Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2004
Publication Date: 1/15/2005
Citation: Huang, Y. 2005. Characterization of the defense responses of sorghum plants to greenbug feeding using gene expression profiling approach [abstract]. In: Proceedings of the XIII International Plant & Animal Genome Conference, January 15-19, 2005, San Diego, California. p. 62.
Technical Abstract: Sorghum (Sorghum bicolor), the fifth most important cereal crop grown world-wide, is often attacked by many harmful insects which cause severe crop damage and economic loss. For instance, greenbug (Schiaphis graminum), a phloem-feeding insect, is an important insect pest that attacks several cereal crops including sorghum, barley and wheat. Using sorghum and greenbug as a model, our current studies focus on molecular host-insect interactions. Given a consideration of the case that plants respond to insect attack through a dramatic functional adjustment and re-programming of gene expression, it is believed that a large number of genes are induced in sorghum when it is attacked. In order to understand the molecular details of this interaction, we have used cDNA microarray, a gene expression profiling technology, to identify genes that are either induced or repressed in sorghum seedlings during the host and insect pest interactions. Over 8,200 unique sorghum cDNA clones selected by suppression subtractive hybridization (SSH) were arrayed on glass slides using robotic printing, and then hybridized with fluorescent labeled probes prepared with RNAs from resistant and susceptible lines as well as the RNAs from plants before and during infestation. Comparison of the transcriptional profiles in the parallel assays revealed distinct expression patterns among those assays, reflecting that the resistant and susceptible sorghum plants differentially responded to infestation by virulent greebugs at the molecular level. Thus, a large number of differentially expressed genes were identified by cDNA microarrays. Further their differential expression patterns were confirmed by two validation technologies: northern blotting and real time PCR. Finally, integration of gene expression data into biochemical or metabolic characteristics allowed a logical interpretation of the existing natural resistance mechanisms and facilitated the dissection of the gene regulation pathway to defend against insect attack not only in sorghum plants but also other crop plants.