Transcritpome sequencing analysis of an infected bursa of fabricius

Abstract

The virus infects young chickens and brings immunosuppression and mortality at three to six weeks of age. Previously, with the use of cDNA microarray,we demonstrated that a number of transcripts expressed differentially in IBDV-infected chicken embryonic fibroblasts. In general, cell surface receptors involved in B cell and T cell activation and differentiation were suppressed, while the target genes and inducers of NFkB and the genes involved in toll-like receptor- and interferon-mediated responses were up-regulated. Though cDNA microassay assay provides a general picture on in vitro host cell responses in IBDV infection, there are still many information gaps in the pathogenesis pathway to be completed. We conducted deep transcriptome sequencing on the IBDV infected bursa of Fabricius. Entire bursas were collected from both healthy and infected chickens that showed typical Gumboro symptoms at 20 d of age. Total RNA and poly-A+ RNA were isolated from the organ followed by double-stranded cDNA synthesis. Complementary DNA libraries were then constructed followed by emulsion PCR amplification. Sequences of these transcriptomes were then analyzed by 454 GS Junior System. After sequence assembly, more than 3000 contigs were obtained in each transciptome and the sequences of contigs were blasted against public databases. Apart from the identification of transcript species, expression level of each transcript was also reflected by the magnitude of coverage in each sequence contig. To conclude, we made use of deep transcritpome sequencing method to identify the difference between the entire transcritpome of control and infected chicken bursa, and hence provide detail information on the host cell defense and viral pathogenic mechanisms upon IBDV infection.