Investigation of host resistance to Fusarium graminearum in common wheat (Triticum aestivum L.)

镰刀菌头枯病（FHB）是一种毁灭性的小麦病害，自20世纪80年代初以来，加拿大生产商已损失超过10亿美元。在加拿大，这种疾病的主要致病因子是真菌病原体禾谷镰刀菌。感染F.禾谷早熟禾导致产生皱缩或皱缩的籽粒，这降低了作物产量并损害了最终使用质量。真菌毒素如脱氧雪腐镰刀菌烯醇（DON）在受感染的谷物中积累。霉菌毒素对人类和一些动物有毒，并限制了谷物的销售和价值。食品和饲料中霉菌毒素的国际低限对加拿大谷物的市场销售构成威胁。在小麦品种中引入遗传抗性是控制赤霉病多管齐下策略的重要组成部分。小麦赤霉病抗性有五种类型。对初始感染的抗性（I型）和对感染传播的抗性（II型）已经被科学家很好地表征，并且已经确定了许多抗性来源。然而，即使具有I型和II型抗性，一些小麦基因型积累的霉菌毒素水平也显著高于其他基因型。DON含量对食品和饲料安全构成最大威胁，并且被认为是镰刀菌感染小麦中疾病进展的主要贡献者。本研究的长期目标是了解小麦抗性和管理措施在小麦DON积累中的作用。这将通过以下方式实现：1）定位冬小麦群体中控制DON积累以及病害发生率、严重度、指数和镰刀菌损害籽粒的基因，并检查不同FHB反应测量值之间的关系; 2）调查候选抗性基因与DON积累之间的关系; 3）确定管理、感染时间、收获前和收获条件在籽粒中DON积累中的作用。这项研究将大大减少FHB的损失，提高世界各地生产的小麦的食品和饲料安全性。

Fusarium head blight (FHB) is a devastating disease of wheat that has cost Canadian producers in excess of one billion dollars since the early 1980s. The primary causal agent of this disease in Canada is the fungal pathogen Fusarium graminearum. Infection with F. graminearum leads to development of shrunken or shrivelled kernels which reduce crop yield and compromise end-use quality. Mycotoxins such as deoxynivalenol (DON) accumulate in the infected grain. Mycotoxins are toxic to humans and some animals, and limit the marketability and value of the grain. Low international limits for mycotoxins in food and feed pose a threat to marketability of Canadian grain. Incorporation of genetic resistance in wheat cultivars is an essential component of the multi-pronged strategy for FHB control. Five types of FHB resistance have been described in wheat. Resistance to initial infection (Type I) and resistance to spread of infection (Type II) have been well characterized by scientists and numerous sources of resistance have been identified. However, even with Type I and II resistance, some wheat genotypes accumulate significantly higher levels of mycotoxin than others. DON content poses the biggest threat to food and feed safety and is considered to be a major contributor to disease progression in Fusarium infected wheat. The long term objectives of this research are to understand the role of wheat resistance and management practices in DON accumulation in wheat. This will be achieved by: 1) Mapping genes controlling DON accumulation as well as disease incidence, severity, index and Fusarium damaged kernels in winter wheat populations and examining the relationship between the different measurements of FHB reaction, 2) Investigating the relationship between candidate resistance genes and DON accumulation, and 3) Determining the role of management, timing of infection, pre-harvest and harvest conditions in DON accumulation in grain. This research will significantly reduce losses to FHB, improve food and feed safety of wheat produced around the world.