Chemosensory protein 4 is required for Bradysia odoriphaga to be olfactory attracted to sulfur compounds released from Chinese chives

Abstract

Bradysia odoriphaga (Diptera: Sciaridae) is a serious pest of Chinese chives cultivated in China. Chemosensory proteins (CSPs) are important components of insect olfactory systems that capture and bind environmental semiochemicals which are then transported to olfactory receptors. Despite their importance, the mechanism of olfaction and related behavioral processes in B. odoriphaga have not been characterized. Here, we found that BodoCSP4 has an important olfactory function. RT-qPCR indicated that BodoCSP4 expression was highest in the heads (antennae removed) of adult males, followed by the antennae of adult males. Competitive binding assays with 33 ligands indicated that BodoCSP4 binds well with methyl allyl disulfide, diallyl disulfide, and n-heptadecane; the corresponding dissolution constants (Ki) were as high as 5.71, 5.71, and 6.85 μM, respectively. 3D-structural and molecular docking indicated that BodoCSP4 has five α-helices and surrounds the ligand with certain hydrophobic residues including Leu60, Leu63, Leu64, Ala67, Val28, Ile30, Ile33, Leu34, and Val86, suggesting these residues help BodoCSP4 bind to ligands. Silencing of BodoCSP4 significantly decreased the attraction of B. odoriphaga males to diallyl disulfide and n-heptadecane but not to methyl allyl disulfide in Y-tube olfaction assays. These results increase our understanding of how BodoCSP4 contributes to host and female localization by B. odoriphaga males.

Characterization of CrufCSP1 and Its Potential Involvement in Host Location by Cotesia ruficrus (Hymenoptera: Braconidae), an Indigenous Parasitoid of Spodoptera frugiperda (Lepidoptera: Noctuidae) in China

“…The 3D model of CrufCSP1 revealed that it consists of four α-helices and four conserved cysteine residues, forming a hydrophobic pocket. This is different from other insect CSPs, which typically have five [54,55] or six α-helices [56,57]. We speculate that the CrufCSP1 has fewer α-helices, as this might lead to the formation of a larger hydrophobic pocket in its spatial conformation, making it more conducive to the entry of odor molecules and the formation of stable complexes.…”

Antennal transcriptome analysis reveals sensory receptors potentially associated with host detection in the livestock pest Lucilia cuprina

“…One of the CSP transcripts was highly expressed in both sexes and female biased (Table S6: D). Interestingly, in Bradysia odoriphaga Winnertz, 1867 (Diptera: Sciaridae), a CSP was associated with detection of sulfur-rich compounds [ 87 ], which are common attractants for blowflies [ 16 ]. Two TRPs were male biased (Table S6: K); however, the expression of these receptors was very low.…”

Involvement of Chemosensory Protein CrufCSP3 in Perception of the Host Location in a Parasitic Wasp Cotesia ruficrus

“…For instance, Yang et al found that the knockdown of BodoCSP4 in B. odoriphaga altered the preference for diallyl disulfide and nheptadecane. 48 Similarly, Maleszka et al reported that silencing AmelCSP5 in A. mellifera resulted in changes in embryonic development. 21 In R. padi, Peng et al demonstrated that knockdown of RpCSP4 and RpCSP6 significantly increased aphid mortality under sublethal concentrations of imidacloprid.…”

“…For instance, Yang et al found that the knockdown of BodoCSP4 in B. odoriphaga altered the preference for diallyl disulfide and n-heptadecane . Similarly, Maleszka et al reported that silencing AmelCSP5 in A.…”