Perez, Kari , Kang, Byoung-Cheorl , Yeam, Inhwa , Jahn, Molly .
The VPg of tobacco etch virus is the virulence determinant for recessive resistance gene pvr1 in Capsicum.
Broad spectrum potyvirus resistance in Capsicum has been attributed to point mutations at the pvr1 locus which are predicted to result in conformational shifts in its encoded protein eukaryotic translation initiation factor eIF4E. There are three pvr1 alleles which confer potyvirus resistance; pvr1, pvr11 and pvr12 all showing recessive inheritance. These mutations prevent interaction with VPg, the viral protein attached to the 5’ end of the potyvirus genome both in vitro and in planta. VPg has been found to be critical for virus-host interaction spanning a broad host range including the interaction of Capsicum with Tobacco etch virus (TEV), where interaction has been correlated with infectivity. In this study, the VPg domains of three TEV strains, TEV HAT, Mex21 and N, which differentially infect Capsicum lines encoding pvr1, pvr11 and pvr12 were compared. To determine if VPg is the virulence determinant in this pathosystem, two VPg viral chimeras were synthesized. An infectious cDNA clone of the TEV-HAT genome which also encoded GFP was used as a template. The VPg domain of non-infectious TEV-HAT was replaced with that of TEV-Mex21 and TEV N, two stains which can infect pvr1 and pvr12, respectively. Substituting VPg from an infectious TEV strain resulted in infection in both homozygous pvr1 and pvr12 hosts. Infection was monitored both by ELISA and GFP accumulation. Additionally, the domain of TEV-HAT VPg essential for interaction with susceptible allele Pvr1 was determined within 20 amino acids via yeast 2-hybrid analysis.
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1 - Cornell University, Plant Breeding and Genetics, Jahn Lab - 306 Bradfield Hall, Ithaca, NY, 14853, USA
2 - Seoul National University, College of Agriculture and Life Sciences, Dept. of Plant Science
3 - Cornell University, Department of Plant Breeding and Genetics
4 - University of Wisconsin-Madison, College of Agricultural and Life Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM