Metabolomic analysis of the plant pathogenic microbes Fusarium graminearum and F. culmorum

许多微生物专门攻击植物和农作物，以完成它们的生命周期。一些微生物感染会降低作物产量，而另一些则会降低收获产品的质量，例如在苹果上引起斑点。这两种情况都可能严重影响农场的利润率，并可能在某些国家导致粮食短缺。另一组攻击植物的微生物更令人担忧。这是因为在感染植物组织的过程中，它们会产生特定的毒素，称为霉菌毒素，即使食用少量也会对人类和动物的健康有害。准确检测散装谷物以及生水果和蔬菜产品中这些霉菌毒素的存在非常困难，而且价格昂贵。一种被称为镰刀菌疮痂病真菌的微生物引起了越来越多的国际关注（http：www.scabusa.org），因为它感染所有谷类植物物种（小麦、大麦、玉米和水稻）的花，并且在这些感染期间，谷物被称为DON的高毒性、水溶性真菌毒素污染，通常被称为呕吐毒素，因为它在摄入时对人类产生影响。有趣的是，镰刀菌真菌只在植物组织内生长或在模拟植物内部富含碳和氮的实验室条件下生长时才会产生真菌毒素。在这个项目中，我们希望了解镰刀菌是如何转换真菌毒素的生产的。这已经通过确定11，640个镰刀菌属基因中的每一个的表达是否在真菌毒素诱导条件下特异性地打开、关闭或不改变而进行了探索。为了补充这项研究，我们计划在精确的实验室条件下研究当DON产生时镰刀菌真菌内部的生物化学发生了什么变化。我们计划详细探索镰刀菌真菌内部产生的水溶性小化学分子的全球变化。为了增加我们对这一过程的理解，我们还计划在相同的条件下测试多达100种不同的镰刀菌突变株，每种突变株都有一个基因被删除。据预测，镰刀菌共有11,640个基因。因此，我们打算仅关注去除不同关键内部调节因子的基因缺失菌株，以及已知损害DON产生或植物感染过程的其他基因缺失菌株。为了帮助解释复杂的镰刀菌结果，我们将模拟观察到的小分子变化，从而产生工作假设，通过后续实验进行测试。除了帮助我们解释镰刀菌的结果，我们将包括一些比较实验与两个良好的/研究的真菌物种，即面包酵母，通过出芽生长和一个自由生活的丝状真菌称为脉孢菌。这项研究应该帮助我们设计出各种方法来阻止镰刀菌感染谷类作物或在发育中的谷物中产生真菌毒素。

Many micro-organisms specialise in attacking plants and agricultural crops to complete their lifecycle. Some microbial infections lower crop yields, whilst others lower the quality of the harvested product, for example, causing spots on apples. Both these situations can seriously affect farm profit margins and may in certain countries lead to food shortages. Another group of micro-organisms which attack plants are of even greater concern. This is because during the infection of plant tissue they produce specific toxins, called mycotoxins, which are harmful to human and animal health even when eaten in only modest quantities. The accurate testing for the presence of these mycotoxins in bulk grain as well as raw fruit and vegetable products is very difficult and is also expensive. A micro-organism called the Fusarium scab fungus is of growing international concern (http://www.scabusa.org) because it infects the flowers of all cereal plant species (wheat, barley, maize and rice) and during these infections the cereal grain becomes contaminated with a highly toxic, water soluble, mycotoxin called DON, commonly known as vomitoxin because of the effects it causes on humans when ingested. Interestingly the Fusarium fungus only produces mycotoxins when it grows inside plant tissue or under conditions in the laboratory which mimic the carbon and nitrogen rich interior of the plant. In this project we wish to understand how the Fusarium fungus switches on mycotoxin production. This has already been explored, by determining whether the expression of each of the 11,640 Fusarium genes is specifically switched on, off or do not alter under mycotoxin inducing conditions. To complement this study, we plan to investigate under precise laboratory conditions what happens to the biochemistry inside the Fusarium fungus as DON production is switched on. We plan to explore in detail the global changes in the small water soluble chemical molecules made inside the Fusarium fungus. To increase our understanding of this process, we also plan to test under the identical conditions up to 100 different mutant strains of the Fusarium fungus which each have a single gene removed. The Fusarium fungus is predicted to have in total 11,640 genes. Therefore we intend only to focus on gene deletion strains which remove different key internal regulators, and other which are known to compromise DON production or plant infection processes. To help interpretation the complex Fusarium results we will modelling the changes in small molecules observed and thereby generate working hypotheses to test by subsequent experimentation. In addition to assist us in interpreting the Fusarium results we will include some comparable experiments with two well/studied species of fungi, namely baker's yeast which grows by budding and a free living filamentous fungus called Neurospora. The research should help us to devise various ways either to stop the Fusarium fungus from infecting cereal crops or from producing mycotoxins in the developing grain.