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

该项目的总体目标是开发和测试在大麦减数分裂过程中操纵交叉(CO)形成的频率和分布的策略。控制和操纵CoS以及作物中的基因重组的能力将提高植物育种的速度和效率，这一重要工具在提供21世纪的粮食安全方面可能变得越来越重要。这将对大麦和小麦等作物物种特别有用，在这些物种中，CO事件的高度扭曲分布意味着多达一半的基因几乎不会重组。因此，相当大比例的染色体作为一个大的连锁区块一起遗传，阻止了新基因组合的产生，并随后释放了可在育种计划中利用的有用变异。因此，改变重组事件的分布将释放以前无法获得的遗传多样性。我们已经在模式植物拟南芥中表明，染色质和染色体组织有助于确定CO的分布和频率。此外，我们还证明，通过使用影响染色质缩合的化学物质，我们可以改变CoS在拟南芥中的分布。在这个项目中，将开展一项调查，以确定与拟南芥染色质修饰有关的大麦基因。温和重组的努力将通过开发过度表达或RNAi品系来实现。将通过两种策略来确认操纵大麦重组的尝试：首先，将使用细胞学分析来确定杂交的数量和分布。其次，测试品系将被用来证明由于染色质结构的改变，在确定的遗传区间内重组频率发生了显著变化。

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.