Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: December 9, 2009
Publication Date: January 9, 2010
Citation: Weng, Y., Bai, J., Akhunova, A., Azhaguvel, P., Rudd, J. 2010. Expression Profiling of R Gene-Mediated Host Defense Against Aphid Feeding in Wheat [abstract]. Plant and Animal Genome Conference. p. 232.
The greenbug, Schizaphis graminum (Rondani), is an important aphid pest of wheat in the southern High Plains of the U.S. The single dominant gene, Gb3 confers consistent and durable resistance against prevailing greenbug biotypes in wheat fields. However, molecular mechanisms of R gene mediated host resistance against aphid pests in cereal crops are not well understood. In a two-genotype, three-time-point (0, 24 and 48 hours after infestation with biotype E greenbugs, hai), and three-replicate expression profiling experiment with Affymetrix wheat GeneChips, Gb3-mediated host defense against greenbug feeding was investigated. The R and S super pools were respectively composed of eight homozygous resistant or eight susceptible F7 recombinant inbred lines (RILs) (3 plants per RILs) derived from a cross between two near isogenic lines of Gb3. Of the 55K transcripts surveyed, 47 showed significant differences in constitutive expression between the R and S pools (P = 0.05). Statistical analysis identified 760 genes with significant changes (P = 0.05) in expression levels between R and S pools at one or more time points before and or infestation. Expression patterns of selected genes were validated with quantitative real-time PCR, which were highly consistent with microarray data. While R gene-mediated defense shared many pathways with basal defense, most up-regulated genes in resistant genotype were defense and defense signaling related and most up-regulated genes in susceptible genotype were involved in reprogramming of metabolic pathways. The Gb3-mediated host resistance seems to be able to prevent the aphids from manipulating host plant’s metabolic pathways to their favor.