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Host-parasite interaction in the endobiotic basal fungal lineage Nephridiophagidae and its insect host

内生基础真菌谱系肾病及其昆虫宿主中宿主与寄生虫的相互作用

基本信息

批准号：
397619173
负责人：
Privatdozentin Dr. Renate Radek
金额：
--
依托单位：
Arbeitsgruppe Rolff - Evolutionsbiologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/397619173?language=en
关键词：
Host parasite interaction endobiotic basal

项目摘要

Most fungal phyla contain entomopathogenic lineages with different degrees of specificity. A highly specialized but hardly studied group are the unicellular nephridiophagids, endobiotic fungi that infect the Malpighian tubules of insects. Here we want to investigate their effect on the fitness of their hosts. Our hypothesis is that the fitness of Nephridiophaga-infected hosts is reduced. Different fitness components will be tested, including reproductive success, physical fitness, and physiological fitness correlates such as immunocompetence, functionality of the Malpighian tubules, and susceptibility to chemical insecticides. The German cockroach Blattella germanica is an ideal test organism for our experiments. Sterile washing of the egg-cases enables production of parasite-free populations which can be specifically infected with Nephridiophaga by feeding parasitized Malpighian tubules. Further, the short development time and quick reproduction ensures the production of sufficient numbers of animals. This also facilitates experiments concerning population development and reproductive success. In a second part we want to unravel the life cycle of the endobionts and also establish the phylogenetic relationships. The early life stages which develop from orally ingested spores of Nephridiophaga are completely unknown. We hypothesize that the hatched sporoplasms are motile and actively pass through the gut wall and haemolymph to infect the final habitat, i.e. the Malpighian tubules. In-vitro experiments using different physical and chemical stimuli will be performed to induce hatching of the sporoplasm from the spore. Aspects of motility are observed by light microscopy (e.g. time lapse video microscopy, fluorescence immune staining of cytoskeleton). The early in-situ development will be studied after oral infection or after injection of spores into the haemolymph (e.g. whole mount gut preparations with fluorescent stains, PCR for detection of low numbers of Nephridiophaga). A further point of emphasis is to deepen the molecular phylogenetic studies of nephridiophagids in order to find the exact position within the early diverging fungal groups. Recent results support that nephridiophagids may represent a new basal fungal phylum close to the Chytridiomycota s.l. For a well-supported reconstruction of the phylogenetic tree it is necessary to analyze more nephridiophagid species and use more genetic markers.

大多数真菌门含有具有不同程度特异性的昆虫病原谱系。单细胞噬肾菌是一个高度专业化但几乎没有研究的群体，它们是感染昆虫马氏小管的内生真菌。在这里，我们想研究它们对宿主健康的影响。我们的假设是，被肾噬菌感染的宿主的适应性降低了。将测试不同的健康成分，包括生殖成功、身体健康和生理健康相关性，例如免疫能力、马尔皮基小管的功能以及对化学杀虫剂的敏感性。德国小蠊（Blattella germanica）是我们实验的理想测试生物。对卵壳进行无菌清洗可以产生无寄生虫的群体，这些群体可以通过喂养寄生的马氏小管来特异性感染肾噬菌体。此外，较短的发育时间和快速的繁殖确保了足够数量的动物的生产。这也有利于有关人口发展和繁殖成功的实验。在第二部分中，我们想要阐明内生生物的生命周期并建立系统发育关系。从口服食肾孢子发育而来的早期生命阶段是完全未知的。我们假设孵化的孢子质是能动的，并主动穿过肠壁和血淋巴感染最终的栖息地，即马尔皮基小管。将进行使用不同物理和化学刺激的体外实验以诱导孢子孵化出孢子质。通过光学显微镜观察运动性方面（例如延时视频显微镜、细胞骨架的荧光免疫染色）。将在口腔感染后或将孢子注射到血淋巴后研究早期原位发育（例如带有荧光染色的整体肠道制剂，用于检测少量食肾菌的 PCR）。进一步的重点是深化噬肾菌的分子系统发育研究，以便找到早期分化真菌类群中的确切位置。最近的结果支持噬肾菌可能代表一种与壶菌门 (Chytridiomycota s.l) 接近的新基础真菌门。为了对系统发育树进行有充分支持的重建，有必要分析更多的食肾动物物种并使用更多的遗传标记。