Submitted to: Insect-Plant Relationships International Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2004
Publication Date: August 7, 2004
Citation: Huang, Y. 2004. Gene expression patterns in greenbug resistant and susceptible sorghum in response to attack by Schizaphis graminum [abstract]. In: Proceedings of the 12th Symposium Insect-Plant Relationships, Berlin, Germany. p. 51. Technical Abstract: Sorghum, the fifth most important cereal crop grown worldwide, is host to nearly 150 insect species, some of which cause severe crop damage and economic loss. To explore the genetic mechanisms that underlie plant defense against insect pests, for example the greenbug, it is necessary to identify and characterize the genes that respond to feeding by the insect. Plants respond to cell content-feeding insects with dramatic functional adjustment and reorganization that involve the activation of direct and indirect defense and tolerance. We used the high through-put DNA microarray technology to analyze expression patterns of sorghum cDNA clones generated by suppression subtractive hybridization. This approach revealed very different transcript profiles between resistant and susceptible sorghum genotypes which were subjected to simultaneous infestation by greenbugs. Among the large number of differentially expressed genes, more than 50% of the infestation-inducible genes were rarely transcribed in uninfested plants, and over one-fourth of the genes have not been identified in the genebank databases. Apparently, transcripts involved in photosynthesis were strongly down-regulated in the susceptible line, whereas genes associated with other defense pathways, like disease response pathways, were up-regulated in the resistant line. Indeed, some of these induced genes appear to be similar to those activated in plants against pathogens. Changes of transcriptional profiles in the resistance line indicate the existence of natural mechanisms in the genome of resistant plants. The resultant cDNA collection may contribute to our understanding of genetic mechanisms of plant resistance to insect pests.