Submitted to: Molecular Plant Microbe International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2001
Publication Date: N/A
Technical Abstract: When Columbia Arabidopsis plants (Col-0) are infected by Tobacco ring spot virus (TRSV), they display no obvious symptoms. In contrast, Estland Arabidopsis plants become systemically necrotic and die within two weeks of inoculation. Previous genetic studies revealed that symptom expression is controlled by a single semidominant gene, TTR1. The gene was mapped to an interval of approximately 80-kb on chromosome V. Using the sequence for this region, DNA fragments representing predicted genes and flanking regions were analyzed in reciprocal transformation-complementation tests. In preliminary studies, two Col-0 lines transformed with a 6.7-kb fragment of Eastland genomic DNA developed systemic necrosis upon TRSV infection. Analysis of T-DNA insertion region indicates that a Col-0 line has a T-DNA in the gene encoding 155-kDa disease resistant-like protein. The predicted amino acid sequence of the protein showed significant similarity to the sequences of TIR-NBS-LRR resistant gene products, including those of RPS4, L6, and N, which are responsible for hypersensitive resistance to bacterial, fungal, and viral pathogens, respectively. In addition, the protein also contains a WRKY-domain in its C-terminus. These data suggest that Col-0 tolerates TRSV infection conditioned by a TIR-NBS-LRR-WRKY gene, and further suggest that disease sensitivity in Estland may be due to the nonfunctional allele of the TIR-NBS-LRR-WRKY gene.