Lopez-Ochoa, Luisa , Hanley-Bowdoin, Linda .
Use of peptide aptamers for broad-based geminivirus disease resistance.
Peptide aptamers are recombinant proteins that bind to and inactivate the target protein. They can bind to eukaryotic targets in cellular and whole organism systems and are especially attractive as antivirals. Geminiviruses are single-stranded DNA viruses that infect important crops worldwide. They often occur as mixed infections in the field, and synergy and recombination among different viral species can result in increased pathogenicity and rapid evolution. Thus, it is essential to develop a strategy that confers broad-based, stable resistance. We used a combinatorial chemistry approach to target the N-terminus of the Tomato golden mosaic virus (TGMV) Rep protein. This region contains motifs that mediate origin recognition and DNA cleavage during initiation of viral replication and are highly conserved among single-stranded DNA viruses. A yeast two-hybrid screen of a random peptide library identified 88 peptide aptamers that bind to the N-terminus of the TGMV Rep protein, 31 of which reduced TGMV DNA accumulation to 13-64% of wild type in transient replication assays. These aptamers also bind to Rep proteins from other geminiviruses, including Cabbage leaf curl virus (CaLCuV), Beet curly top virus (BCTV), East African cassava mosaic virus-Uganda and African cassava mosaic virus–Cameroon. Based on their breadth and strength of interaction, expression cassettes corresponding to 12 aptamers were stably introduced into Arabidopsis. Preliminary experiments of plants infected with CaLCuV and BCTV showed either a delayed in symptom development or a recovery phenotype. This promising result suggests that this technology may be useful in conferring resistance to more than one geminivirus. Results of infectivity assays with homozygous transgenic plants will be presented.
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1 - North Carolina State University, Molecular and Structural Biochemistry, Biochemistr. Campus Box 7622, North Carolina State University, Raleigh, NC, 7695-7622, USA
2 - North Carolina State University, Molecular and Structural Biochemistry
broad based resistance
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM