Host defense peptides and mechanisms of broad-spectrum disease resistance in plants.

致病真菌、卵菌和细菌是植物病害的主要原因，占全世界作物损失总额的三分之一以上。开发具有持久、广谱抗病性的植物是继续满足当前和未来世界粮食需求的最大挑战之一。本研究计划的目标是对马铃薯中天然宿主防御肽（HDPs）的特性及其在保护植物免受病原微生物侵害中的主要作用进行基础研究。这些肽，也被称为阳离子抗菌肽，代表了一个不同的小的膜活性分子家族，在许多进化上遥远的生物中发现，从原始无脊椎动物到植物和人类，被认为是抵抗病原体入侵的先天防御系统的一部分。HDPs最重要和独特的特点是，它们针对微生物膜和动植物膜之间的基本设计差异，这使它们比其他防御分子具有明确的优势。因此，与其他化合物相比，病原体出现耐药菌株的可能性较小。本研究的新颖之处包括利用天然植物防御肽（HDPs）开发马铃薯的广谱抗病性，验证HDPs在植物先天免疫反应中作为免疫调节剂的假设，在一株植物中同时表达不同的HDPs编码基因（基因金字塔），诱导和器官特异性表达HDPs，以及探索马铃薯块茎作为低成本、安全、有效的治疗性HDPs生产平台的适用性。该研究将阐明hdp介导的植物抗病的分子机制，包括hdp的作用模式及其抗菌活性所必需的结构基序，它们在寄主植物中的细胞内定位和运输，并将阐明hdp在植物功能中其他未知的作用，这些作用导致植物生产力的提高和产量的提高。这项研究计划对加拿大的直接影响是，由此产生的马铃薯基因型可以作为传统马铃薯育种计划中有价值的防御基因（种质）的来源。其他好处包括更高的产量，减少收获后损失，以及由于真菌毒素污染物水平降低而改善的食品安全。此外，这种方法也可用于提高其他作物的抗病性。最后，HQP参与这个独特的研究项目将接触到各种各样的实验学习机会，这对他们未来在学术界、政府和工业界的职业生涯至关重要。

Pathogenic fungi, oomycetes, and bacteria are the leading cause of plant diseases, contributing to more than one-third of total crop losses throughout the world. Development of plants with durable, broad-spectrum disease resistance is one of the greatest challenges in continuing to meet current and future world food needs. The goal of this research program is to conduct fundamental studies of the properties of natural host defense peptides (HDPs) in potatoes, and their primary roles in the protection of plants against pathogenic microorganisms. These peptides, also called cationic antimicrobial peptides, represent a diverse family of small, membrane-active molecules that are found in many evolutionarily distant organisms, ranging from primitive invertebrates to plants and humans, and are thought to be part of the innate defense system against pathogen invasion. The most important and unique feature of HDPs, which gives them a well-defined advantage over other defensive molecules, is that they target the fundamental design differences between microbial membranes and the membranes of plants and animals. Therefore, the emergence of resistant strains of the pathogens is less probable compared to that of other compounds. The novelty of this research includes the development of broad-spectrum disease resistance in potato using natural plant defense peptides (HDPs), testing hypothesis of HDPs as immunomodulators in plant innate immune response, simultaneous expression of different HDP-coding genes in one plant (gene pyramiding), induced and organ-specific expression of HDPs, and exploring the suitability of potato tubers as low cost, safe, and effective platform for the production of therapeutic HDPs. The research will elucidate the molecular mechanism(s) of HDP-mediated disease resistance in plants, including the mode of action of HDPs and their structural motifs essential for antimicrobial activity, their intracellular localization and transport within the host plant, and will clarify other, unknown roles of HDPs in plant functions that result in improved plant productivity and higher yield. The immediate impact of this proposed research program to Canada is that the resulting potato genotypes can be used as a source of valuable defense genes (germplasm) in conventional potato breeding programs. Other benefits include higher yields, reduced post-harvest losses, and improved food safety due to lower level of fungal toxin contaminants. In addition, this approach may be useful to improve disease resistance in other crops. Finally, HQP involved in this unique research program will be exposed to a variety of experimental learning opportunities, essential for their future careers in academia, government, and industry.