Molecular genetics of smut fungi

黑穗病真菌的分子遗传学

• 批准号: RGPIN-2017-03928
• 负责人: Kronstad, James
• 金额: $ 6.56万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708949
• 关键词: Molecular; genetics; smut; fungi

Our long-term goal is to understand how fungal pathogens cause diseases on crops and trees of economic importance to Canada. Ultimately, we want to contribute to new strategies for plant protection and sustainable agriculture. We study pathogens that attack cereal crops of relevance to Canada including the corn pathogen Ustilago maydis. This fungus causes a dramatic disease in which ears of corn are converted to large tumors that eventually fill with black masses of fungal spores (called smuts because their black, sooty appearance). These spores spread the disease and contaminate grain from uninfected plants. U. maydis is a threat to corn production and it is also a valuable experimental organism for understanding other how related fungal pathogens cause substantial losses in crop yield and quality for wheat, barley and oats. In our program, we specifically investigate the formation and proliferation of specialized cells (filaments) of U. maydis that are required to invade plants. We also want to understand how the pathogen senses the environment of the plant host and how it obtains nutrients after invasion. Our work led to the discovery of endogenous fungal factors (mating signals), lipids and phosphate as signals and nutrients that influence filamentous growth during infection. Recently, we employed state of the art molecular technology to identify changes in expression during disease for all of the approximately 6,500 genes of U. maydis and all of the approximately 32,000 corn genes. This work revealed key features of nutrient acquisition by the fungus and important defense changes in the plant. Importantly, we discovered that infection by the pathogen results in destruction of the key plant structures (chloroplasts) required for metabolism (photosynthesis for example) and defense. To take advantage of our discoveries, we plan to use the latest technologies for measuring proteins to determine which of the predicted pathogen proteins (out of 6,500) actually enter chloroplasts to cause damage and block plant defense. We performed a preliminary experiment to confirm that we can identify these proteins and we now have a preliminary list of candidates. In parallel, we plan to measure changes in chemicals associated with chloroplast function and defense using analytical methods. Together, these experiments will provide a detailed picture of how U. maydis attacks corn plants. Subsequently, we will use genetic techniques to block the ability of specific U. maydis proteins to damage chloroplasts, and we will use biochemical techniques to determine the mechanism(s) of action of key proteins. It is important to identify these proteins because their characterization may reveal new strategies to control fungal diseases and protect crops.

我们的长期目标是了解真菌病原体如何在对加拿大具有重要经济意义的农作物和树木上引起疾病。最终，我们希望为植物保护和可持续农业的新战略做出贡献。我们研究攻击与加拿大相关的谷类作物的病原体，包括玉米病原菌Ustilago maydis。这种真菌引起一种戏剧性的疾病，玉米的耳朵会转化为大肿瘤，最终充满黑色的真菌孢子块(称为黑粉病，因为它们看起来黑色，煤烟味)。这些孢子传播疾病，污染未受感染植物的谷物。玉米单胞菌对玉米生产构成威胁，也是了解相关真菌病原菌如何对小麦、大麦和燕麦的产量和品质造成重大损失的有价值的实验生物。 在我们的计划中，我们专门研究入侵植物所需的玉米单胞菌的特化细胞(细丝)的形成和增殖。我们还想了解病原体如何感知植物寄主的环境，以及它在入侵后如何获得营养。我们的工作导致了内源真菌因子(交配信号)的发现，脂质和磷酸盐作为信号和营养在感染过程中影响丝状菌的生长。最近，我们使用最先进的分子技术来鉴定所有大约6,500个玉米单胞菌基因和所有大约32,000个玉米基因在疾病期间的表达变化。这项工作揭示了真菌获取营养的关键特征和植物中重要的防御变化。重要的是，我们发现病原体的感染会导致新陈代谢(例如光合作用)和防御所需的关键植物结构(叶绿体)的破坏。 为了利用我们的发现，我们计划使用最新的蛋白质测量技术来确定预测的病原体蛋白质中的哪些实际上进入叶绿体造成损害并阻止植物防御。我们进行了初步实验，以确认我们可以识别这些蛋白质，现在我们有了一个初步的候选名单。同时，我们计划使用分析方法测量与叶绿体功能和防御相关的化学物质的变化。总而言之，这些实验将提供一幅美国梅迪斯是如何攻击玉米植株的详细图景。随后，我们将使用基因技术来阻断特定的玉米黑粉菌蛋白对叶绿体的损伤能力，并将使用生化技术来确定关键蛋白的作用机制(S)。鉴定这些蛋白质很重要，因为它们的特性可能揭示控制真菌疾病和保护作物的新策略。