Phytochrome and pheromone signalling during the induction of a new cell type involved in sexual fusion in filamentous fungi

丝状真菌有性融合过程中诱导新细胞类型过程中的光敏色素和信息素信号传导

• 批准号: BB/F013574/1
• 负责人: Nick Read
• 金额: $ 62.04万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF013574%2F1
• 关键词: Phytochrome; pheromone; signalling; during; induction

The asexual spore produced by filamentous ascomycete fungi is called a conidium. The ascomycetes are the largest group of fungi and contain the majority of crop and human fungal pathogens. Conidia are the main reproductive cells and dispersal agents of these organisms, but can also act as male fertilizing agents during sexual reproduction. We have discovered that conidia of the model ascomycete fungus, Neurospora crassa, can produce three types of filamentous cells: (a) the conidial germ tube which is involved in colony establishment, (b) the conidial anastomosis tube which is involved in forming complex cellular networks by undergoing cell fusion, and (c) the most recently discovered conidial sex tube which is involved in sexual fusion with cells of the opposite sex. The mechanism by which conidial sex tubes are produced, and particularly how they are regulated by sex pheromones and by light, is the focus of the research in the present proposal. One interesting aspect is that the conidial sex tubes are formed on the side closest to the light source (i.e. they exhibit a positive phototropism). The first objective of our research proposal will be to analyse the role of pheromone signalling. In particular, we will determine whether a synthetic sex pheromone can induce conidial sex tubes to form. We have found that conidial sex tubes are formed in response to red light and this involves two red light photoreceptors called phytochromes. Our second objective will be to analyse how these phytochrome receptors respond to red light, and in doing so, regulate the formation of conidial sex tubes. Neurospora crassa was the first filamentous fungus to have its genome completely sequenced and as a result has been shown to possess ~ 10,000 genes. Each of Neurospora's ~ 10,000 genes is being mutated to produce 'knockout mutants. Our third objective will be to screen several hundred of these knockout mutants to determine if they are defective in conidial sex tube formation and/or phototropism. We have also obtained evidence that two other photoreceptors are involved in the formation of conidial sex tubes: a blue light photoreceptor called cryptochrome, and a green light photoreceptor belonging to the opsin family of proteins (which also includes the photoreceptor rhodopsin which is found in the human eye). The roles of these photoreceptors in fungi are currently unknown. Our fourth objective will be to analyse the roles of cryptochrome and two different opsins in the formation of conidial sex tubes and possibly their phototropic growth. The fifth objective will involve visualizing the phytochrome, cryptochrome and opsin photoreceptors by tagging them with fluorescent labels which allow them to be imaged in living cells with a fluorescence microscope. In this way we will be able to directly monitor whether they change their subcellular location in response to light exposure. Our final objective will be to be to determine if the different photoreceptors interact and act in concert in response to the light signals that result in the formation and phototropism of conidial sex tubes.

丝状果糖真菌产生的无性孢子称为分生孢子。子宫菌是最大的真菌群体，其中大部分作物和人类真菌病原体。分生孢子是这些生物的主要生殖细胞和分散剂，但在性繁殖过程中也可以充当男性施肥剂。我们已经发现，模型的Comycete真菌（Neurospora crassa）可以产生三种类型的丝状细胞：（a）涉及菌落建立的分生孢子细胞管，（b）分生孢子antastomisois tube涉及的分生孢子antastomisois cons涉及细胞的复杂细胞网络，该细胞与最近发现的性化对比有关，并与最终发现的性化为相互作用的对立性，该细胞涉及对异性群体的性能构成。生产性别管产生的机制，尤其是如何通过性信息素调节它们，这是本提案中研究的重点。一个有趣的方面是，分生孢子性管形成在最接近光源的一侧（即它们表现出阳性的光质主义）。我们研究建议的第一个目标是分析信息素信号的作用。特别是，我们将确定合成性信息素是否可以诱导分生孢子性管形成。我们发现，分子性管是根据红光而形成的，这涉及两个称为植物色素的红光光感受器。我们的第二个目标是分析这些植物感受器受体如何对红光做出反应，并在此过程中调节分生孢子的形成。 Neurospora crassa是第一个对其基因组完全测序的丝状真菌，因此已证明具有约10,000个基因。神经孢子的每个约10,000个基因都被突变以产生敲除突变体。我们的第三个目标是筛选数百种此类敲除突变体，以确定它们在分生孢子性管的形成和/或光质主义中是否有缺陷。我们还获得了证据表明，另外两个感光体参与了分生孢子性管的形成：一种称为Cryctodochrome的蓝光光感受器，以及属于Opsin蛋白蛋白家族的绿光光感受器（还包括在人眼中发现的光感受器Rhopoptor rohopeptor ohotoppoptor ropoptor）。这些光感受器在真菌中的作用目前尚不清楚。我们的第四个目标是分析加密斑块和两种不同的Opsin在形成分生孢子性管以及可能的光粒子生长中的作用。第五个目标将涉及通过用荧光标签标记植物色素，加密色素和Opsin光感受器，从而使它们在具有荧光显微镜的活细胞中成像。通过这种方式，我们将能够直接监视他们是否会因响应光曝光而改变其亚细胞位置。我们的最终目标是确定不同的光感受器是否相互作用并响应导致分生孢子性管的形成和光质主义的光信号。