Project description:Profiling of gut gene expression in Cry1Ab-resistant and susceptible strains of Ostrinia nubilalis reveals possible adaptations of resistant larvae to transgenic Cry1Ab corn
Project description:Contiguous 14,535 and 14,536 nt near complete mitochondrial genome sequences respectively were obtained for Ostrinia nubilalis and Ostrinia furnicalis. Mitochondrial gene order was identical to that observed from Bombyx. Sequences comparatively showed 186 substitutions (1.3% sequence divergence), 170 CDS substitutions (131 at 3(rd) codon positions), and an excess of transition mutation likely resulting by purifying selection (d(N)/d(S) = omega congruent with 0.15). Overall substitution rates were significantly higher at 4-fold (5.2%) compared to 2-fold degenerate codons (2.6%). These are the 3(rd) and 4(th) lepidopteran mitochondrial genome reference sequences in GenBank and useful for comparative mitochondrial studies.
Project description:Stalk borers are major pests for some of the most important crops in the world, such as maize or rice. Plant defense mechanisms against these herbivores have been poorly investigated. The maize´s stalk responds to insect feeding activating defense genes including hormone biosynthetic-related or proteinase inhibitor transcripts. The most outstanding conclusion is that cells in the maize´s stalk undergo cell wall fortification after corn borer tunneling. We performed a gene expression profiling to identify those genes differentially expressed in maize after infestation with the corn borer S. nonagrioides.
Project description:We revealed a total of 398 gut genes differentially expressed (i.e., either up- or down-regulated genes with expression ratio ≥2.0) in S-strain larvae, while only 264 gut genes differentially expressed in R-strain larvae after fed transgenic corn leaves. Although the percentages of down-regulated genes among the total number of differentially expressed genes (199 genes or 50% in S-strain; 119 genes or 45% in R-strain) were similar between the R and S-strains, the expression ratios of down-regulated genes were much higher in S-strain than in R-strain. These results imply that R-strain larvae had an increased ability to deal with transgenic corn as compared with S-strain larvae. We also revealed that 17 and 9 significantly up- or down-regulated gut genes from S- and R-strain larvae, respectively, including serine proteases (trypsins and chymotrypsins) and aminopeptidases.
