Maize Artificial Chromosomes

本课题的总体目标是研究植物人工染色体技术。人工染色体有可能将对农业和基础植物基因组学研究有益的基因堆叠在一条独立的染色体上。将新基因添加到已有的人工染色体平台的程序将被开发出来，可以继续永久地进行修改。其次，将测试允许在单个增量中向小染色体添加比目前可能的更多数量的基因的方法。第三，将人工染色体与单倍体育种相结合，更有效地将小染色体引入多个新品种。第四，进行花粉选择试验，最大限度地使人工染色体从一代传给下一代。人工或工程化的小染色体有可能提供一个预先确定的转基因整合到植物基因组中的位点，而不是目前使用的植物转化的随机性。靶向插入将避免潜在的诱变效应和基因沉默，这通常是由不受控制的整合引起的。此外，现在存在这样一种可能性，即决定几种植物特性的许多不同基因可以同时转化到一个小染色体上，这个小染色体可以进一步修饰，并且独立于正常染色体。利用人工染色体，应该可以引入完整的生化途径，为植物添加新的特性，从而促进最终产量的最大化，或者将植物作为廉价生产有用蛋白质或代谢物的工厂。在基础研究方面，人工染色体为生成符合规范的染色体提供了手段，为染色体行为和基因表达等学科的研究提供了便利。一段时间以来，地球上可耕地的数量一直保持不变，但全球人口却在不断增加。如果世界的生活水平保持不变或有所提高，在未来几十年里，农业生产的粮食数量将需要增加。解决这个问题需要许多新的发展，但操纵植物基因组的新方法被认为是这一努力的主要贡献者。植物人工染色体平台的开发和增强可能有助于解决这一问题。所开发的程序应易于适用于其他植物物种，因此可以作为向它们转移的示范系统。培训将涉及植物基因组学和生物技术方面的本科生和研究生。有关该项目及其成果的信息可以在项目网站（http://maizeminichromosomes.missouri.edu）和MaizeGDB上访问。其中包括关于项目目标、结果、参与者、出版物以及产生的生物资源（如病媒和玉米品系）和用于产生它们的方案的详细信息。此外，还可以通过该项目网站MaizeGDB和ResearchGate （http://www.researchgate.net/）访问演示该项目所涉及技术的YouTube视频链接。

The overall goal of this project is to artificial chromosome technology in plants. Artificial chromosomes have the potential to stack genes of benefit to agriculture and basic plant genomics studies on an independent chromosome that can be made to specification. Procedures to add new genes to pre-existing artificial chromosome platforms will be developed that can continue to make amendments in perpetuity. Secondly, methods will be tested that allow much larger numbers of genes to be added to a minichromosome in a single increment than is currently possible. Thirdly, the combination of artificial chromosomes with haploid breeding to introduce the minichromosomes into multiple new varieties more efficiently will be developed. Fourthly, a test of pollen selection to maximize the transmission of artificial chromosomes from one generation to the next will be conducted. Artificial or engineered minichromosomes have the potential to provide a pre-determined site of transgene integration into a plant genome rather than the random nature of plant transformation that is currently used. The targeted insertion will avoid the potential mutagenic effect and gene silencing that often results from uncontrolled integrations. Moreover, the potential now exists that many different genes determining several plant characteristics can be transformed at once onto a minichromosome that can be further modified and that is independent of the normal chromosomes. With the use of artificial chromosomes it should be possible to introduce whole biochemical pathways to add new properties to plants that would facilitate maximizing the ultimate yield or to use plants as factories for the inexpensive production of useful proteins or metabolites. For basic studies, artificial chromosomes provide the means to generate chromosomes to specification that will facilitate the study of chromosome behavior and gene expression among other subjects.The amount of arable land on earth has been static for some time but the global population continues to increase. If the world standard of living is to remain as is or improve, the amount of food produced by agricultural endeavors will need to increase over the coming decades. Many new developments will be needed to address this issue but novel means of manipulating plant genomes is thought to be a major contributor to this effort. The development of plant artificial chromosome platforms and their enhancement might help with this problem. The procedures developed should be easily adapted to other plant species and thus can serve as a model system for transfer to them. Training will involve diverse undergraduate and graduate students in plant genomics and biotechnology. Information about this project and its outcomes can be accessed at the project website (http://maizeminichromosomes.missouri.edu) and MaizeGDB. These include detailed information about project objectives, results, participants, publications as well as biological resources produced such as vectors and maize lines and the protocols used to generate them. In addition, links to YouTube videos illustrating the techniques involved in the project will be accessible through the project website, MaizeGDB and ResearchGate (http://www.researchgate.net/).