Abstract
BackgroundWhole genome duplication, which results in polyploidy, is a common feature of plant populations and a recurring event in the evolution of flowering plants. Polyploidy can result in changes to gene expression and epigenetic instability. Several epigenetic phenomena, occurring at the transcriptional or post-transcriptional level, have been documented in allopolyploids (polyploids derived from species hybrids) of Arabidopsis thaliana, yet findings in autopolyploids (polyploids derived from the duplication of the genome of a single species) are limited. Here, we tested the hypothesis that an increase in ploidy enhances transgene-induced post-transcriptional gene silencing using autopolyploids of A. thaliana.Methodology/Principal FindingsDiploid and tetraploid individuals of four independent homozygous transgenic lines of A. thaliana transformed with chalcone synthase (CHS) inverted repeat (hairpin) constructs were generated. For each line diploids and tetraploids were compared for efficiency in post-transcriptional silencing of the endogenous CHS gene. The four lines differed substantially in their silencing efficiency. Yet, diploid and tetraploid plants derived from these plants and containing therefore identical transgene insertions showed no difference in the efficiency silencing CHS as assayed by visual scoring, anthocyanin assays and quantification of CHS mRNA.Conclusions/SignificanceOur results in A. thaliana indicated that there is no effect of ploidy level on transgene-induced post-transcriptional gene silencing. Our findings that post-transcriptional mechanisms were equally effective in diploids and tetraploids supports the use of transgene-driven post-transcriptional gene silencing as a useful mechanism to modify gene expression in polyploid species.
Highlights
IntroductionPolyploids, organisms with more than two complete sets of chromosomes, are very common among flowering plants and can derive from a mutation in chromosome number (autopolyploids), or from concurrent hybridization and mutation in chromosome number (allopolyploids) (reviewed in [1] and [2]).Alterations to gene expression and the phenotypic consequences of polyploidy are thought to impact the evolutionary potential of polyploids [3], [1]
Polyploids, organisms with more than two complete sets of chromosomes, are very common among flowering plants and can derive from a mutation in chromosome number, or from concurrent hybridization and mutation in chromosome number.Alterations to gene expression and the phenotypic consequences of polyploidy are thought to impact the evolutionary potential of polyploids [3], [1]
Gene expression changes in Arabidopsis allopolyploids were consistent with a RNA-mediated mechanism, which may play a role in the control of duplicates or homeologous genes in polyploids [7]
Summary
Polyploids, organisms with more than two complete sets of chromosomes, are very common among flowering plants and can derive from a mutation in chromosome number (autopolyploids), or from concurrent hybridization and mutation in chromosome number (allopolyploids) (reviewed in [1] and [2]).Alterations to gene expression and the phenotypic consequences of polyploidy are thought to impact the evolutionary potential of polyploids [3], [1]. Polyploidy has been suggested to affect changes in gene regulation and epigenetic instability [4], [1]. Phenotypic instability and rapid gene silencing, accompanied by DNA methylation re-patterning and transcriptional changes, were found in newly formed Arabidopsis thaliana x Arabidopsis arenosa allopolyploids [5], [6]. Gene expression changes in Arabidopsis allopolyploids were consistent with a RNA-mediated mechanism, which may play a role in the control of duplicates or homeologous genes in polyploids [7]. Polyploidy can result in changes to gene expression and epigenetic instability. Several epigenetic phenomena, occurring at the transcriptional or post-transcriptional level, have been documented in allopolyploids (polyploids derived from species hybrids) of Arabidopsis thaliana, yet findings in autopolyploids (polyploids derived from the duplication of the genome of a single species) are limited. We tested the hypothesis that an increase in ploidy enhances transgene-induced post-transcriptional gene silencing using autopolyploids of A. thaliana
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
