Screening of Differentially Expressed Microsporidia Genes from Infected Honey Bees by Suppression Subtractive Hybridization.

The microsporidium is a high prevalent parasite of the European honey bee (). This parasite is spreading across the world into its novel host. The developmental process, and some mechanisms of -infected honey bees, has been studied thoroughly; however, few studies have been carried out in the mechanism of gene expression in during the infection process. We therefore performed the suppressive subtractive hybridization (SSH) approach to investigate the candidate genes of during its infection process. All 96 clones of infected (forward) and non-infected (reverse) library were dipped onto the membrane for hybridization. A total of 112 differentially expressed sequence tags (ESTs) had been sequenced. For the host responses, 20% of ESTs (13 ESTs, 10 genes, and 1 non-coding RNA) from the forward library and 93.6% of ESTs (44 ESTs, 28 genes) from the reverse library were identified as differentially expressed genes (DEGs) of the hosts. A high percentage of DEGs involved in catalytic activity and metabolic processes revealed that the host gene expression change after infection might lead to an unbalance of physiological mechanism. Among the ESTs from the forward library, 75.4% ESTs (49 ESTs belonged to 24 genes) were identified as genes. Out of 24 genes, nine DEGs were subject to real-time quantitative reverse transcription PCR (real-time qRT-PCR) for validation. The results indicated that these genes were highly expressed during infection. Among nine genes, one gene (AAJ76_1600052943) showed the highest expression level after infection. These identified differentially expressed genes from this SSH could provide information about the pathological effects of . Validation of nine up-regulated genes reveal high potential for the detection of early nosemosis in the field and provide insight for further applications.