Identification of Immune Response to Sacbrood Virus Infection in Apis cerana Under Natural Condition

Abstract

Chinese sacbrood virus (CSBV) is a serious threat to eastern honeybees (Apis cerana), especially larvae. However, the pathological mechanism of this deadly disease remains unclear. Here, we employed mRNA and small RNA (sRNA) transcriptome approach to investigate the microRNAs (miRNAs) and small interfering RNAs (siRNAs) expression changes of A. cerana larvae infected with CSBV under natural condition. We found that serine proteases involved in immune response were down-regulated, while the expression of siRNAs targeted to serine proteases were up-regulated. In addition, CSBV infection also affected the expression of larvae cuticle proteins such as larval cuticle proteins A1A and A3A, resulting in increased susceptibility to CSBV infection. Together, our results provide insights into sRNAs that they are likely to be involved in regulating honeybee immune response.

Structure of the Midgut of the Queen Bee <i>Apis mellifera</i> <I>L.</I> Naturally Infected with <i>Sacbrood virus</i> (SBV)

“…Bees belonging to Apis mellifera are more resistant to SBV infection compared to Apis cerana bees [13,38].…”

“…At a time when the honey bee's body is developing new defenses against the pathogen, the latter is forced to adapt its own strategy of invasion and infection to counteract the host's immune defenses. Therefore, it has been suggested that the more stable the immunity of bees, the more often more pathogenic strains will be detected, and this in turn will accelerate the evolution of pathogens [27,[37][38][39][40][41].…”

Expression Profile, Regulatory Network, and Putative Role of microRNAs in the Developmental Process of Asian Honey Bee Larval Guts

“…Previously, by performing small RNA-seq (sRNA-seq) and bioinformatics, we discovered 560 miRNAs in the Apis mellifera ligustica larval guts [ 23 ] and deciphered the expression profile as well as regulatory network of miRNAs across the developmental process of larval guts [ 24 ]. Currently, limited studies have shown that A. cerana miRNAs are potentially involved in response to fungi or viruses [ 25 , 26 ]. For example, Deng et al [ 26 ] identified a total of 23 differently expressed miRNAs (DEmiRNAs) in A. cerana larvae upon CSBV infection and inferred that ame-miR-3759 may play a key part in melanin synthesis during larval response.…”

“…Currently, limited studies have shown that A. cerana miRNAs are potentially involved in response to fungi or viruses [ 25 , 26 ]. For example, Deng et al [ 26 ] identified a total of 23 differently expressed miRNAs (DEmiRNAs) in A. cerana larvae upon CSBV infection and inferred that ame-miR-3759 may play a key part in melanin synthesis during larval response. Recently, we identified 435 miRNAs in the larval guts of A. c. cerana , the nominate subspecies of A. cerana , based on sRNA-seq and bioinformatics and further confirmed the sequences of six miRNAs and the expression of five miRNAs using molecular approaches [ 27 ].…”

Age and Behavior-Dependent Differential miRNAs Expression in the Hypopharyngeal Glands of Honeybees (Apis mellifera L.)

“…MicroRNA (miRNA) is a class of small (18–24 nt), single-strand, and endogenous ncRNA that plays important roles in the post-transcriptional regulation of target gene expression [ 16 , 17 ] related to various biological processes, such as tissue development [ 18 ]. Previous studies on honeybee miRNAs revealed their key roles in mediating diverse physiological processes, such as caste differentiation [ 19 , 20 ], division of labor [ 21 , 22 ], memory formation [ 23 , 24 ], queen reproductive performance [ 25 , 26 ], immune defense [ 27 , 28 ], and embryonic and midgut development [ 29 , 30 ]. However, little is known about whether/how miRNAs regulate the HPGs development in worker bees.…”