Proteomic Analysis of Apis cerana and Apis mellifera Larvae Fed with Heterospecific Royal Jelly and by CSBV Challenge

Abstract

Chinese honeybee Apis cerana (Ac) is one of the major Asian honeybee species for local apiculture. However, Ac is frequently damaged by Chinese sacbrood virus (CSBV), whereas Apis mellifera (Am) is usually resistant to it. Heterospecific royal jelly (RJ) breeding in two honeybee species may result in morphological and genetic modification. Nevertheless, knowledge on the resistant mechanism of Am to this deadly disease is still unknown. In the present study, heterospecific RJ breeding was conducted to determine the effects of food change on the larval mortality after CSBV infection at early larval stage. 2-DE and MALDI-TOF/TOF MS proteomic technology was employed to unravel the molecular event of the bees under heterospecific RJ breeding and CSBV challenge. The change of Ac larval food from RJC to RJM could enhance the bee resistance to CSBV. The mortality rate of Ac larvae after CSBV infection was much higher when the larvae were fed with RJC compared with the larvae fed with RJM. There were 101 proteins with altered expressions after heterospecific RJ breeding and viral infection. In Ac larvae, 6 differential expression proteins were identified from heterospecific RJ breeding only, 21 differential expression proteins from CSBV challenge only and 7 differential expression proteins from heterospecific RJ breeding plus CSBV challenge. In Am larvae, 17 differential expression proteins were identified from heterospecific RJ breeding only, 26 differential expression proteins from CSBV challenge only and 24 differential expression proteins from heterospecific RJ breeding plus CSBV challenge. The RJM may protect Ac larvae from CSBV infection, probably by activating the genes in energy metabolism pathways, antioxidation and ubiquitin-proteasome system. The present results, for the first time, comprehensively descript the molecular events of the viral infection of Ac and Am after heterospecific RJ breeding and are potentially useful for establishing CSBV resistant populations of Ac for apiculture.

Evidence of Apis cerana Sacbrood virus Infection in Apis mellifera

“…Although the A. mellifera larvae infected with AcSBV under either laboratory or field conditions had no obvious signs of the disease, as demonstrated in previously reported experiments (31)(32)(33), AcSBV negative-strand RNA could be detected in A. mellifera larvae (Fig. 4B and D), which suggests that the genome of AcSBV is able to replicate in A. mellifera larvae.…”

“…Most previous studies (31)(32)(33) concluded that there was no crossspecies infection between AcSBV and AmSBV, based on the pathogenicity in larvae during the course of the experiments. However, an A. mellifera isolate, AmSBV-Kor19 (GenBank accession number JQ390592), was found to be distinct from other A. mellifera isolates in the genome (26) and clustered together with A. cerana isolates in the phylogenetic tree (29).…”

“…To determine the effects of AcSBV on the mortality and infection rates of third-instar larvae, which represent the most sensitive stage for SBV infection (39), second-instar larvae of A. cerana and A. mellifera were carefully transferred to 48-well culture plates containing 150 l artificial diet (40) and then were placed in an incubator set at 34 Ϯ 0.5°C, with 70% Ϯ 5% relative humidity (Stik, Shanghai, China). The second-instar larvae were obtained as described previously (33). After 24 h, the third-instar larvae of A. cerana and A. mellifera were transferred individually to other 48-well culture plates containing 130 l artificial diet, as described above.…”

“…To understand the susceptibilities of A. cerana and A. mellifera bees to SBV isolated from different honeybee species, studies of cross-species infections with AcSBV and AmSBV were performed. In previous cross-infection studies conducted using AcSBV and AmSBV to challenge A. mellifera larvae and A. cerana larvae, AmSBV and AcSBV were pathogenic only in A. mellifera larvae and A. cerana larvae, respectively (31)(32)(33).…”

Prevalence of bee viruses in Apis cerana cerana populations from different locations in the Fujian Province of China

“…A . c. cerana is more susceptible to CSBV, whereas A. mellifera is less susceptible (Shan et al., ; Zhang, Zhang, Huang, & Han, ). CSBV has created a severe outbreak in A .…”