Deconstructing the polysaccharide matrix of the Magnaporthe oryzae wall: Deciphering the role of Gel remodelling enzymes

下个世纪的两大全球挑战将是如何确保全球粮食安全和如何应对新出现的疾病。对植物来说，没有比真菌更致命的病原体了-真菌疾病摧毁了我们的收成，并导致广泛的营养不良和饥饿。但随着全球气候变化加速地理传播和感染植物的种类，疾病的负担正在增加。因此，出于社会和经济原因，迫切需要解决这一问题。三种作物，即小麦、水稻和玉米，占据了我们全球约40%的耕地。其中，大米养活了世界上一半的人，随着未来40年人口增加30亿，大米将变得更加重要。稻瘟菌对水稻和全球粮食安全构成了非常严重的威胁，因为它有能力寄生“啤酒花”，即传播到新的草种。疾病会使大米收成减少近三分之一，在大米是主要营养来源的国家造成灾难性后果。它也是一个了解英国主要谷物疾病的模型系统。我们需要新的抗真菌化学药物来摧毁真菌孢子，从而防止疾病的传播。这种化学方法必须对环境友好，活性低，而且廉价易得。我们将研究将多糖构建块排列并粘合到真菌壁框架中的过程，并试图干扰这种活动。除了我们最近在牛津大学的工作外，人们对稻瘟病真菌墙中的这些过程一无所知。我们已经证明，壁架的一个关键成分在萌发过程中大量表达，它向壁上和内壁添加短糖。当我们从真菌中移除有助于这种活动的基因时，它仍然会生长，尽管很虚弱，但引起的疾病要少得多，并在这样做的过程中脱落一些墙壁。这种棚壁碎片似乎在植物中触发了一种早期的疾病保护机制。我们想更多地了解这一点，并最终了解将其他糖粘合到壁上和壁内并改变其硬度的其他成分，以及它们是否也提高了植物的疾病免疫力。此外，我们已经证明了一种环境友好的PuriCore化学物质，在美国用于保存超市沙拉，是抗真菌的，它会影响墙壁的完整性。我们已经证明，低剂量的这种化学物质可以防止萌发，导致孢子崩溃和壁部分脱落。我们希望更好地了解这种细胞壁扰动，它对细胞壁周转的影响，以及它是否导致细胞壁糖网的变化。我们处于得天独厚的地位，可以利用我们现有的所有必要工具和技术开展这项工作。

Two of the major global challenges for the next century will be how to ensure global food security and how to contend with emerging diseases. No pathogens are more deadly to plants than fungi - fungal diseases decimate our harvests and cause widespread malnutrition and starvation. But the burden of disease is increasing as global climate change hastens the geographic spread and the variety of plants infected. Hence, there is an immediate need to address this problem for both social and economic reasons. Three crops, that is wheat, rice and maize, occupy some 40% of our global crop-land. Of these, rice feeds half the world's peoples, and will become yet more import as the population expands by 3 billion over the next 40 years. The rice blast fungus poses a very significant threat to rice and to global food security, given its ability to host "hop", that is, spread to new grass species. Disease can reduce the rice harvest by nearly a third, with catastrophic consequences in countries where rice is the main source of nutrition. It also acts as a model system for understanding the major cereal diseases of the UK. We need new antifungal chemistries which destroy fungal spores and so prevent spread of disease. Such chemistries must be environmentally-friendly, active at low doses and be cheap and accessible.We will look at the processes which align and cement the polysaccharide building blocks into the framework of the fungal wall and will attempt to interfere with such activities. Nothing is known of these processes in the rice blast fungal wall, save for our recent work at Oxford. We have shown that one pivotal component of the wall framework is abundantly expressed during germination and that it adds short sugars onto and into the wall. When we remove the gene that contributes to this activity from the fungus it still grows, albeit feebly, but causes considerably less disease, and sheds some of its wall as it does so. This shed wall debris appears to trigger an early disease protection mechanism in the plant. We want to know more about this and, eventually, other components that cement other sugars onto and into the wall and alter its stiffness and whether they too boost disease immunity in the plant. Moreover, we have demonstrated that an environmentally-benign PuriCore chemistry, used to preserve supermarket salads in USA, is antifungal and that it affects wall integrity. We have shown that low doses of this chemistry prevents germination, leads to spore collapse and the shedding of wall moieties. We wish to understand better this cell wall perturbant, its impact on wall turnover and whether it causes a change in the sugar meshwork of the wall. We are uniquely placed to undertake this work with all necessary tools and technologies available to us.