| Microsporidia is an obligate intracellular eukaryotic parasite that can infect almost all the animals including human and economical insects ( such as silkworm and honeybees etc ) . Antheraea pernyi is an important economical insect and its faeces contain lots of nutrient and proteins which is also widely used as eatable materials . Nosema antheraeae is the parasite of Antheraea pernyi and can result in the damage of A.pernyi cultivation .In this study , Illumina sequence technology was used to survey the genome of Nosema antheraeae , longer than 500 bp shotgun fragments were sequenced by pair-end sequence method . 657 Mbp clean data was obtained , after SOAPdenovo assembly , 3536 scaffolds and 5266 contigs was obtained , the total length of scaffolds was 5797972 bp , covered about 67% of whole genomic sequences , N50 of all scaffolds was 2417 bp , the content of GC was 27.96% , ORFs were predicted by Glimmer , blast was used to search the nr database , swissprot database , trembl database and KEGG database to annotate the ORFs , the result were :In total , 3413 genes were predicted , after blast of COG , KOG databases and statistic analysis , all genes were classified into 25 kinds . They were DNA replication related genes , general function prediction only related genes , translation related genes , transcription related genes , intracellular trafficking related genes , carbohydrate transport related genes , cell cycle related genes , function unknown genes , signal transduction related genes , cytoskeleton related genes , lipid transport related genes , inorganic ion transport related genes , RNA processing related genes , chromatin structure and dynamics related genes , energy production related genes , nucleotide and amino acid transport related genes , cell wall related genes , coenzyme transport related genes , defense related genes , secondary metabolites biosynthesis related genes , nuclear structure related genes , cell motility related genes and extracellular structures related genes etc . Among these genes , replication , recombination related genes , general function prediction only related genes and translation related genes were in a higher proportion of the total genes , the percent of these genes was more than 10% .Comparison analysis of GO classification of N.antheraeae , N.bombycis and N.ceranae indicated that , there was no significant gene distribution difference between the three microsporidian species .Comparison analysis of orthologs suggested that , N.antheraeae had 81% orthologs to N.bombycis, N.antheraeae had 62% orthologs to N.ceranae , N.antheraeae had 51% orthologs to all three microsporidian species’genes .According to the previous studies it was supposed that spore wall proteins of E.cuniculi made a role in the process of E.cuniculi’s infection in the host . So , research of spore wall proteins could help to elucidate the mechanisms of parasite-host interactions .SDS-PAGE and LC-MS method were used to identify the vacant spore proteins of Nosema antheraeae . 6 proteins were identified by Mascot software , three spore wall proteins were selected to be multi-aligned , suggesting that relationship between Nosema bombycis and Nosema antheraeae was more near than between Nosema antheraeae and other microsporidia . The ratio of nonsynonymous substitution rate ( dN ) and synonymous substitution rate ( dS ) between spore wall proteins of microsporidia was less than 1 , suggesting that spore wall proteins were subjected to purified selection between microsporidia , and were considerably conserved among microsporidia . Out results made a good foundation for studying the spore wall protein and their functions in Nosema antheraeae . |
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