Investigating control of Ustilago maydis teliospore formation, dormancy and germination

农作物生产是数十亿美元的农业和农业食品部门的主要组成部分，该部门雇用了200多万加拿大人。这种生产受到真菌疾病增加的威胁，真菌疾病是由大量的抗性孢子传播的。目前对疾病形成的研究重点还没有产生对抗真菌疾病的新方法。在这里，我提出了一个替代的重点，阻止孢子的生产和疾病的传播，作为一个领域，可以开发新的方法来对抗真菌。 自从发现微生物引起疾病以来，我们已经知道了孢子的作用。农作物真菌病害的明显症状通常与孢子产生有关。然而，我们对真菌如何影响植物以帮助它们发育和传播孢子的知识是有限的。我的实验室已经开发出利用普通玉米黑穗病菌（Ustilago maydis）调查真菌植物病害的技术。我们决定：1。真菌如何使用激素来确定孢子形成的时间; 2.不同的真菌如何操纵宿主产生孢子，以及3。休眠的孢子如何变得活跃我们发现，U。玉米产生细胞分裂素（CKs），这是随着疾病发展而改变植物的植物激素。联合玉米还可以在感染过程中检测到CK，这表明它可能会监测CK的水平，以确定其孢子产生的时间。我们将研究当CK存在时真菌和植物打开和关闭哪些基因。然后，我们将确定如何改变这些基因的表达影响孢子发育。 我们发现，U。玉米可以与一种密切相关的真菌丝孢霉（Sporisorium reilianum）杂交产生杂种。双亲都感染玉米，但U。maydis在感染部位周围产生病害症状和孢子，而S. reilianum进入玉米并全身生长，仅在雄穗和穗轴中产生病害症状和孢子。杂交种的生长情况与美国的相似。在培养物中，它们可以产生玉米，但在植物中，它们不产生孢子。我们将决定哪一个美国。在感染过程中，玉米致病基因在杂交种中被打开或关闭，以及改变某些基因的表达是否有助于杂交种形成孢子。这将确定在孢子产生中起作用的基因，并揭示杂交如何导致新型病原体。 在第三个项目中，我们将研究疾病传播的另一个方面，孢子的萌发。一旦形成，这些抵抗结构就会休眠。我们已经开发了一些工具来帮助我们研究美国是如何做到的。玉米淀粉控制孢子萌发时代谢活动的恢复。了解这种回到疾病产生状态的过程是受控的，可能会让我们发现阻止它和预防疾病传播的新方法。 通过这项研究获得的知识将有助于开发新的方法来防止真菌疾病的传播，以提高作物生产的可持续性

Crop production is a major component of the multi-billion dollar agricultural and agrifood sector that employs over two million Canadians. This production is threatened by an increase in fungal diseases that are spread by massive numbers of resistant spores. The current research focus on disease formation has not produced new ways to fight fungal diseases. Here I present an alternative focus, blocking spore production and disease spread, as an area where novel approaches for battling fungi could be developed. We have known about the role of spores since the discovery that microbes cause disease. Obvious signs of fungal disease in crops are often associated with spore production. However our knowledge of how fungi influence plants to help them develop and disperse spores is limited. My laboratory has developed techniques for investigating fungal plant disease using the common corn smut fungus, Ustilago maydis. We are determining: 1. How the fungus uses hormones to time spore formation; 2. How different fungi manipulate the host to produce spores, and 3. How dormant spores become active We discovered that U. maydis produces cytokinins (CKs), plant hormones that alter the plant as disease develops. U. maydis can also detect CKs during infection suggesting that it might monitor levels of CKs in order to time the production of its spores. We will investigate which genes the fungus and the plant turn on and off when CKs are present. Then we will determine how altering the expression of these genes influences spore development. We found that U. maydis can cross with a closely related fungus Sporisorium reilianum to produce hybrids. Both parents infect maize but U. maydis produces disease symptoms and spores around the site of infection, whereas, S. reilianum enters maize and grows systemically producing disease symptoms and spores only in the tassels and cobs. The hybrids grow similar to U. maydis in culture but in the plant they do not produce spores. We will determine which of the U. maydis pathogenesis genes are turned on or off in the hybrid during infection and whether changing the expression of certain genes can help the hybrid form spores. This will identify genes with roles in spore production and uncover how hybridization could lead to new types of pathogens. In the third project we will investigate another aspect of disease spread, the germination of spores. When formed, these resistant structures become dormant. We have developed tools to help us study how U. maydis controls the return to metabolic activity as spores germinate. Understanding this return to a disease producing state is controlled may allow us to uncover novel ways of stopping it and of preventing disease spread. The knowledge gained through this research will contribute to the development of novel approaches for preventing fungal disease spread to improve the sustainability of crop production