UKRI/BBSRC-NSF/BIO Determining the Roles of Fusarium Effector Proteases in Plant Pathogenesis

植物感染病原体分泌的一种被称为效应物的小蛋白质是美国、英国和其他地方许多实验室研究的重点，因为它们的研究揭示了病原微生物是如何引起植物疾病的。通常，这些效应研究还揭示了受攻击植物中调节免疫的关键宿主蛋白的身份。然而，尽管真菌病原体对全球粮食安全，在某些情况下对人类和动物健康构成非常严重的风险，但我们对引起不同植物疾病的微观丝状真菌产生的效应物的了解仍然非常有限。其中一种病原体是镰刀菌（Fusarium graminearum, Fg），它在小麦和大麦上引起镰刀菌头疫病（Fusarium Head Blight， FHB），但它也感染数十种其他植物物种，包括进口的全球作物物种玉米、水稻、大豆和模式实验物种拟南芥。粮食作物的FHB病害发生在作物开花（花期）后，并继续降低粮食产量和粮食品质。特别令人担忧的是，这种疾病用一种称为真菌毒素的有毒化合物污染谷物，最常见的是脱氧雪腐镰刀菌醇（DON）。目前的食品毒素控制措施复杂但不充分，包括部署部分抗性的品种，使用部分有效的杀菌剂和改变农业做法。因此，需要严格立法并在收获后和加工链中清除/减少霉菌毒素污染的谷物，以确保食品和饲料对谷物消费者（即人类、养殖动物和鸟类）是安全的。到2050年，世界人口预计将增加20亿，为满足预期的粮食需求，我们必须减少粮食计划署的作物损失。该项目的目标是开发小麦和大麦对引起FHB疾病的镰刀菌的遗传抗性。植物具有检测致病病原体的能力，然后激活强大的防御反应，最终导致局部细胞死亡以阻止入侵者。为了检测病原体，植物使用被病原体在感染过程中分泌的酶修饰的传感蛋白。本项目的重点是鉴定真菌Fg分泌的酶，这些酶是小麦和大麦花组织感染所必需的。一旦这些酶被识别出来，传感器蛋白将被设计出来，在这些Fg酶的修饰下，可以激活小麦和大麦的防御反应。因此，这样的系统可以在不使用昂贵且对环境有害的杀虫剂的情况下，赋予对引起FHB疾病的镰刀菌感染的抵抗力。这种控制镰刀菌的方法应该可以广泛应用于被其他镰刀菌损害的重要作物。这项美英合作项目将涉及英国洛桑研究所、美国印第安纳大学和美国普渡大学USDA-ARS实验室的多学科团队。

Small proteins called effectors secreted by plant infecting pathogens are a focus of research in numerous laboratories in the USA, UK and elsewhere, because their study sheds light on how pathogenic microbes cause plant disease. Often these effector studies also reveal the identity of key host proteins in the attacked plants that regulate immunity. However, our knowledge of effectors produced by microscopic filamentous fungi that cause different plant diseases is still quite limited, even though fungal pathogens represent very serious risks to global food security and in some cases human and animal health. One such pathogen is Fusarium graminearum (Fg), which causes Fusarium Head Blight (FHB) on wheat and barley, but which also infects dozens of other plant species, including the import global crop species maize, rice, soybean and the model experimental species Arabidopsis. FHB disease in cereal crops occurs just after crop flowering (anthesis) and goes on to reduce grain yield and grain quality. Particularly concerning is that this disease contaminates grain with toxic compounds called mycotoxins, with the most common being deoxynivalenol (DON). Current FHB control measures are complex but inadequate, involving deploying partially resistant cultivars, using partially effective fungicides and altering agricultural practices. As a consequence, strict legislation and the removal/reduction of mycotoxin contaminated grains post-harvest and in processor chains is needed to ensure food and feed are safe for grain consumers (i.e., humans, farmed animals and birds). To meet expected food demand in 2050, when the world is projected to have an additional 2 billion people, it is imperative that we reduce crop losses to FHB. The goal of this project is to develop genetic-based resistance in wheat and barley to Fusarium species that cause FHB disease. Plants have the ability to detect disease-causing pathogens and then activate a robust defence response that ultimately leads to localised cell death to stop the invader. To detect pathogens, plants use sensor proteins that are modified by enzymes that pathogens secrete during the infection process. This project focuses on identifying enzymes secreted by the fungus Fg that are required for infection of wheat and barley floral tissues. Once such enzymes are identified, sensor proteins will be designed that can activate defence responses in wheat and barley upon modification by these Fg enzymes. Such a system would thus confer resistance to infection by Fusarium species that cause FHB disease without the use of costly and environmentally damaging pesticides. This approach to Fusarium control should be transferrable to a wide array of important crop plants that are damaged by other Fusarium species. This collaborative US-UK project will involve multidisciplinary teams at Rothamsted Research, UK, Indiana University, Indiana, USA and the USDA-ARS laboratory at Purdue University, Indiana, USA.