Despite the critical role of Plasmodium sporozoites in malaria transmission, we still know little about the mechanisms underlying their development in mosquitoes. Here, we use single-cell RNA sequencing to characterize the gene expression profiles of 16,038 Plasmodium berghei sporozoites isolated throughout their development from midgut oocysts to salivary glands, and from forced salivation experiments. Our results reveal a succession of tightly regulated changes in gene expression occurring during the maturation of sporozoites and highlight candidate genes that could play important roles in oocyst egress, sporozoite motility, and the mechanisms underlying the invasion of mosquito salivary glands and mammalian hepatocytes. In addition, the single-cell data reveal extensive transcriptional heterogeneity among parasites isolated from the same anatomical site, suggesting that Plasmodium development in mosquitoes is asynchronous and regulated by intrinsic as well as environmental factors. Finally, our analyses show a decrease in transcriptional activity preceding the translational repression observed in mature sporozoites and associated with their quiescent state in salivary glands, followed by a rapid reactivation of the transcriptional machinery immediately upon salivation.

尽管疟原虫子孢子在疟疾传播中起着关键作用，但我们对其在蚊子中发育的潜在机制仍知之甚少。在这里，我们使用单细胞 RNA 测序来表征 16,038伯氏疟原虫的基因表达谱子孢子在从中肠卵囊到唾液腺的整个发育过程中以及从强迫流涎实验中分离出来。我们的研究结果揭示了在子孢子成熟过程中发生的一系列严格调控的基因表达变化，并突出了可能在卵囊排出、子孢子运动以及蚊子唾液腺和哺乳动物肝细胞入侵的潜在机制中发挥重要作用的候选基因。此外，单细胞数据揭示了从同一解剖部位分离的寄生虫之间广泛的转录异质性，表明疟原虫蚊子的发育是异步的，受内在和环境因素的调节。最后，我们的分析表明，在成熟子孢子中观察到的翻译抑制之前转录活性下降，这与它们在唾液腺中的静止状态有关，随后在唾液分泌后立即快速重新激活转录机制。