Pébrine disease is a fetal disease of silkworm caused by Nosema bombycis. Without effective measure to be controled, this disease leads to enormous economic losses every year. To find some tools or targets which are helpful for preventing this disease, we initiated the Nosema bombycis Genome Project (NBGP), by which we sequenced the genome of N. bombycis CQ1 isolate.

Nosema bombycis CQ1 (NbCQ1) was isolated from infected silkworms in Chongqing, China. The biological features of the NbCQ1 were then studied after the isolation in 1984.

Genomic DNA and mRNA of NbCQ1 were extracted, from which a plasmid library (with 1.5-2Kb inserts), a miniBAC library (with 30-50Kb inserts), a Solexa DNA library and cDNA libraries were constructed. By sequencing, we finally obtained about 6.7X Sanger reads of plasmid library, 0.4X miniBAC ends (~10X physical coverage), ~28X Solexa reads (Table 1).

Table 1. Summary of library construction and sequencing.

All sequenced reads were assembled and constructed 1,605 scaffolds, with total length 15.7Mb and N50 length 57Kb. From this assembly, the repetitive sequences, protein-coding genes, rRNA genes and tRNA genes were predicted. Finally, we got about 5,000 predicted protein-coding genes, 84 rRNA genes and 175 tRNA genes. Notably, the repetitive sequence occupies about 39% of the whole genome.