Increasing genetic diversity in wheat by interfering with mismatch repair

错配修复（MMR）是所有生物体用来修复DNA损伤的过程。我们打算培育具有较低MMR水平的小麦植株，从而提高遗传多样性和重组水平。作为原理证明，我们打算使用这种材料来产生携带hmw -谷蛋白等位基因新组合的细胞系。对小麦遗传学家和小麦育种家来说，具有更大等位基因多样性的植物既是新等位基因的来源，也是染色体重组产生新变体的手段，具有极大的价值。该方法建立在我们现有的工作基础上，使用截断的小麦减数分裂后分离增加2 （TaPMS2）基因来降低错配修复活性（MMR）。在本提案中，我们打算开发和鉴定一系列携带单基因和多基因结构的转基因系，以进一步降低MMR活性。我们假设这样的植物将携带更高水平的等位基因多样性，例如在谷蛋白位点内，我们还假设MMR活性降低将导致植物在不相同序列之间具有更高水平的重组。由于这种转基因材料对今天的小麦育种者来说可能是有问题的，我们也打算寻求替代的，但长期的，通过非转基因手段产生类似材料的途径。

Mismatch repair (MMR) is the process which all organisms use to repair DNA damage. We intend to generate wheat plants which have reduced levels of MMR and hence elevated levels of genetic diversity and recombination. As a proof of principle we intend to use this material to generate lines carrying novel combinations of HMW-glutenin alleles. Plants having greater allele diversity will be extremely valuable to wheat geneticists and wheat breeders as both a source of new alleles and as a means of recombining chromosomes to generate new variants. The approach builds upon our existing work using a truncated wheat Post Meiotic Segregation Increased 2 (TaPMS2) gene to reduce mismatch repair activity (MMR). In this proposal we intend to develop and characterise a series of transgenic lines carrying single and multiple gene constructs to further reduce MMR activity. We hypothesize that such plants will carry an increased level of allelic diversity, for instance within the glutenin loci, we also hypothesize that reduced MMR activity will lead to plants having a higher level of recombination between non-identical sequences. As such transgenic material might be problematical for today's wheat breeders, we also intend to pursue alternative, but longer term, routes to generate similar material via non-transgenic means.