A forward genetic screen to identify genes involved in the maintenance of organelle genome stability in Arabidopsis thaliana.

众所周知，遗传不稳定会导致许多人类疾病，如癌症和神经退行性疾病。在植物中，突变也可以破坏基因组的稳定，当发生在细胞器基因组(叶绿体和线粒体)中时，会导致表型变异，如细胞质雄性不育(植物不能脱落花粉)、杂色(植物具有白色和绿色的叶子)和耐热性。尽管这些表型可能提供新的、重要的农业性状，但产生相关突变的机制仍然难以捉摸。在这里，我们建议评估参与维持遗传稳定性的基因在拟南芥细胞器中的作用，拟南芥是植物遗传学研究的模式生物。这将通过收集5万多种植物来实现，每种植物都缺乏一种特定的基因。这项研究中采用的方法是将植物播种在含有诱变剂的生长介质上，以刺激植物细胞器中的DNA不稳定。我们假设，缺失了与维持遗传稳定性有关的基因的植物将对这种处理更加敏感。之后，将有可能对植物细胞器不同DNA代谢途径中识别的基因进行分类，如DNA复制和修复。我们的工作已经确定了与这些途径有关的几个基因，进一步的特征正在进行中。作为我们研究的后续步骤，确认在拟南芥中发现的基因是否在作物中发挥类似的作用将是有趣的。事实上，促进突变性状的产生有很大的农业利益，例如细胞质雄性不育(用于杂交生产)、抗热性和作物植株的多样性。

Genetic instability is well known to induce many human pathologies such as cancer and neurodegenerative diseases. In plants, mutations can also destabilize genomes and, when occurring in organellar genomes (chloroplast and mitochondria) lead to phenotypic variations such as cytoplasmic male sterility (plant unable to shed pollen), variegation (plant with white and green leaves) and resistance to heat. Although these phenotypes may provide new, important agricultural traits, the mechanisms generating the related mutations remain elusive. Here we propose to evaluate the role of the genes involved in the maintenance of genetic stability in the organelles of Arabidopsis thaliana, the model organism for plant genetics studies. This will be achieved using a collection of more than 50,000 plants, each of them depleted for a particular gene. The methodology applied in this study will be to sow the plants on a growth medium containing a mutagenic agent to stimulate DNA instability in plants organelle. We hypothesize that plants depleted of a gene implicated in the maintenance of genetic stability will be more sensitive to such treatment. Afterwards, it will be possible to classify the genes identified in the different DNA metabolism pathways of plant organelle such as DNA replication and repair. Our work has already identified several genes involved in these pathways and further characterisation is underway. As a subsequent step in our study, it will be interesting to confirm whether the genes identified in Arabidopsis play a similar role in crops. Indeed, there is great agricultural interest to facilitate the production of mutant traits such as cytoplasmic male sterility (used for hybrid production), resistance to heat and variegation in crop plants.