Investigating control of Ustilago maydis teliospore formation, dormancy and germination

研究玉米黑粉菌冬孢子形成、休眠和萌发的控制

• 批准号: RGPIN-2019-06029
• 负责人: Saville, Barry
• 金额: $ 3.42万
• 依托单位: Trent University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738666
• 关键词: Investigating; control; Ustilago; maydis; teliospore

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

农作物生产是价值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，真菌疾病通过大量具有抗性的孢子传播。目前对疾病形成的研究尚未产生抗击真菌疾病的新方法。在这里，我提出了另一个重点，阻止孢子产生和疾病传播，作为一个可以开发抗击真菌的新方法的领域。自从发现微生物致病以来，我们就知道了孢子的作用。作物中真菌病的明显迹象往往与孢子的产生有关。然而，我们对真菌如何影响植物以帮助它们发育和散布孢子的了解有限。我的实验室已经开发出利用常见的玉米黑粉菌--玉米黑粉菌研究真菌病害的技术。我们正在确定：1.真菌如何利用激素来计时孢子的形成；2.不同的真菌如何操纵寄主产生孢子；3.休眠的孢子如何变得活跃我们发现玉米根霉产生细胞分裂素(CKS)，这是一种随着疾病的发展而改变植物的植物激素。梅迪氏杆菌在感染期间也可以检测到Cks，这表明它可能会监测Cks的水平，以便对其孢子的产生进行计时。我们将研究当Cks存在时真菌和植物开启和关闭哪些基因。然后我们将确定改变这些基因的表达如何影响孢子发育。我们发现，玉米黑粉菌可以与一种亲缘关系密切的真菌雷氏孢子菌杂交产生杂交后代。双亲都侵染玉米，但玉米单胞菌在侵染部位周围产生病害症状和孢子，而雷氏链霉菌进入玉米并系统生长，只在雄穗和玉米棒中产生病害症状和孢子。这些杂交种在培养上与玉米大麦相似，但在植物中不会产生孢子。我们将确定在感染期间，哪些梅氏杆菌致病基因在杂交种中处于打开或关闭状态，以及改变某些基因的表达是否有助于杂交种形成孢子。这将识别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，即孢子的萌发。一旦形成，这些抗性结构就会进入休眠状态。我们已经开发了工具来帮助我们研究当孢子萌发时，梅迪斯是如何控制新陈代谢活动的恢复的。了解这种回到疾病产生状态的受控状态，可能会让我们发现阻止它和防止疾病传播的新方法。通过这项研究获得的知识将有助于开发防止真菌病传播的新方法，以提高作物生产的可持续性。