Molecular genetics of smut fungi

我们的长期目标是了解真菌病原体如何导致对加拿大具有经济重要性的作物和树木的疾病。 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。 我们研究的病原体攻击谷物作物的相关加拿大，包括玉米病原体玉米黑粉菌。 这种真菌会引起一种引人注目的疾病，玉米穗会转化为巨大的肿瘤，最终充满黑色的真菌孢子（称为黑穗病，因为它们的黑色，不规则的外观）。 这些孢子传播疾病并污染未受感染植物的谷物。联合玉米是对玉米生产的威胁，也是一种有价值的实验生物，有助于了解其他相关真菌病原体如何导致小麦、大麦和燕麦的作物产量和质量的重大损失。 在我们的项目中，我们专门研究了U.玉米是入侵植物所必需的。 我们还想了解病原体如何感知植物宿主的环境，以及入侵后如何获得营养。 我们的工作导致发现了内源性真菌因子（交配信号），脂质和磷酸盐作为信号和营养物质，影响感染期间的丝状生长。 最近，我们采用了最先进的分子技术来鉴定所有约6,500个U.玉米和所有大约32,000个玉米基因。 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导致代谢（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哪些预测的病原体蛋白质（6,500个）实际上进入叶绿体造成损害并阻止植物防御。我们进行了初步的实验，以确认我们可以识别这些蛋白质，我们现在有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。 总之，这些实验将提供一个详细的图片，如何美国。玉米会侵害玉米植株。 随后，我们将利用遗传技术来阻断特定U.我们将利用生物化学技术来确定关键蛋白的作用机制。 鉴定这些蛋白质是重要的，因为它们的特性可能揭示新的策略，以控制真菌病害和保护作物。

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.