Characterization of microsporidian genome fragments found in the genome of Asian swallowtail

抄録

 The larvae of the Asian swallowtail, Papilio xuthus, are important herbivorous pests of citrus fruits. Our post-genome studies on Nosema bombycis, a silkworm pathogen that causes serious economic losses to the sericultural industry, showed that some genes of N. bombycis were highly similar to those of P. xuthus. Most microsporidia-specific genes encoding 3 polar tube proteins and 12 spore wall proteins in N. bombycis were found in the genome of P. xuthus with high homology. A comparison of the genome revealed that 92.4% of scaffolds of the genome of N. bombycis were found in P. xuthus. The 185 scaffolds of P. xuthus consisted of 19.6 Mb of DNA, covering the genome size of all species of genome-determined microsporidia. In contrast, 113 scaffolds of the genome of N. bombycis were assigned to the chromosomal DNA of bacteria (Klebsiella, Pseudomonas, Luteibacter, Enterobacter, Paraburkholderia, and Raoultella) and five scaffolds were assigned to the genome of B. mori with high identity. Our findings suggest that when conducting post-genome research, we should take into account that the genome assembly data registered in National Center of Biotechnology Information could be sometimes contaminated with the genome of other organisms.