Degree Name

Doctor of Philosophy


School of Biological Sciences


Double-stranded RNA (dsRNA)-induced gene silencing, or RNA interference (RNAi), is a conserved gene control mechanism in eukaryotes that has been exploited extensively as a tool for gene knockdown. In plants, RNAi has been achieved mainly through the expression of transgenes encoding long hairpin-shaped RNA (hpRNA), which has proven to be a powerful tool in gene function studies and crop improvement. A typical hpRNA transgene construct is comprised of a perfect inverted repeat with a sense and antisense sequence of the target gene, separated by a spacer sequence. A number of studies from us and others have indicated that hpRNA transgenes are subject to self-induced transcriptional silencing (self-silencing), compromising the efficiency and long-term stability of RNAi against target genes. We assumed that self-silencing of hpRNA transgenes is due to the perfect invertedrepeat DNA structure and small RNA-directed DNA methylation.

My thesis was aimed at developing and testing new hpRNA transgene designs that could minimize transcriptional self-silencing and give stable and effective target gene silencing...



Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.