New Transcriptome Time Course Maps Blood Stage Development in Plasmodium knowlesi

A newly established transcriptome time course provides the first detailed view of the intraerythrocytic developmental cycle for the zoonotic malaria parasite Plasmodium knowlesi line A1-H.1 cultured in human normocytes. Conducted by researchers Katlijn De Meulenaere, Dalia Díaz-Delgado, Pieter Monsieurs, Erin Sauve, Alfred Cortés, Ellen Knuepfer, and Anna Rosanas-Urgell, the study investigates a parasite closely related to Plasmodium vivax, which represents the second leading cause of human malaria. Because the P. knowlesi line A1-H.1 can be reliably maintained in human erythrocytes, it serves as an invaluable experimental model system for studying P. vivax biology.

To profile gene activity across parasite development, the investigators performed bulk RNA-sequencing across five distinct stages of the intraerythrocytic developmental cycle using tightly synchronised parasite cultures. This experimental approach captured the dynamic transcriptional program of P. knowlesi A1-H.1 as it progresses through human normocytes during asexual replication. The resulting time course dataset provides an essential reference transcriptome framework for the parasite line and establishes a robust empirical foundation for comparative analyses across different Plasmodium species.

The sequencing data enabled the identification of constitutively expressed genes alongside stage-specific transcriptional biomarkers across the different developmental stages. In addition to defining these individual stage-specific biomarkers, the bulk RNA-sequencing measurements allowed researchers to examine the temporal expression patterns of multigene families during the asexual blood cycle.

Comparative analysis with Plasmodium vivax orthologues revealed strong genome-wide conservation of temporal gene expression throughout the intraerythrocytic developmental cycle. Detailed evaluation of invasion-associated genes and ApiAP2 transcription factors identified specific genes displaying conserved temporal expression patterns between both species.

To support ongoing comparative analyses, the research team developed an open-access interactive webtool (https://interactive.itg.be/app/pk-orthologue-expression-viewer) that visualises orthologue expression across Plasmodium knowlesi, Plasmodium vivax, and Plasmodium falciparum across the intraerythrocytic developmental cycle. This digital resource facilitates the rapid identification of candidate genes exhibiting conserved temporal expression, thereby streamlining future functional studies in which P. knowlesi A1-H.1 serves as a practical model for comparative Plasmodium biology and P. vivax research.

Subject of Research: Transcriptome time course of Plasmodium knowlesi intraerythrocytic development

Article Title: A Plasmodium knowlesi A1-H.1 transcriptome time course focusing on the late asexual blood stages

Article References: De Meulenaere, K., Díaz-Delgado, D., Monsieurs, P., Sauve, E., Cortés, A., Knuepfer, E., & Rosanas-Urgell, A. (2026). A Plasmodium knowlesi A1-H.1 transcriptome time course focusing on the late asexual blood stages. PLOS Pathogens, 22(11), e1014727. https://doi.org/10.1371/journal.ppat.1014727

Image Credits: AI Generated

DOI: 10.1371/journal.ppat.1014727

Keywords: Plasmodium knowlesi, Plasmodium vivax, malaria, transcriptome, RNA-sequencing, parasitology, erythrocytes, gene expression, Plasmodium, knowlesi, A1-H, time