Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: June 8, 2005
Publication Date: June 12, 2005
Citation: Velten, J.P., Cazzonelli, C.I. 2005. "Crosstalk" of ptgs within agrobacteria-infused leaves is independent of targeted sequence [abstract]. 5th Biennial Meeting on Post-Transcriptional Regulation of Plant Gene Expression, June 8-12, 2005, Austin, Texas. 5:21. Technical Abstract: Post transcriptional gene silencing (PTGS) has been found to play a significant role in both the stability and levels of transgene expression within genetically engineered plants. PTGS was initially manifested as "co-suppression" in transgenic plants and has subsequently been demonstrated in multiple plant species using both transiently expressed and chromosomally located genes. We have made use of two intron-containing luciferase reporter genes, and viral suppressors of gene silencing (HcPro from PVY, p19 from TBSV), to examine the kinetics and characteristics of the version of PTGS occurring within tobacco leaf sections infused with Agrobacteria. This transient expression system displays PTGS similar, if not identical, to that experienced by chromosomally located genes and provides a convenient system for examining the process of PTGS initiation and function. The use of the rapid and sensitive luciferase assays has allowed us to examine the effect(s) of PTGS on different reporter genes in different plant species, and to examine the relationship between PTGS-initiating RNA structure and promoter strength on silencing. One unexpected finding has been the occurrence of "cross talk" between silencing of co-expressed reporter genes, only one of which is directly targeted by in vivo production of dsRNA. This crosstalk results in a "suppression" of silencing of non-targeted reporter genes and appears to be completely sequence independent.