|Caldo, Rico - IOWA STATE UNIVERSITY|
|Nettleton, Dan - IOWA STATE UNIVERSITY|
Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 10, 2004
Publication Date: January 10, 2004
Citation: Wise, R.P., Caldo, R.A., Nettleton, D.A. 2004. Parallel expression profiling of gene-for-gene-specified responses in barley-powdery mildew interactions.Plant and Animal Genome XII Conference. p. W33. Technical Abstract: The barley/powdery mildew pathosystem is an ideal model for the investigation of gene-for-gene interactions among cereal crops and obligate fungal biotrophs. Large-scale parallel expression analysis was conducted to identify genes that are differentially expressed in incompatible (resistant) vs. compatible (susceptible) interactions using 22K Barley1 GeneChip probe arrays. A split-split-plot design with 108 experimental units (3 replications x 2 isolates x 3 genotypes x 6 time points) was used to profile near-isogenic lines harboring the Mla1, Mla6, and Mla13 CC-NBS-LRR resistance genes in response to inoculation with the Blumeria graminis f. sp. hordei isolates 5874 (AvrMla1, AvrMla6) and K1 (AvrMla1, AvrMla13). A mixed linear model analysis was conducted for each of the 22,840 probe sets using the SAS mixed procedure. F-tests associated with specific contrasts were used to identify genes whose transcriptional pattern differed significantly (p=0.0001) over the course of powdery mildew infection. Twenty-two genes, which half were of unknown function, revealed highly similar patterns at the very early time points of infection, but were markedly different at 16 to 32 hours after inoculation (hai). These transcriptional responses correlate with general conidiospore germination and appressorial growth prior to 16 hai, in addition to the onset of incompatibility that occurs after attempted penetration of epidermal cells. Research supported by USDA-IFAFS grant no. 2001-52100-11346 and the North American Barley Genome Project.