Enhanced virus-mediated gene-editing in plant meristematic tissues

For many years it has been possible to manipulate aspects of plant development through the creation of transgenic plants expressing exogenous genes, however it has always been a long-term goal to do this by altering endogenous genes without the need for transgenic plants. Recently technologies have been developed that now enable gene-editing of endogenous genes, such techniques include Zinc finger nucleases, TALENs, and the more recent CRISPR RNA gene editing system. We will use the CRISPR system, to alter the sequences of genes involved in the control of flowering in order to manipulate the flowering time of crop plants.
We have a virus-based expression system which we have already used successfully to express functional proteins in tobacco plants. We will test whether this expression system can be used to deliver the gene-editing proteins/RNA into plant cells and to create gene-edited plants. In this project we will address one of the main constraints of this approach which is to get the virus to express the Cas9 protein and sgRNAs in the shoot apical meristem so that gene editing changes can be made in germ-line cells to produce heritable changes. If such approaches are successful then this will revolutionize the way in which genetically modified plants are produced, enabling them to be produced without the need to incorporate any foreign DNA into their genome.