Résumé
Aphids are serious agricultural pests capable of making direct damages to crops and, more importantly, of transmitting hundreds of species of pathogens that cause considerable losses worldwide. Their piercing-sucking mouthparts are well-adapted structures to pierce plant tissues and uptake sap and nutrients from their host plants. They consist of four long needle-like cuticular stylets, two outer mandibles and two inner maxillae synthesized at each molt by specialized cuticular glands known as the Retort Organs (ROs). Our work has shown that proteins are not uniformly distributed in the stylets conferring local functionalization of cuticular micro-territories such as the acrostyle at the tip of maxillary stylets with stylin proteins emerging on its surface involved in virus binding. To better understand when and how the acrostyle is synthesized, we decided to explore the biogenesis of the stylets throughout the preimaginal stage of the aphid species Acyrthosiphon pisum. In this study, we used X-ray synchrotron-based micro-tomography, a non-destructive approach allowing the reconstruction of highly-resolved 3D images of internal organs. Datasets were collected at the synchrotron facility of the Paul Scherrer Institute (Villigen, CH) on synchronized aphids sampled at key time points of the 4th instar nymph and adult stages. This comparative analysis highlighted morphological and volumetric changes of the ROs during aphid development and cuticle secretion and provide an unprecedented level of detail on the complex biological process of de novo stylet synthesis.