critical for PVM integrity, nutrient permeability, and parasite virulence. However, the global transcriptional response to GRA47 loss remains unexplored. High-throughput RNA sequencing was performed to compare transcriptomic profiles of a GRA47 knockout strain (RHΔgra47) and its parental wild-type RH strain. Differentially expressed genes (DEGs) were identified and analyzed by Gene Ontology (GO) and KEGG enrichment, with selected DEGs validated by reverse transcription quantitative real-time PCR (RT-qPCR). A total of 285 DEGs were identified, comprising 218 upregulated and 67 downregulated genes. Upregulated DEGs were enriched in autophagy, mitophagy, ribosome biogenesis, and GPI anchor biosynthesis pathways, along with nutrient starvation response terms, which may suggest potential roles for the activation of stress response and compensatory metabolic programs. Downregulated DEGs were enriched in host cell entry, rhoptry components, membrane-related terms, and the Hedgehog signaling pathway, a pattern that could suggest a possible association with resource allocation strategy. This first transcriptomic analysis of GRA47 loss in T. gondii identifies transcriptional changes that point to a possible resource allocation strategy prioritizing parasite survival over proliferation and offers a foundational resource for investigating compensatory mechanisms and developing novel intervention strategies. This study reports transcriptional changes only; further experiments are needed to confirm protein-level effects and biological function.