Molecular Identification and Functional Characterization of Vitellogenin Receptor From Harmonia axyridis (Coleoptera: Coccinellidae)

Abstract

Vitellogenin receptors (VgRs) have vital roles in reproduction by mediating endocytosis of the vitellogenin (Vg) in oviparous insects. Same as most insect species that possess only one VgR, in this study, a single VgR mRNA (HmVgR) was identified in an important natural enemy ladybeetle, Harmonia axyridis (Pallas). The open reading frame of HmVgR was 5,340 bases encoding a protein of 1,779 amino acids. Bioinformatic analyses showed that HmVgR had conserved domain motifs of low-density lipoprotein receptor family. Based on phylogenetic analysis, HmVgR had highly homologous within the Coleoptera. The transcriptional level of HmVgR was initially detected in the newly emerged female adults, gradually increased from day 3 to day 9, peaked on day 13, and then sharply decreased on day 15. Similar to most insects, HmVgR was expressed specifically in ovarian tissue. Moreover, RNA interference (RNAi) clearly decreased the transcription levels of HmVgR, which blocked the deposition of yolk protein in the ovaries, shortened the ovarian length, and led to negative impacts on reproductive-related parameters (i.e., prolonged preoviposition periods, reduced spawning and depressed hatchability). In sum, these results indicated that HmVgR may be critical for yolk protein deposition of oocytes and can play a key role in reproduction of female adults of H. axyridis. Our results provide conclusive proof for the important roles of HmVgR in fecundity, and establish a basis for further research on its interaction with vitellogenin.

Pannier is a key regulator of embryogenesis, pupal development and female reproduction in the insect pest Bactrocera dorsalis

“…42 Similarly, the RNAi-mediated silencing of HmVgR blocked the deposition of yolk protein in the ovaries, 43 and the silencing of the VgR gene extended the pre-ovipositional period and reduced the egg number and fertility in H. axyridis and Cadra cautella. 43,44 In Sogatella furcifera, the knockdown of SfVg and SfVgR reduced vitellin levels in the basal oocyte and resulted in the production of few or no complete oocytes. 45 Finally, previous studies in B. dorsalis showed that the down-regulation of BdVg and BdVgR disrupts ovarian growth, reduces ovary size and limits egg production.…”

“…In Corcyra cephalonica , the ovaries of females injected with CceVg double‐stranded RNA (dsRNA) were severely deformed, with short ovarioles, unordered egg sizes and few fully developed eggs 42 . Similarly, the RNAi‐mediated silencing of HmVgR blocked the deposition of yolk protein in the ovaries, 43 and the silencing of the VgR gene extended the pre‐ovipositional period and reduced the egg number and fertility in H. axyridis and Cadra cautella 43,44 . In Sogatella furcifera , the knockdown of SfVg and SfVgR reduced vitellin levels in the basal oocyte and resulted in the production of few or no complete oocytes 45 .…”

Molecular Characterization of Vitellogenin and Its Receptor in Spodoptera frugiperda (J. E. Smith, 1797), and Their Function in Reproduction of Female

“…This result is similar to that of S. litura and Chilo suppressalis (Walker) (Lepidoptera: Crambidae); that is, the expression of Vg and VgR can be first detected at the end of the pupa stage and increases rapidly in the adult stage [ 11 , 35 , 43 ]. The expression of Vg and VgR usually has a similar trend, and this expression pattern is closely related to the process of vitellogenesis and the state of ovarian development [ 3 , 44 ]. Thus, the expression of Vg and VgR could become new targets for forecasting the occurrence of pests in the field.…”

Insights from different reproductive gene knockdowns via RNA interference in the lady beetle Eriopis connexa: Establishing a new model for molecular studies on natural enemies

“…In Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), silencing RfVg extended the preoviposition period, reduced egg quantity, significantly lowered egg viability, and induced alterations in egg and ovary phenotypes (Rasool et al, 2021). In the ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), ds HaVgR ‐induced silencing led to a reduction in ovary size, an increase in the preoviposition period, and a decrease in the number of eggs (Han, Han, et al, 2022).…”