|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: Caldo, R.A., Nettleton, D., Wise, R.P. 2004. Interplay of non-specific and specific modulation patterns of barley transcriptional responses during powdery mildew infection. Plant and Animal Genome Conference Proceedings. XII Conference. p. 793. Technical Abstract: Large-scale parallel expression analysis was conducted to elucidate Mla-specified responses to powdery mildew infection using 22K Barley1 GeneChip probe arrays. Our goal was to identify genes that are differentially expressed in incompatible (resistant) vs. compatible (susceptible) interactions. 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 containing the Mla1, Mla6, and Mla13 resistance specificities in response to inoculation with the Blumeria graminis f. sp. hordei (Bgh) isolates 5874 (AvrMla1, AvrMla6) and K1 (AvrMla1, AvrMla13). F-tests associated with specific contrasts were used as part of a mixed linear model analysis to identify genes whose transcriptional pattern differed significantly over the course of powdery mildew infection. Twenty-two genes, of which half were unknown function, showed 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 are correlated with general conidiospore germination and appressorial growth prior to 16 hai, in addition to the onset of Mla-specified resistance that occurs after attempted penetration of epidermal cells in incompatible interactions. Based on the microarray data, we propose a model for the interplay of non-specific and specific recognition of powdery mildew invasion in modulating barley transcriptional responses. Research supported by USDA-IFAFS grant no. 2001-52100-11346.