Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2008
Publication Date: June 1, 2008
Citation: Cheng, D.W., Lin, H., Walker,, M., Stenger, D.C., Civerolo, E.L. 2008. Transcriptional Regulation of Grape Cytochrome P450 Gene Expression in Response to Xylella fastidiosa. Phytopathology 98:S37. Technical Abstract: Plant cytochrome P450 monooxygenases are versatile redox proteins that mediate biosynthesis of lignins, terpenes, alkaloids, and a variety of other secondary compounds as plant defense agents against a range of pathogens and insects. To determine if cytochrome P450 monooxygenases are involved in the defense response against infection by Xylella fastidiosa (Xf) and its regulatory mechanisms in grapevines, we investigated transcriptional and posttranscriptional modification patterns of a cytochrome P450 gene CYP736B in leaf and stem tissues of PD-resistant and susceptible grape plants after inoculation with this bacterium. Based on genomic DNA and cDNA cloning, the CYP736B gene is composed of two exons and one intron with GT as a donor site and AG as an acceptor site. Gene expression was up-regulated in PD resistant plants and down-regulated in PD-susceptible plants at 6 weeks postinoculation. 5’RACE and 3’ RACE analyses showed that there were 4 major upstream transcriptional regulatory (UTR) regions and 3 major downstream transcription regulatory (DTR) regions. The expression of cytochrome P450 CYP736B gene is regulated in response to Xf infection at both transcription and post-transcription levels. Selective usage of transcriptional initiation sites plays an important role in PD resistant grapevines against Xf infection by affecting transcriptional efficiency, pre-mRNA splicing, and mRNA maturation.