Oxylipins:novel sources of soybean disease tolerance against Phytophthora sojae infection

项目背景：抗病性是宿主植物在受到病原体感染的情况下仍能生长并产生公平产量而不表现出严重症状的一种防御策略。氧脂素（氧化脂肪酸）是在许多宿主病原体关系中响应于感染而产生（诱导）的第一防御化合物之一。存在超过200种氧化脂质，它们形成植物防御策略的一部分，作为诱导防御反应的信号分子，或直接作为抗微生物化合物发挥作用。这些作用模式表明，氧化脂质可能是在特定的宿主病原体关系，如大豆疫霉（P.sojae）的病理系统的新的疾病耐受性的有效的生化来源。 问题陈述：由大豆疫霉引起的根和茎腐烂在全世界造成了超过10亿美元的大豆作物损失。疾病管理战略目前正在寻求新的持久抗性来源，以防止作物损失。 我们之前的研究（Ranatunge et al 2008）表明，耐受大豆品种快速诱导蜡质和木栓质合成，作为控制大豆疫霉感染的成功策略的一部分。然而，它是未知的什么样的作用，氧脂在这个或其他成功的主机防御反应在这个病理系统。 假设：氧脂蛋白在大豆-大豆疫霉致病系统中脂肪酸介导的防御反应和抗病性中起重要作用，并且在该致病系统中具有作为抗病性的新生化来源的潜在用途。 长期目标：了解大豆-大豆疫霉病理系统中成功的抗病/耐病机制。 短期目标：具体而言，我将研究以下内容在大豆-大豆疫霉致病系统中：1）植物氧化脂素诱导响应宿主定殖和感染2）氧化脂素在致病过程中的植物保护、抗菌或毒力作用3）植物和病原体来源的氧化脂素与抗病性或致病性的空间相关性。 方法学：试验杯接种方法将与色谱、脂质成像、振动光谱和质谱技术一起沿着使用，以确定敏感和耐受大豆栽培品种中大豆疫霉感染后的氧脂素反应。 重要性：该研究将为大豆疫霉致病系统中氧化脂素诱导/代谢在抗病性或致病机制中的作用提供新的发现和认识。这些发现的结果可用于开发新的耐受性生物化学来源，以提高大豆对大豆疫霉引起的根腐病和茎腐病的先天抗性。在大豆中开发提高的大豆疫霉耐受性将是一种有效的长期作物保护策略，其有益于减少全球因大豆疫霉感染而造成的数十亿美元的大豆产量损失。

Project Context: Disease tolerance is a defense strategy used by host plants to grow and produce equitable yield without displaying severe symptoms despite being infected by a pathogen. Oxylipins (oxygenated fatty acids) are among the first defense compounds produced (induced) in response to infection in a number of host pathogen relationships. There are over 200 oxylipins in existence that form part of the plant defense strategy, serving as signal molecules to induce defense responses, or function directly as antimicrobial compounds. These mode of actions indicate oxylipins could be potent biochemical sources of novel disease tolerance in specific host pathogen relationships such as the soybean Phytophthora sojae (P.sojae) pathosystem. Problem statement: Root and stem rot caused by P.sojae account for over a billion dollars in soybean crop loss worldwide. Disease management strategy currently seeks new sources of durable resistance to protect against crop losses. Previous research by us (Ranatunge et al 2008), demonstrated that tolerant soybean cultivars rapidly induced wax and suberin synthesis as part of a successful strategy to control P.sojae infection. However, it is unknown what role oxylipins play in this or other successful host defense response in this pathosystem. Hypothesis: Oxylipins play a significant role in fatty acid mediated defense response and disease tolerance in the soybean- P. sojae pathosystem, and have potential uses as novel biochemical sources of disease tolerance in this pathosystem. Long term objectives: To understand the mechanisms underlying successful disease tolerance/resistance in the soybean- P. sojae pathosystem. Short term objectives: Specifically, I will study the following in the soybean- P. sojae pathosystem:1) plant oxylipin induction in response to host colonization and infection 2) the phytoprotective, antimicrobial or virulence effects of oxylipins during pathogenesis, 3) spatial relevance of plant and pathogen derived oxylipins to disease tolerance or pathogenicity. Methodology: Test cup inoculation methods will be used along with chromatographic, lipid imaging, vibrational spectroscopic and mass spectrometric techniques to determine oxylipin response following P.sojae infection in susceptible and tolerant soybean cultivars. Significance: The proposed research will provide novel discoveries and improve our understanding concerning oxylipin induction/metabolism in disease tolerance or pathogenesis in the soybean- P. sojae pathosystem. The outcome of these findings could be used to develop novel biochemical sources of tolerance to improve the innate resistance of soybeans to root and stem rot caused by P. sojae. Development of increased P. sojae tolerance in soybeans will be an effective long term crop protection strategy beneficial in reducing billions of dollars in soybean yield losses globally to P. sojae infection.