Submitted to: Genomics
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2007
Publication Date: 12/1/2007
Citation: Coram, T., Settles, M.L., Lin, F., Wang, M.N., Chen, X. 2007. Transcriptome analysis of high-temperature adult-plant resistance conditioned by Yr39 during the wheat-Puccinia striiformis f. sp. tritici interaction. Natl WHeat Genomics Conference, Dec 1-2, Kansas City, MO. Pg 27.
Technical Abstract: Stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici Eriks. (Pst)) is a destructive disease of wheat (Triticum aestivum L.) worldwide. High-temperature adult-plant resistance (HTAP) to stripe rust is non-race-specific, inherited quantitatively, and is often more durable than race-specific resistance. Previously, we identified and mapped the single Yr39 HTAP stripe rust resistance gene in the spring wheat cultivar Alpowa, which was identified on chromosome 7BL and accounted for 64.2% of the variation in HTAP resistance. To identify transcripts associated with Yr39-mediated HTAP resistance, we selected two recombinant inbred lines from an ‘Avocet S/Alpowa’ cross that differed at the Yr39 locus to represent an incompatible (Yr39) and compatible (yr39) interaction with Pst. Using the Affymetrix Wheat GeneChip, we profiled the transcription changes occurring in flag leaves of these two lines over a time-course after treatment with Pst urediniospores and mock-inoculation. This time-course study identified 207 and 8 transcripts that were significantly induced and repressed during Yr39-mediated HTAP resistance, respectively. Only one unknown transcript was induced during the compatible interaction. The temporal pattern of transcript accumulation showed a peak at 48 h after infection, which was supported by quantitative PCR assays that showed a rapid increase in fungal biomass after this time in the compatible interaction. Most (64%) of the annotated transcripts specifically induced during HTAP resistance were involved in defense and/or signal transduction, including transcripts associated with pathogenesis-related protein production, phenylpropanoid (lignin) and anthocyanin biosynthesis, and receptor-protein-kinase signaling. As expected for non-race-specific resistance, few transcripts associated with an oxidative burst and/or hypersensitive response were identified. This study represents the first transcript profiling of HTAP resistance to stripe rust in wheat, and we conclude that Yr39-mediated HTAP resistance involves substantial gene expression changes associated with known non-specific defense mechanisms.