Molecular and Functional Characterization of Trehalase in the Mosquito Anopheles stephensi

Abstract

Like other insects, in blood-feeding mosquitoes, trehalase (TRE; EC 3.2.1.28), an enzyme that metabolizes trehalose, may influence a wide array of functions including flight, survival, reproduction, and vectorial capacity, but its role has not been investigated in detail. Here, we characterized a 1,839-bp-long transcript, encoding a 555-aa-long trehalase-2 homolog protein from the mosquito <i>Anopheles stephensi</i>. With a conserved insect homology, and in <i>silico</i> predicted membrane-bound protein, we tested whether trehalase (<i>As-TreH</i>) also plays a role in mosquito physiologies. Constitutive expression during aquatic development or adult mosquito tissues, and a consistent upregulation until 42 h of starvation, which was restored to basal levels after sugar supply, together indicated that <i>As-TreH</i> may have a key role in stress tolerance. A multifold enrichment in the midgut (<i>p</i> < 0.001819) and salivary glands (<i>p</i> < 4.37E-05) of the <i>Plasmodium vivax-</i>infected mosquitoes indicated that <i>As-TreH</i> may favor parasite development and survival in the mosquito host. However, surprisingly, after the blood meal, a consistent upregulation until 24 h in the fat body, and 48 h in the ovary, prompted to test its possible functional correlation in the reproductive physiology of the adult female mosquitoes. A functional knockdown by dsRNA-mediated silencing confers <i>As-TreH</i> ability to alter reproductive potential, causing a significant loss in the egg numbers (<i>p</i> < <i>0.001</i>), possibly by impairing energy metabolism in the developing oocytes. Conclusively, our data provide initial evidence that <i>As-TreH</i> regulates multiple physiologies and may serve as a suitable target for designing novel strategies for vector control.