Insect Mouthpart Transcriptome Unveils Extension of Cuticular Protein Repertoire and Complex Organization

Abstract

First transcriptome of aphid retort glands and stylet cuticular protein compositionA pyrokinin transcript is mandibular gland specific at the onset of adult moult Stylet cuticle is of higher protein complexity than other insect cuticles A new class of lowcomplexity cuticular proteins is predicted

Cuticular Structure Proteomics in the Pea Aphid Acyrthosiphon pisum Reveals New Plant Virus Receptor Candidates at the Tip of Maxillary Stylets

“…It is notable that the cuticle of antennae, legs, and wings originates from epithelial cells, while that of the stylets is synthesized by the highly specialized retort glands entirely dedicated to cuticle production. ,, This sole ontology difference may lead to cuticles with different degrees of protein complexity. However, a recent characterization of transcripts in the retort glands revealed a more complex set of expressed CP genes than in other previously characterized cuticular transcriptomes . Our MS data show that over 50% of the stylet CPs were identified by a single peptide, sometimes covering less than 2% of the mature protein, suggesting that CPs are hardly extractable from this organ and perhaps explaining the low complexity of the corresponding proteome.…”

“…This striking observation suggests that proteins in this structure may be tightly cross-linked and no longer detectable with our antibodies or, as hypothesized above, that these stylets have surface properties that do not give access to the embedded cuticular proteins. Both hypotheses assume a comparable protein constitution for maxillary and mandibular stylets, consistent with their undistinguishable transcript profiles reported earlier …”

“…Stylet bundles, hereafter named stylets, are approximately 700 μm in length and 3 μm in diameter for A. pisum adults. They are anchored in aphid heads in the glands from which they are secreted, the retort organs (described by Ponsen and Guschinskaya and colleagues). , To extract exploitable information from MS analysis, hundreds of stylets had to be pooled for each trial as free as possible of other contaminating aphid tissues. In addition, we had to reduce electrostatic charges that too often induced stylets fly off and loss.…”

Three-dimensional reconstruction of a whole insect reveals its phloem sap-sucking mechanism at nano-resolution

“…For virus vectors from the order of Hemiptera, including small/tiny insects like planthoppers, leafhoppers, psyllids, aphids, and whiteflies, studying their phloem sap-sucking mechanism will enable us to understand the way they injure crops and inject their saliva with transmitted viruses into crop tissues. Knowledge about their internal structures such as the mouthparts and alimentary canal of the phloem sap-sucking Diaphorina citri (Hemiptera: Liviidae) ( Ammar et al, 2017 ), Psammotettix striatus (Hemiptera: Cicadellidae) ( Zhang et al, 2012 ), and the aphid Acyrthosiphon pisum (Hemiptera: Aphididae) ( Guschinskaya et al, 2020 ) is restricted to studies that relied on some discrete images by either light, confocal, or electron microscopy. Study of phloem–sucking insect/pathogen interactions represents an exciting frontier of plant science ( Jiang et al, 2019 ).…”

A salivary factor binds a cuticular protein and modulates biting by inducing morphological changes in the mosquito labrum

“…Interestingly, cuticular proteins are also key constituents of the tip of the mouth apparatus of other piercing-sucking insects, the aphids, which feed on plants and can transmit plant viruses. [50][51][52][53][54][55] In these insects, the tip of the maxillary stylet hosts a structure known as acrostyle with high concentration of cuticular proteins. Some viruses can interact with these proteins to ensure ll OPEN ACCESS plant-to-plant mechanical transmission.…”