Highly efficient, 5′-sequence-specific transgene silencing in a complex polyploid

Sugarcane, a complex polyploid, shows highly efficient and rapidly imposed silencing of diverse transgene constructs. Silencing is 5′-sequence-specific, copy-number independent, developmentally regulated and post-transcriptional in the plants first regenerated from transgenic callus. The results challenge some early generalizations from studies in model dicotyledonous plants, about causes of transgene silencing and approaches to avoid the problem. We reason that patchy and progressive transgene silencing, seen in most other plant species, may be associated with increasing endopolyploidy during maturation of differentiated tissues. The experimentally tractable sugarcane system allows features likely to trigger or protect from silencing to be tested, and ultimately controlled to improve the efficiency of plant improvement by genetic transformation. © 2010 Springer Science+Business Media, LLC.