Transcriptome profiles of <i>Plasmodium vivax</i> and <i>Anopheles dirus</i> (Diptera: Culicidae) genes in sporozoite stage

Malaria is caused by the Plasmodium parasites transmitted by Anopheles mosquitoes. After ingestion by a mosquito vector, malaria parasite gametocytes differentiate into gametes and undergo fertilization in the midgut to form zygotes. The zygotes develop into ookinetes that traverse the midgut wall and form oocysts, within which sporozoites are produced. Our previous study characterized the transcriptome profiles of Plasmodium vivax and Anopheles dirus at the ookinete and oocyst stages. This study focused on the transcriptome analysis of An. dirus and P. vivax at 14-day post-infection, corresponding to the sporozoite stage. Transcripts corresponding to 1706 P. vivax genes were identified. Comparative transcriptomic analysis between P. vivax-infected and uninfected An. dirus revealed 112 upregulated, 599 downregulated and 8420 stably expressed genes. PvETRAMP10.3 and PvSS10 were highly expressed during the P. vivax sporozoite stage, suggesting potential roles in parasite infection competency. Upregulated An. dirus genes were associated with transcription processes, including DNA-dependent RNA polymerase activity, cholesterol transport and host defence mechanisms via C-type lectin domain-containing protein. In contrast, several genes associated with the innate immunity, host development and cellular homeostasis in An. dirus were downregulated. Notably, vitellogenin and regucalcin were drastically downregulated, suggesting potential roles in parasite-mosquito interactions during sporozoite infection. The expression patterns of selected An. dirus and P. vivax genes from RNA-Seq analysis were consistent with those determined by RT-qPCR, confirming the reliability of the transcriptomic data.