Map-based cloning and characterization of a QTL (quantitative trait loci) network underlying growth responses to drought in Arabidopsis thaliana

由于干旱在世界范围内造成农作物严重的产量损失，培育耐旱性更强的品种是当今植物育种的主要目标。尽管基因工程已经培育出了能够在严重干旱中存活的作物，但到目前为止，人们还没有注意到培育出在中度缺水情况下具有稳定生长和生产力的植物的必要性。已有研究表明，模式植物拟南芥具有广泛的自然等位基因变异，可以利用数量遗传学工具对轻度干旱胁迫进行耐受性研究。在我们以前的工作中，我们检测并验证了一个QTL(数量性状基因座)网络，该网络控制拟南芥对轻度水分亏缺的生长反应。未来项目的目标是确定这个网络背后的基因和功能多态。为了做到这一点，定位克隆方法将与基因表达分析相结合。此外，我们打算澄清低生长反应是否与对水分亏缺的生理调节有关，是否我们能检测到干旱和其他影响植物水分状况的非生物胁迫之间的相互作用，以及是否存在干旱适应的区域模式。我们预计，在未来，所获得的知识将特别有助于培育受轻度干旱胁迫影响较小的油菜品种的标记。

As drought causes severe yield losses in crop plants worldwide, developing varieties with increased drought tolerance is nowadays a major goal of plant breeding. Although crop plants which are able to survive severe drought have been created by genetic engineering, the need to develop plants with stable growth and productivity when subjected to moderate water deficit has poorly gained attention so far. It has been shown that the model species Arabidopsis thaliana provides extensive natural allelic variation for tolerance to mild drought stress which can be exploited using quantitative genetics tools. In our previous work, we detected and validated a QTL (quantitative trait loci) network which controls growth responses to mild water deficit in Arabidopsis. The aim of the future project is to identify the genes and functional polymorphisms underlying this network. To do so, a positional cloning approach will be combined with gene expression analyses. Furthermore, we intend to clarify if a low growth response is associated with physiological adjustments to water deficit, if we can detect cross-talk between drought and other abiotic stresses affecting plant water status, and if there exists a regional pattern of drought adaptation in A. thaliana. We expect that in the future the knowledge achieved could facilitate in particular the development of markers for breeding rapeseed cultivars less affected by mild drought stress.