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Functional genomic characterization of germination and early infection of wheat by the fungus Zymoseptoria tritici.

小麦发酵菌对小麦发芽和早期感染的功能基因组特征。

基本信息

批准号：
BB/M022900/1
负责人：
Michael Deeks
金额：
$ 70.8万
依托单位：
UNIVERSITY OF EXETER
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FM022900%2F1
关键词：
Functional genomic characterization germination early

项目摘要

Providing enough food for all people on the planet is a major issue facing humanity in the 21st Century. As the Earth's population tops six billion the need to increase production of staple crops e.g. rice, wheat, banana is real. As the population grows to an anticipated nine billion by 2030 that demand will be even higher. In the UK wheat is a major crop, with 12.1 million tonnes, valued at more than £1.5 billion, produced in 2013. However, fungal disease, in particular septoria tritici blotch (STB), caused by Zymoseptoria tritici, is a major constraint on production. In untreated trials an average 20% of yield is lost, and in some cases field losses of 50% have been reported. Control of this disease could contribute an extra 2.4 - 6 million tonnes to the UK wheat harvest, and if applied to the global wheat harvest in 2013 would have delivered an extra 140 million tonnes into the food supply. There is no doubt that STB is a serious and immediate threat to global food security, and new control measures are urgently required. To initiate STB infection spores of Z. tritici alight on a leaf surface and germinate, beginning the disease process. This is followed by polarized growth development and passage into the interior of the leaf, usually within 12 hours. In susceptible wheat cultivars two days post-infection (dpi) the fungus has produced lateral branching and by 6-8 dpi this has developed to circumscribe a large area beneath the point of entry. At this stage the fungus has not yet invaded wheat cells and little evident symptomology is seen on the plant. However, 8-10 dpi symptoms begin to appear, concomitant with development of an incipient asexual reproductive structure, death of plant cells and a switch to parasitic growth. Around 14-21 dpi mature asexual spores are released, and the process starts again. This results in epidemic infections and is one reason why yield loss is so high. The hypothesis underpinning our planned research is that disruption of the very earliest events in infection e.g. Z. tritici spore germination, leaf penetration or initial hyphal development will prevent establishment of infection and initiation of disease. Thus targeting fungicide development to gene products essential for these developmental programs should deliver compounds that prevent disease and hence reduce yield loss. We have established a collaboration with Syngenta, a large Swiss based agribusiness to address our principle aim, which is to characterize the early events (0-4 dpi) in establishment of infection and initiation of disease by Z. tritici on wheat. Specifically we will: (1) Define the genes that are switched on by Z. tritici spores as they germinate on and initiate infection in the compatible wheat cultivar Avalon. This will provide a catalogue of genes that play a role in the initiation of disease, and that will be characterized in this project; (2) Characterize the cellular biology of both Z. tritici and wheat during early infection, and thus link specific genes to defined infection stages; (3) Undertake a combined bioinformatics and modelling assessment to prioritize Z. tritici genes involved in early infection for further analysis. This will allow us to select one hundred genes for analysis and (4) we will determine where the proteins encoded by the 100 genes are located within the fungus during infection. We will then inactivate each in turn and determine if this blocks infection, and if so at what stage? If lack of a protein results in the inability to cause infection then this protein has potential as a target for fungicide development.Taken together these experiments will not only reveal substantial new biology they will also identify proteins that can be utilized for rational target selection within the context of fungicide discovery.

为地球上的所有人提供足够的食物是人类在21世纪面临的一个重大问题。随着地球人口超过60亿，增加水稻、小麦、香蕉等主食作物的产量是真实的。到2030年，随着人口增长到预计的90亿，需求将更高。在英国，小麦是主要作物，2013年产量为1210万吨，价值超过15亿英镑。然而，真菌病，特别是由发酵壳针孢菌引起的三孢壳针孢斑点病（STB），是生产的主要限制。在未经处理的试验中，平均损失20%的产量，在某些情况下，田间损失达50%。控制这种疾病可以为英国小麦收成额外贡献240 - 600万吨，如果应用于2013年的全球小麦收成，将为粮食供应额外提供1.4亿吨。毫无疑问，STB是对全球粮食安全的严重和直接威胁，迫切需要新的控制措施。以Z.落在叶子表面并发芽，开始发病过程。随后是极化生长发育和进入叶的内部，通常在12小时内。在感病小麦品种中，感染后两天（dpi）真菌已经产生侧向分枝，并且在6- 8dpi时，这已经发展为在进入点下方限定大面积。在这个阶段，真菌还没有侵入小麦细胞，在植物上几乎看不到明显的真菌学。然而，8-10 dpi症状开始出现，伴随着初期无性生殖结构的发育、植物细胞的死亡和向寄生生长的转变。大约14-21 dpi成熟的无性孢子被释放，并且该过程再次开始。这导致了流行病的感染，也是产量损失如此之高的原因之一。支持我们计划研究的假设是，感染中最早期事件的中断，例如Z。孢子萌发、叶片穿透或初始菌丝发育将阻止感染的建立和疾病的开始。因此，将杀真菌剂的开发目标定位于这些开发计划所必需的基因产物，应该能够提供预防疾病的化合物，从而减少产量损失。我们已经与瑞士大型农业综合企业先正达建立了合作关系，以实现我们的主要目标，即表征Z.小麦上的小麦。具体来说，我们将：（1）定义由Z开启的基因。当它们在相容的小麦栽培品种Avalon上发芽并开始侵染时，它们会感染三孢孢子。这将提供一个目录的基因，在疾病的启动中发挥作用，并将在本项目的特点：（2）表征的细胞生物学的Z。在感染早期，将特定基因与确定的感染阶段联系起来;（3）进行生物信息学和建模评估相结合，优先考虑Z。与早期感染有关的三个基因，以便进一步分析。这将使我们能够选择100个基因进行分析，并且（4）我们将确定在感染期间由100个基因编码的蛋白质在真菌内的位置。然后，我们将依次对每种方法进行验证，并确定这是否会阻止感染，如果是，在什么阶段？如果缺乏蛋白质导致不能引起感染，则该蛋白质具有作为杀真菌剂开发的靶点的潜力。这些实验将不仅揭示大量的新生物学，还将鉴定可用于杀真菌剂发现背景下的合理靶点选择的蛋白质。