Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: January 9, 2010
Publication Date: January 9, 2010
Citation: Okubara, P.A. 2010. Defense gene expression profiling of a wheat-Pseudomonas biocontrol interaction. Annual International Plant & Animal Genome Conference. San Diego, CA, January 9-13, 2010, Abstract W442. Technical Abstract: In wheat (Triticum aestivum), specific root-colonizing strains of the bacterium P. fluorescens confer protection against soilborne fungal pathogens, but their role in inducing host defense responses is not fully known. To address this information gap, we sorted and annotated over 16,745 root-expressed sequence tags (ESTs) generated by the NSF Wheat EST Genomics Project. A 192-feature oligonucleotide microarray was constructed from 86 wheat root homologues of defense/stress genes from Arabidopsis, tomato, rice, and barley. Microarrays were interrogated with Alexa Fluor 546-labeled transcript (cDNA) populations from roots or coleoptiles of cultivar Finley and near-isogenic vrn1A lines 442 and 443 four days after seed inoculation with the aggressive biocontrol strain P. fluorescens Q8r1-96. Transcripts encoding Ca2+-dependent protein kinases, and oxidative stress, cold stress and jasmonic acid pathway components were increased two-fold or more in roots during P. fluorescens interactions. Transcripts for HR-induced polypeptides and PR-10a were induced in both roots and coleoptiles. Induction of eleven transcripts, including DHAR, MDAR, COI1 and PR-10a, was observed within six hours of inoculation using quantitative real-time reverse-transcription PCR. Our findings suggest that biocontrol P. fluorescens modulates multiple stress pathways in wheat roots and coleoptiles.