Poster: Plant-pathogen interactions

Abs # 559: Random peptides that interact with Geminiviruses Rep proteins

Presenter:	Lopez-Ochoa, Luisa A., laochoa@unity.ncsu.edu
Authors	Lopez-Ochoa, Luisa A. (A)   Nash, Tara  (A)   Hanley-Bowdoin, Linda  (A)
Affiliations:	(A): North Carolina State University

Over the past decade, geminiviruses have emerged as leading plant pathogens that cause severe crop losses worldwide. Because they are evolving rapidly and frequently occur as mixed infections in the field, it is essential to develop broad-based resistance. To address this need, we have designed an interfering peptide strategy based on the viral replication protein (Rep), which is highly conserved among geminiviruses and other single-stranded DNA viruses. The N-terminus of Rep contains several conserved motifs required for origin recognition and DNA cleavage/ligation during rolling circle replication. We used the the N-terminus of the Rep protein from Tomato Golden Mosaic Virus (TGMV) as bait, to screen a constrained random peptide library in a yeast two-hybrid system. This screen selected nearly 100 unique peptides that bind to TGMV Rep. These peptides group in 8 different clusters based on sequence homology. We developed a semi-quantitative PCR protocol to facilitate high throughput screening for replication interference in transient assays. To date, this assay has verified that 10 % of the interacting peptides interfere with TGMV replication. Experiments are in progress to determine the breadth of the binding and interference activities against other geminiviruses.