Transcriptional regulation of the grape cytochrome P450 monooxygenase gene CYP736B expression in response to <it>Xylella fastidiosa </it>infection

• Main Authors: Walker M Andrew, Takahashi Yuri, Lin Hong, Cheng Davis W, Civerolo Edwin L, Stenger Drake C
• Format: Article
• Language: English
• Published: BMC 2010-07-01
• Series: BMC Plant Biology
• Online Access: http://www.biomedcentral.com/1471-2229/10/135

<p>Abstract</p> <p>Background</p> <p>Plant cytochrome P450 monooxygenases (CYP) mediate synthesis and metabolism of many physiologically important primary and secondary compounds that are related to plant defense against a range of pathogenic microbes and insects. To determine if cytochrome P450 monooxygenases are involved in defense response to <it>Xylella fastidiosa </it>(<it>Xf</it>) infection, we investigated expression and regulatory mechanisms of the cytochrome P450 monooxygenase <it>CYP736B </it>gene in both disease resistant and susceptible grapevines.</p> <p>Results</p> <p>Cloning of genomic DNA and cDNA revealed that the <it>CYP736B </it>gene was composed of two exons and one intron with GT as a donor site and AG as an acceptor site. <it>CYP736B </it>transcript was up-regulated in PD-resistant plants and down-regulated in PD-susceptible plants 6 weeks after <it>Xf </it>inoculation. However, <it>CYP736B </it>expression was very low in stem tissues at all evaluated time points. 5'RACE and 3'RACE sequence analyses revealed that there were three candidate transcription start sites (TSS) in the upstream region and three candidate polyadenylation (PolyA) sites in the downstream region of <it>CYP736B</it>. Usage frequencies of each transcription initiation site and each polyadenylation site varied depending on plant genotype, developmental stage, tissue, and treatment. These results demonstrate that expression of <it>CYP736B </it>is regulated developmentally and in response to <it>Xf </it>infection at both transcriptional and post-transcriptional levels. Multiple transcription start and polyadenylation sites contribute to regulation of <it>CYP736B </it>expression.</p> <p>Conclusions</p> <p>This report provides evidence that the cytochrome P450 monooxygenase <it>CYP736B </it>gene is involved in defense response at a specific stage of <it>Xf </it>infection in grapevines; multiple transcription initiation and polyadenylation sites exist for <it>CYP736B </it>in grapevine; and coordinative and selective use of transcription initiation and polyadenylation sites play an important role in regulation of <it>CYP736B </it>expression during growth, development and response to <it>Xf </it>infection.</p>