Submitted to: Keystone Symposia
Publication Type: Abstract Only
Publication Acceptance Date: April 14, 2004
Publication Date: July 8, 2004
Citation: Velten, J.P., Cazzonelli, C.I. 2004. Characteristics of gene silencing during transient expression in tobacco leaves infused with agrobacteria. Keystone Symposia. Technical Abstract: Post transcriptional gene silencing (PTGS) has been found to play a significant role in the both the degree and location of expression, as well as expression stability, of new genes introduced into plants during the process of genetic engineering. PTGS has been demonstrated using both transiently expressed and stably integrated transgenes in several plant species. Recent developments have shed significant light on many of the cellular components and mechanisms contributing to PTGS, however, exactly how and why specific genes and transcripts are targeted for silencing remains largely a mystery. We have made use of two intron-containing luciferase reporter genes, and a viral suppressor of gene silencing, to examine the kinetics and characteristics of the version of PTGS that occurs within tobacco leaf sections infused with Agrobacteria. This transient expression system has been clearly demonstrated to be subject to PTGS similar, if not identical, to that experienced by stably integrated genes and provides a convenient system for examining the process of PTGS initiation. The high sensitivity of the luciferase assays has allowed us to observe the development of PTGS early in the process of initiating transient reporter gene expression and to examine the relationship between promoter strength and PTGS across a broad range of promoter strenghts.