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Genetic Loci Controlling Lethal Cell Death in Tomato Caused by Viral Satellite RNA Infection

August 2012 , Volume 25 , Number  8
Pages  1,034 - 1,044

Ping Xu,1 Hua Wang,1 Frank Coker,1 Jun-ying Ma,1 Yuhong Tang,1 Mark Taylor,1 and Marilyn J. Roossinck2

1Plant Biology Division, the Samuel Robert Noble Foundation, Ardmore, OK 73401, U.S.A.; 2Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA 16802, U.S.A.


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Accepted 10 April 2012.

Cucumber mosaic virus (CMV) associated with D satellite RNA (satRNA) causes lethal systemic necrosis (LSN) in tomato (Solanum lycopersicum), which involves programmed cell death. No resistance to this disease has been found in tomato. We obtained a line of wild tomato, S. habrochaitis, with a homogeneous non-lethal response (NLR) to the infection. This line of S. habrochaitis was crossed with tomato to generate F1 plants that survived the infection with NLR, indicating that NLR is a dominant trait. The NLR trait was successfully passed on to the next generation. The phenotype and genotype segregation was analyzed in the first backcross population. The analyses indicate that the NLR trait is determined by quantitative trait loci (QTL). Major QTL associated with the NLR trait were mapped to chromosomes 5 and 12. Results from Northern blot and in situ hybridization analyses revealed that the F1 and S. habrochaitis plants accumulated minus-strand satRNA more slowly than tomato, and fewer vascular cells were infected. In addition, D satRNA-induced LSN in tomato is correlated with higher accumulation of the minus-strand satRNA compared with the accumulation of the minus strand of a non-necrogenic mutant D satRNA.



© 2012 The American Phytopathological Society