title: Transcriptional profiling analysis of Spodoptera litura larvae challenged with Vip3Aa toxin and possible involvement of trypsin in the toxin activation.
abstract: Vip proteins, a new group of insecticidal toxins produced by Bacillus thuringiensis, are effective against specific pests including Spodoptera litura. Here, we report construction of a transcriptome database of S. litura by de novo assembly along with detection of the transcriptional response of S. litura larvae to Vip3Aa toxin. In total, 56,498 unigenes with an N50 value of 1,853 bp were obtained. Results of transcriptome abundance showed that Vip3Aa toxin provoked a wide transcriptional response of the S. litura midgut. The differentially expressed genes were enriched for immunity-related, metabolic-related and Bt-related genes. Twenty-nine immunity-related genes, 102 metabolic-related genes and 62 Bt-related genes with differential expression were found. On the basis of transcriptional profiling analysis, we focus on the functional validation of trypsin which potentially participated in the activation of Vip3Aa protoxin. Zymogram analysis indicated that the presence of many proteases, including trypsin, in S. litura larvae midgut. Results of enzymolysis in vitro of Vip3Aa by trypsin, and bioassay and histopathology of the trypsin-digested Vip3Aa toxin showed that trypsin was possibly involved in the Vip3Aa activation. This study provides a transcriptome foundation for the identification and functional validation of the differentially expressed genes in an agricultural important pest, S. litura.
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Song
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Songqing
authors.initials: S
authors.lastname: Wu
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Ensi
authors.initials: E
authors.lastname: Shao
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Mengnan
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Xiong
authors.initials: X
authors.lastname: Guan
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, People's Republic of China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000201:enzymology; D020869:Gene Expression Profiling; D063990:Gene Ontology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D058977:Molecular Sequence Annotation; D059748:Proteolysis; D057057:Serine Proteases / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D001426:Bacterial Proteins; D019476:Insect Proteins; D007306:Insecticides; C447139:Vip3A protein, Bacillus thuringiensis; D057057:Serine Proteases