Secondary metabolism in plant pathogenic Streptomyces species

本实验室的研究重点是植物病原菌--链霉菌，它是引起世界范围内马铃薯赤霉病的病原。马铃薯纹枯病的特征是在马铃薯块茎表面形成浅部、凸起或凹陷的病斑，这些病斑降低了马铃薯作物的市场价值，给种植者造成了重大的经济损失。溃烂链霉菌之所以能够引起CS病，主要是由于产生了泰索托菌素A，这是一种植物毒素，在感染过程中可能会直接导致溃烂链霉菌对宿主组织的渗透。此外，溃烂链霉菌还产生一种植物毒素N-冠状因子-L-异亮氨酸(CFA-ILE)，其功能可能是作为一种植物激素类似物，以增强病原菌的定植和对植物寄主的侵染。尽管其中许多分子的身份和功能尚不清楚，但人们认为它们能够产生其他几个小分子，这些小分子可能有助于宿主与病原体的相互作用。这项研究将为CFA-Ile和紫杉素A植物毒素的生物合成和调控提供新的信息，并将揭示一个先前未被描述的小分子的性质和功能，该小分子被预测为由溃烂链霉菌产生。这样的信息将让我们更好地了解溃烂链霉菌是如何致病的，以及我们如何开发出更好的控制疾病的方法，这将对加拿大的马铃薯种植者有利。此外，拟议的研究将加深我们对小分子在调节微生物和植物之间的相互作用中的作用的理解。所描述的工作将导致在广泛的领域对本科生和研究生进行高质量的现代技术培训，包括微生物遗传学、蛋白质生物化学、小分子纯化和结构表征。此外，学员将有机会发展口头和书面沟通、项目管理和指导方面的技能。所接受的培训将为学生在学术界、工业或健康科学领域的各种职业道路做好准备，这将有利于加拿大社会。

Research in my lab focuses on the plant pathogenic bacterium Streptomyces scabies, which is a causative agent of potato common scab (CS) disease worldwide. CS is characterized by the formation of superficial, raised or pitted lesions on the surface of potato tubers, and these lesions reduce the market value of the potato crop and lead to significant economic losses for growers. The ability of S. scabies to cause CS disease is due primarily to the production of thaxtomin A, a plant toxin that may directly contribute to host tissue penetration by S. scabies during infection. In addition, S. scabies produces the plant toxin N-coronafacoyl-L-isoleucine (CFA-Ile), which may function as a plant hormone mimic in order to enhance pathogen colonization and infection of the plant host. S. scabies is thought to be able to produce several other small molecules that might contribute to host-pathogen interactions, though the identity and function of many of these molecules is unknown. This research will provide new information on the biosynthesis and regulation of the CFA-Ile and thaxtomin A plant toxins, and it will reveal new insights into the nature and function of a previously uncharacterized small molecule that is predicted to be made by S. scabies. Such information will allow us to better understand how S. scabies is able to cause disease and how we can develop better control methods for managing the disease, which will be beneficial to Canadian potato growers. In addition, the proposed research will enhance our understanding of the role of small molecules in mediating interactions between microorganisms and plants. The work described will lead to high quality training of undergraduate and graduate students in modern techniques in a broad range of areas, including microbial genetics, protein biochemistry, small molecule purification and structural characterization. In addition, trainees will have the opportunity to develop skills in oral and written communication, project management and mentorship. The training received will prepare students for a variety of career paths in academia, industry or the health sciences, which will be of benefit to Canadian society.