Differential expression profiles and potential function of piRNAs in Apis mellifera ligustica workers under Nosema ceranae stress

Abstract:

To explore the differential expression profile and potential function of piRNAs in Apis mellifera ligustica workers under Nosema ceranae stress, the differentially expressed piRNA (DEpiRNAs) in the host response to stress were screened out by using previously abtained transcriptome data from A. m. ligustica workers’ midguts at 7 days post inoculation (dpi) and 10 dpi (AmT1 and AmT2 groups) as well as corresponding un-inoculated workers’ midguts (AmCK1 and AmCK2 groups), followed by prediction and investigation of target mRNAs of DEpiRNAs with relevant software, and randomly selected DEpiRNAs were further validated by Stem-loop RT-PCR and qPCR. The results showed that 50 and 207 DEpiRNAs were screened out from AmCK1 vs AmT1 and AmCK2 vs AmT2 comparison groups, respectively; there are 10 common DEpiRNAs shared by the aforementioned two comparison groups, and the numbers of unique DEpiRNAs were 40 and 197, respectively; the consensus DEpiRNA piR-ame-1128833 can target 3021 mRNAs; Stem-loop RT-PCR result confirmed the true expression of four DEpiRNAs; RT-qPCR result verified that the expression trend of four DEpiRNAs was in accordance with that in the sequencing data. These results reveal that the expression pattern of piRNAs in the midguts of A. m. ligustica workers was altered due to N. ceranae stress. DEpiRNA potentially regulated host response to N. ceranae stress through targeting associated mRNAs.