Preliminary expression profile of western corn rootworm, Diabrotica virgifera virgifera, neonates challenged with Cry34Ab1 and Cry35Ab1 by next-generation sequencing

Wednesday, November 13, 2013
Exhibit Hall 4 (Austin Convention Center)
Haichuan Wang , Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE
Seong-il Eyun , School of Biological Sciences-Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE
Kanika Arora , Dow AgroSciences LLC, Indianapolis, IN
Sek Yee Tan , Dow AgroSciences LLC, Indianapolis, IN
Premchand Gandra , Dow AgroSciences LLC, Indianapolis, IN
Etsuko Moriyama , Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE
Chitvan Khajuria , Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE
Jessica D. Jurzenski , Department of Entomology, University of Nebraska, Lincoln, NE
Huarong Li , Dow AgroSciences LLC, Indianapolis, IN
Maia Donahue , Dow AgroSciences LLC, Indianapolis, IN
Kenneth Narva , Dow AgroSciences LLC, Indianapolis, IN
Blair Siegfried , Department of Entomology, University of Nebraska, Lincoln, NE
Next Generation Sequencing technologies are routinely used to investigate gene expression and regulation as they relate to various environmental challenges. In this study, total RNA was extracted from whole bodies of Diabrotica virgifera virgifera (LeConte) (Western Corn Rootworm, WCR) neonates challenged with Cry34Ab1, Cry35Ab1, and the combination of Cry34Ab1/Cry35Ab1 Bt toxin for 24 hrs, plus a buffer control.  Each sample was sequenced separately on an Illumina Genome Analyzer followed by transcriptome assembly for all 4 treatments. With filtered reads (Q>30), the Trinity assembler generated four transcriptome data sets for Cry34Ab1, Cry35Ab1, Cry34/35Ab1 and buffer control, respectively, plus a reference transcriptome assembled from combining all reads with average contig length of  ~950 (201-31457) bp. The number of transcripts created using Trinity varied from 58,256 to 60,202 among the four treatments. In total, 44,542 transcripts were shared among all four treatments as compared to the reference. DESeq and NOISeq were used to compare gene expression among treatments.  The number of genes up- or down-regulated varied among the treatments. The Cry34/35Ab1 treatment exhibited the greatest number of differentially regulated genes and the total number of transcripts that were up- and down-regulated was up to 5-fold greater than either toxin alone. This information is consistent with Cry34Ab1 and Cry35Ab1 proteins acting as a binary toxin in WCR larvae. 

Key words: Cry34Ab1, Cry35Ab1, bioassay, RNAseq

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