Development of new tools and resources to enhance wheat functional genomics

We propose to improve and exploit recently developed technologies, which utilise defective mismatch repair genes to create a collection of wheat plants containing a high frequency of random mutations that can be screened either by direct sequence analysis or TILLING-based procedures. This collection will be a valuable resource for the UK wheat community, as it would represent a source of new and novel alleles for agronomically important genes. We propose to open up the resource to the entire wheat community as an unencumbered resource free of MTAs and follow on IP agreements. The procedure utilises transgenic technology to create new alleles, however, any novel or useful alleles identified can easily be separated from the transgene by conventional crossing and segregation.

UK wheat breeders are very successful at utilising the available wheat gene pool to select plants with favourable combinations of alleles. However, it is generally accepted that the genetic diversity of commercial wheat is limited as is the hexaploid wheat gene pool in general. Hence, any new source of novel alleles is of considerable interest to wheat breeders. The requirement for such material is likely to become more important to generate both the step change in yield potential required to cope with predicted need and to cope with predicted climate change. Mutations are the ultimate source of all new alleles, however, most mutations and therefore new alleles are either selection neutral or deleterious. Given the deleterious nature of many mutations it is not surprising that the cell has evolved mechanisms to reduce their occurrence such that most mutations never become selectable alleles because they either occur in somatic cells or are removed by the enzymatic process known as mismatch repair (MMR). Given their role in MMR, mutations in the genes encoding the proteins of the MMR system might be expected to have a significant effect on the efficiency of the repair process. This hypothesis has been confirmed in various prokaryote and eukaryote systems. Here we propose to utilise wheat gene constructs to engineer wheat lines defective in MMR. These lines will have an elevated level of mutation above that seen with any previous system and would therefore represent an exciting and novel source of new alleles for wheat developmental geneticists and breeders alike. Given the nature of such a resource it is our intention that the resource would be constructed in a manner amenable to high throughput screening and that it be made freely available to the UK community.