Nosema bombycis CQ1

Category
Microsporidia
Phylum
Microsporidia
Class
-
Order
Apansporoblastina
Family
Nosematidae
Genus
Nosema
Species
bombycis
Strain
CQ1
Host
Silkworm
Status
Draft
Source
SKLSGB, SWU

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.

Silkworm pebrine disease and Nosema bombycisSilkworm pebrine disease and Nosema bombycis

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.

 Insert sizeTotal length (Mb)Sequence depth (X)Ave. read length (bp)Total reads
Mini-BAC ends10-30 Kb6.560.4248013,673
Plasmid ends2 Kb104.246.62451231,293
8 Kb2.130.144554,694
Solexa500 bp443.3628.2752,955,733
All556.2935.38

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.

Data summary of N. bombycis CQ1 genome

Data TypeRecordsLength (bp or aa)
Assembly160515680459
Gene44583341231
mRNA44583341231
Protein44581109599
rRNA8451872
tRNA17512999
Exon44723407190
DAN Transposon14052879188
LINE Element105222325
SINE Element4028669
LTR Retrotransposon253611288
Repeat Region39912342831

References:

  • Pan G, Xu J, Li T, Zhou Z, et al. Comparative genomics of parasitic silkworm microsporidia reveal an association between genome expansion and host adaptation. BMC Genomics, 2013, 14: 186. [PubMed]