Manipulating the frequency and distribution of genetic crossovers during meiosis in barley

The overall aim of the proposed project is to develop and test strategies for manipulating the frequency and distribution of crossover (CO) formation during meiosis in barley. The ability to control and manipulate COs and consequently genetic recombination in crop plants will improve the speed and efficiency of plant breeding, an important tool that is likely be increasingly important in providing food security for the 21st century. This would be particularly useful for crop species such as barley and wheat where a highly skewed distribution of CO events means that up to half of the genes rarely if ever recombine. As a consequence a substantial proportion of the chromosomes are inherited together as a large linkage block, preventing the generation of novel gene combinations and subsequently the release of useful variation that could be exploited in breeding programs. Thus changing the distribution of recombination events would release previously inaccessible genetic diversity. We have already shown in the model plant, Arabidopsis that chromatin and chromosome organization contribute to the determination of CO distribution and frequency. Further we have also demonstrated that by using chemicals that affect chromatin condensation we can alter the distribution of COs in Arabidopsis. In this project, a survey will be carried out to identify barley genes that have been implicated in chromatin modification in Arabidopsis. Efforts to moderate recombination will be either by developing overexpressing or RNAi lines. Confirmation of the attempts to manipulate recombination in barley will be by using two strategies: Firstly, cytological analysis will be used to determine the number and distribution of crossovers. Secondly, test lines will be made and used for the demonstration of a significant change in recombination frequency in defined genetic intervals as a result of the modifcation in chromatin organization.