ABSTRACT
In the search for new methods of pest control, the potential of RNA interference (RNAi) is being explored. Because the gut is the first barrier for the uptake of double-stranded (ds)RNA, pyrosequencing of the gut transcriptome is a powerful tool for obtaining the necessary sequences for specific dsRNA-mediated pest control. In the present study, a dataset representing the gut transcriptome of the Colorado potato beetle (CPB; Leptinotarsa decemlineata) was generated and analysed for the presence of RNAi-related genes. Almost all selected genes that were implicated in silencing efficiency at different levels in the RNAi pathway (core machinery, associated intracellular factors, dsRNA uptake, antiviral RNAi, nucleases), which uses different types of small RNA (small interfering RNA, microRNA and piwi-RNA), were expressed in the CPB gut. Although the database is of lower quality, the majority of the RNAi genes are also found to be present in the gut transcriptome of the tobacco hornworm [TH; Manduca sexta (19 out of 35 genes analysed)]. The high quality of the CPB transcriptome database will lay the foundation for future gene expression and functional studies regarding the gut and RNAi.
Subject(s)
Coleoptera/genetics , RNA Interference , Transcriptome , Animals , Gastrointestinal Tract , Gene Expression , Manduca/genetics , Phylogeny , RNA, Double-Stranded , RNA, Small InterferingABSTRACT
A full-length Hsp83, named SnoHsp83, cDNA from the corn stalk borer, Sesamia nonagrioides, was cloned and sequenced. Genomic analysis showed that the SnoHsp83 gene is unique. The size of the SnoHsp83 cDNA was found to be approximately 2.6 kb. The deduced polypeptide comprised 717 amino acid residues, with a molecular mass of 82.6 kDa. It contained all the highly conserved amino acid motifs that characterize the cytosolic members of the hsp90 family. We investigated the expression of SnoHsp83 gene in response to diapause and heat/cold stress. SnoHsp83 is constitutively expressed in non-diapausing larvae and is induced 15-fold by heat. SnoHsp83 displays a similar pattern to SnoHsc70 under diapause conditions, when extra larval moults occur. Our results indicate that the SnoHsp83 gene could be involved in the developmental process that occurs between two moults.
Subject(s)
Adaptation, Physiological/physiology , Gene Expression Regulation/physiology , Heat-Shock Proteins/metabolism , Hot Temperature , Moths/genetics , Moths/metabolism , Stress, Physiological/physiology , Amino Acid Sequence , Animals , Base Sequence , Computational Biology , DNA Primers/genetics , DNA, Complementary/genetics , Genomics , Molecular Sequence Data , Reverse Transcriptase Polymerase Chain Reaction , Sequence Alignment , Sequence Analysis, DNAABSTRACT
The complete cDNA sequences of Heat shock cognate protein 70 (SnoHsc70) and Heat shock protein 70 (SnoHsp70) were determined from the corn stalk borer Sesamia nonagrioides (Lef.). They encode 653 amino acids (Hsc70) and 633 amino acids (Hsp70), with calculated molecular masses of 71.5 kDa and 70.2 kDa respectively. SnoHsc70 is constitutively expressed, and SnoHsp70 is heat-inducible in non-diapausing insects. SnoHsp70 is down regulated during diapause, while SnoHsc70 is induced as the larvae enter deep diapause. High temperature stress during diapause has no further effect on transcript levels of SnoHsc70. Our results show that SnoHsc70 may play important roles in assisting protein conformation during specific stages of diapause.
