Enhancer trapping identifies TRI, an Arabidopsis gene up-regulated by pathogen infection.
Enhancer trap Arabidopsis thaliana plants were screened for genes up-regulated by virus infection. The plants carried T-DNA insertions comprising a minimal -60-bp Cauliflower mosaic virus 35S promoter fused to the beta-glucuronidase (GUS) reporter gene. Approximately 12,000 plants were assayed for GUS activity before and after rub-inoculation with Tobacco rattle virus (TRV) tagged with the green fluorescent protein (GFP). One plant and its progeny consistently showed upregulation of GUS activity in response to TRV-GFP infection, indicating that a virus-responsive enhancer element was "tagged" by the T-DNA in this line. Other viruses, bacteria, and oomycetes, but not wounding, up-regulated GUS activity in the enhancer trap line, indicating that the response was not specific to TRV-GFP infection. A pathogen-inducible, alternatively spliced gene was identified, which we have termed TRI for TRV-induced gene. A pathogen-responsive element was localized to a 1.1-kb region upstream of the T-DNA insertion, and two different cis-acting elements, both implicated in defense responses, were found in the sequence upstream of TRI. Sequence analyses revealed that TRI is similar to ACRE169, a gene that is up-regulated in Cf-9-expressing tobacco when treated with Avr-9, the Cladosporium fulvum elicitor of the Cf-9 resistance response.
Fridborg
Ingela
I
Department of Disease and Stress Biology, John Innes Centre, Norwich, NR4 7UH, U.K.
Williams
Alan
A
Yang
Aidong
A
MacFarlane
Stuart
S
Coutts
Katherine
K
Angell
Susan
S
D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics* / Q000821:virology*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004742:Enhancer Elements, Genetic; D017343:Genes, Plant; D017930:Genes, Reporter; D005966:Glucuronidase / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D010942:Plant Viruses / Q000472:pathogenicity; D011401:Promoter Regions, Genetic; D013045:Species Specificity; D014026:Nicotiana / Q000235:genetics; D015854:Up-Regulation
D004269:DNA, Bacterial; C036483:T-DNA; D005966:Glucuronidase