Mol. Plant-Microbe Interact. 5 , 496-503.

Susceptibility and Resistance of Arabidopsis thaliana to Turnip Crinkle Virus

Anne E. Simon(1,2), Xiao Hua Li(3), Jodi E. Lew(1), Rebecca Stange(1), Chunxia Zhang(2), Mary Polacco(1), and Clifford D. Carpenter(1)

(1)Department of Biochemistry and Molecular Biology, (2)Program in Molecular and Cellular Biology, (3)Department of Plant Pathology, University of Massachusetts, Amherst 01003 U.S.A.

The Arabidopsis thaliana ecotype Dijon (Di-0) is resistant to turnip crinkle virus (TCV). It exhibited either no symptoms 3 wk after inoculation or mild symptoms such as stunting, curled bolts, and seliques and early desiccation. Twenty-two other ecotypes of A. thaliana developed a lethal systemic necrosis within 3 wk of inoculation with TCV. Five days after inoculation, TCV genomic RNA accumulated in Di-0 plants, grown under different environmental conditions, at less than 1% of the level found in the susceptible ecotype Col-0. To monitor the accumulation of viral RNA in both inoculated and uninoculated leaves of Col-0 and Di-0, virus-specific probes were hybridized directly to the RNA within whole plants. Results using this procedure revealed that in Col-0 the virus had spread throughout the vascular tissue by 7 days postinoculation. In Di-0, signal was detected mainly in the inoculated leaf and in the opposite leaf of the same age. Di-0 protoplasts, however, were found to support virus replication. These results suggest that restricted virus spread, and not a block in virus replication, is responsible for the resistance of Di-0 to TCV.