Transcriptome Analysis Of Symbiont Of Rabditid Entomopathogenic Nematodes,Heterorhabditidoide-Serratia

Heterorhabditidoides belongs to the family Rhabditidae,is a novel member of entomopathogenic nematodes(EPNs).Our preliminary studies found that it had strong pathogenicity to some pests in orders Lepidoptera,Diptera and Coleoptera pests,and shew some biological activities related to inflammation and immune response.However the information about the genome of species of the genus is quite scarce,and their interactions mechanism with symbiotic bacteria and related insecticidal mechanism are not clear.In order to further understand the symbiotic related mechanism of this symbiont,total RNAs of different development stages of two species of the genus Heterorhabditidoides associated respectively with their symbiotic bacterial strains were extracted and sequenced by high-throughput De novo sequencing.Gene expression and regulation in genome-wide range are able to be analyzed based on the transcriptome level.Information of gene annotation and function classification are obtained by comparing with basic local alignment search tool(BLAST).Main results are as followings:(1)A total of 34,187 unigenes(mean length =770 nt,N50 =1300 nt)were assembled from 54.3 million clean reads.(2)Using the public databases including NR,COG,Swiss-Prot,GO,KEGG and NT,we find that a total of 21,255 unigenes could be matched the above-mentioned database,accounting for 62.2%of the total unigenes.GO analysis shows that 12,416 unigenes could be matched to the biological process,cellular component,molecular function ontology,of which the gene involves Single organism process,Cell,Binding constitutes most of it.Compared with the COG database,we find that 8,332 unigenes could be matched to 25 functional categories.KEGG pathway analysis shows that 14,066 unigenes could be matched to 257 diverse biological pathways.Then we get 942 SSR markers by the SSR analysis.The distribution of typetri-nucleotide repeats SSR type is the most,followed by di-riucleotide repeats and mono-nucleotide repeats.The three SSR types accounted for 98%of the total SSR,the left SSR types only account for 2%.We have detected 153,084 SNP polymorphic sites in Heterorhabditidoides-serratia by using the SNP analysis.The result shows that the transition types and transversion types respectively accounted for 68.9%and 31.1%of the total variation.At last,we predicted some important biological pathways,such as the secretion of Fibrinolytic protein,growth and development,aging,immune of EPNs and the pathogenicity of symbiotic bacteria.