Anopheline mosquitoes are the sole vectors of malaria and rely on olfactory cues for host seeking in which ammonia derived from human sweat plays an essential role. To investigate the function of the Anopheles coluzzii ammonium transporter (AcAmt) in the mosquito olfactory system, we generated an AcAmt null mutant line using CRISPR/Cas9. AcAmt^−/− mutants displayed a series of novel phenotypes compared with wild-type mosquitoes including significantly lower insemination rates during mating and increased mortality during eclosion. Furthermore, AcAmt^−/− males showed significantly lower sugar consumption while AcAmt^−/− females and pupae displayed significantly higher ammonia levels than their wild-type counterparts. Surprisingly, in contrast to previous studies in Drosophila that revealed that the mutation of the ammonium transporter (DmAmt) induces a dramatic reduction of ammonia responses in antennal coeloconic sensilla, no significant differences were observed across a range of peripheral sensory neuron responses to ammonia and other odorants between wild-type and AcAmt^−/− females. These data support the existence in mosquitoes of novel compensatory ammonia-sensing mechanisms that are likely to have evolved as a result of the importance of ammonia in host-seeking and other behaviors.

按蚊是疟疾的唯一媒介，依靠嗅觉线索寻找宿主，其中来自人类汗液的氨起着重要作用。为了研究按蚊氨转运蛋白 ( AcAmt ) 在蚊子嗅觉系统中的功能，我们使用 CRISPR/Cas9 生成了一个AcAmt无效突变系。与野生型蚊子相比， AcAmt ^-/-突变体显示出一系列新的表型，包括在交配期间显着降低的授精率和在羽化期间增加的死亡率。此外，AcAmt ^-/-男性的糖消耗量显着降低，而AcAmt ^-/-雌性和蛹的氨水平明显高于野生型。令人惊讶的是，与之前对果蝇的研究表明，铵转运蛋白 ( DmAmt ) 的突变导致触角体腔感受器中的氨反应显着降低，但在一系列外周感觉神经元对氨和其他反应的反应中没有观察到显着差异。野生型和AcAmt ^-/-雌性之间的气味。这些数据支持蚊子中存在新的补偿性氨传感机制，这些机制可能是由于氨在寻找宿主和其他行为中的重要性而进化的。