Insights into the transcriptomics of polyphagy: Bemisia tabaci adaptability to phenylpropanoids involves coordinated expression of defense and metabolic genes

ABSTRACT: Background: The whitefly Bemisia tabaci is a major generalist agricultural pest of field and horticultural crops world-wide. Despite its importance, the molecular bases of defense mechanisms in B. tabaci against major plant secondary defense compounds, such as the phenylpropanoids, remain unknown. Results: Our experimental system utilized transgenic Nicotiana tabacum plants constitutively expressing the PAP1 M-bM-^AM-^D AtMYB75 transcription factor which activates specifically the phenylpropanoid / flavonoids biosynthetic pathway. Our study used suppression subtractive hybridization (SSH) and cDNA microarray approaches to compare gene expression between B. tabaci adults subjected to wild-type or transgenic plants for six hours. A total of 2880 clones from the SSH libraries were sequenced. Both the SSH and cDNA microarray analyses indicated a complex interaction between B. tabaci and secondary defense metabolites produced by the phenylproapnoids / flavonoids pathway, involving enhanced expression of detoxification, immunity, oxidative stress and general stress related genes as well as general metabolism and ribosomal genes. Quantitative PCR revealed significant changes in the expression of several of these genes in response to feeding on artificial diet containing the flavonol quercetin. The elevated transcriptional activity was not accompanied by reduced reproductive performance, indicating high adaptability of B. tabaci to this large group of plant secondary defense metabolites. Conclusion: Results of this study allows first insight into the molecular mechanisms underlining polyphagy in B. tabaci. Our analyses revealed many candidate genes related to the insect's various defense systems capable of neutralizing a broad range of plant toxins. Future technological developments allowing silencing or over-expression of selected target genes in B. tabaci, will enable determining a specific linkage between gene expression and host related performance in this species. 3 hybridizations were performed for RNA extracted from Bemisia tabaci adults that fed on PAP Purple transgenic tobacco plants for 6hr, labeled with Cy5 and directly hybridized against 3 samples from B. tabaci adults that fed on wild type plants as a control and labeled with Cy3. Another 3 swap dye hybridizations were performed in which adults that fed on wild type plants for 6hr were coupled with the Cy5 and adults that fed on PAP Purple transgenic plants were coupled with Cy3.

ORGANISM(S): Bemisia tabaci

SUBMITTER: Michal Alon 

PROVIDER: E-GEOD-31569 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress