A rapid and efficient method to obtain germline gene editing in plants

培育新的改良作物通常涉及鉴定一种带来改良特性的植物基因，例如增加产量或抗病性，然后将该改良基因放入商业种植的作物品种中（通常取代现有的基因）。最近开发的新基因编辑技术（并已成为新闻头条）现在使研究人员能够以非常特定的方式改变植物中现有基因的序列，以便在不需要将外源基因转移到作物中的情况下赋予改良的特性。最常见的是，植物中的这种基因编辑方法涉及遗传转化，因此这些植物被归类为转基因生物。该项目将开发一种替代方法，可以对植物进行精确的基因编辑，从而改善作物，而无需制造转基因植物。与用于治疗某些疾病的医学基因疗法一样，我们将使用病毒（在这种情况下是植物病毒）作为载体，将基因编辑所需的成分导入植物细胞。植物病毒长期以来一直被用于在植物中表达外源基因，例如用于生产疫苗。问题是植物有一种机制，可以将病毒从分生组织中排除出去，而分生组织是植物的一部分，可以继续开花和种子。这对基因编辑来说是个问题，因为它会阻止新的基因改良版本在下一代中遗传。这项研究项目的新奇在于，我们将创建一种能够进入植物分生组织的病毒载体，因此基因编辑将能够在分生组织中发生。这意味着可以收获含有该基因改良版本的种子。通过这种方式，科学家和作物育种家将能够创造大量的基因编辑植物，而不必制造转基因植物。能够使用这种新的病毒载体进行基因编辑的另一个优势是，它能够感染400多个物种，比目前的基因转化多一个数量级，因此，它将大大增加可以通过基因编辑进行改良的作物数量，包括许多在发展中国家种植的作物。

Breeding new improved crops generally involves identifying a plant gene that brings an improved characteristic, for example increased yield or disease resistance, and then putting that improved gene into the crop variety that is grown commercially (often replacing the existing gene that was there). The new gene editing techniques that have recently been developed (and have made news headlines) now enable researchers to change the sequence of an existing gene in a plant in a very specific way so that it confers the improved characteristic without the need to transfer foreign genes into the crop plant. Most commonly such gene editing approaches in plants involve genetic transformation and as a result those plants are classed as GMOs. This project will develop an alternative approach that will enable precise gene editing of plants for crop improvement without the need to make transgenic plants. As with gene therapy, which is used in medicine for treatment of some diseases, we will use a virus (in this case a plant virus) as a vector to get the components needed for gene editing into the plant cell. Plant viruses have long been used to express foreign genes in plants, for example for the production of vaccines. The problem is that plants have a mechanism to exclude viruses from their meristems which are the parts of the plant that go on to make flowers and seed. This is problematic for gene editing as it prevents the new improved version of the gene from being inherited in the next generation.The novelty of this research project is that we will create a virus vector that is able to get into the meristems of plants and so the gene editing will be able to occur in the meristem. This means that seed can be harvested that contains the improved version of the gene. In this way scientists and crop breeders will be able to create a large number of gene edited plants without having to make transgenic plants.Another advantage of being able to use this new virus vector for gene editing is that it is able to infect more than 400 species, an order of magnitude more than can be currently genetically transformed, and so it will greatly expand the number of crops that can be improved by gene editing, including many crops that are grown in developing countries.