description
- Many plant species are polyploid, which means that all their DNA has been duplicated and they have multiple copies of each gene in each cell. Having multiple copies of each gene can give polyploid plants more options for gene function due to different combinations of gene expression; this complex orchestration may improve mechanisms for plant resilience and adaptation. However, how this happens at the molecular level is not well understood. In our lab we are using hexaploid wheat as an example to start understanding the multiple copies of genes in polyploids. Wheat is a useful polyploid model system because we have a fully sequenced genome and other high-quality resources for research. The different organs in a wheat plant all have the same DNA with three copies of each gene, but the gene copies can be switched on or switched off independently. We call the degree to which a gene is switched on its expression level (i.e. gene switches can act like dimmer switches). We recently found that gene copies are switched on (expressed) at different levels in different organs. For example in a leaf copy number 1 might be highly expressed, but in the roots copy number 1 is reduced in expression and copy number 2 is highly expressed instead. In diploid plants such as the model species Arabidopsis, individual cell types have different expression levels and there are differences in expression between cells of the same type. We hypothesise that these cell-level differences will also occur in polyploid wheat including between gene copies, which will add an additional level of transcriptional flexibility for polyploid species with may underpin their high environmental adaptability and vigour.