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

培育新的改良作物通常包括识别一种能带来改良特性的植物基因，例如提高产量或抗病能力，然后将改良基因植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，以便在不需要将外来基因转移到农作物中的情况下，赋予其改进的特征。在植物中，最常见的基因编辑方法涉及基因转化，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，使植物的精确基因编辑能够用于作物改良，而不需要制造转基因植物。与用于治疗某些疾病的医学上的基因疗法一样，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带入植物细胞。长期以来，植物病毒一直被用来在植物中表达外源基因，例如用于生产疫苗。问题是，植物有一种从分生组织中排除病毒的机制，分生组织是植物中继续开花和结籽的部分。这对于基因编辑来说是有问题的，因为它阻止了新的改进版本的基因在下一代被遗传。这个研究项目的新奇之处在于，我们将创造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，科学家和作物育种者将能够创造大量的基因编辑植物，而不必制造转基因植物。使用这种新的病毒载体进行基因编辑的另一个好处是，它能够感染400多种物种，比目前可以遗传转化的物种多一个数量级，因此它将极大地扩大可以通过基因编辑改良的作物的数量，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.