Antisense RNA, meiosis and phytohormones in the model fungal plant pathogen Ustilago maydis

植物真菌病是造成世界粮食危机的一个主要因素。在加拿大，每年因叶锈菌对小麦作物造成的损失可达1亿美元。锈菌只能在植物中生长，很难处理。相比之下，相关的玉米黑穗病真菌麦氏菌（Ustilago maydis）很容易生长，并有详细的研究方案。因此，虽然这种真菌对玉米作物造成严重损害，因此必须加以了解，但它也可以作为了解所有锈病和黑穗病的模型。在我上一笔NSERC拨款中，我们通过基因组分析进一步开发了黑穗病真菌的模型。这为研究提供了更好的工具，并能够将我们获得的知识转移到其他真菌上。我们现在处于一个非常有利的位置，可以利用这些工具来研究三个领域：1)通过反义RNA表达控制基因表达；2)有性生殖的控制；3)真菌产生植物激素。Fire和Mellow因发现基因表达的反义控制而获得了2006年的诺贝尔奖。虽然他们描述的系统在大多数生物体中起作用，但玉米黑穗病真菌有一种不同的方式通过反义控制基因表达。我们会用申请的资金弄清楚那是什么。真菌病原体的有性繁殖会打乱毒力基因，并可能导致更致命的疾病。我们项目2的目标是了解性是如何被控制的，以及与寄主植物的相互作用是如何导致黑穗病真菌有性繁殖的。在项目3中，我与特伦特大学的另一位教授合作，确定黑穗病真菌在感染期间如何改变玉米植株。我们有证据表明这种真菌是通过植物激素来做到这一点的，我们需要资金来研究它是如何做到的。我们从其他资金来源获得了购买设备的资金，所以这里申请的资金，是用来支持学生在实验室里做这项工作的。根据这三个目标区域的结果，我们将提供可用于开发抗真菌植物病害新方法的信息。因此，这项研究将为学生提供很好的培训，并为可持续粮食生产提供重要进展。

Fungal diseases of plants are a major contributor to the world food crisis. In Canada the loss to the wheat crop alone because of the leaf rust fungus can be $100 million annually. The rust fungi can only be grown in the plant and are very difficult to work with. In contrast, the related corn smut fungus, Ustilago maydis, can be easily grown and there are protocols for detailed investigation with this fungus. So, while this fungus causes serious damage to corn crops and therefore must be understood, it also acts as a model to understand all rust and smut diseases. In my last NSERC grant we further developed the model aspect of the smut fungus through genomic analysis. This provided better tools for investigation and the ability to transfer the knowledge we gain to other fungi. We are now in an excellent position to use these tools to investigate three areas 1) gene expression control through antisense RNA expression, 2) control of sexual reproduction and 3) plant hormone production by the fungus. Fire and Mellow received a Nobel prize in 2006 for their discovery of antisense control of gene expression. While the system they described is at work in most organisms, the corn smut fungus has a different way to control gene expression by antisense. We will be figuring out what that is with the funds applied for. Sexual reproduction by fungal pathogens shuffles virulence genes and can lead to more deadly diseases. Our goal in project 2 is to understand how sex is controlled and how interaction with the host plant leads to sexual reproduction by the smut fungus. In project 3, I am collaborating with another Professor at Trent to determine how the smut fungus modifies the corn plant during infection. We have evidence that the fungus does this using plant hormones, and we require the funds to figure out how. We have the money for equipment from other funding sources, so the funds applied for here, are to support the students doing this work in the laboratory. With the results from these three targeted areas we will provide information that can be used to develop new ways to fight fungal plant diseases. Therefore, this research will provide great training for students and important advances for sustainable food production.