Harnessing the microbiome for turtle conservation: investigating the protective effects of the eggshell microbiome against the emerging fungal disease Fusariosis using the yellow-spotted Amazon river turtle as a model system

利用微生物群保护海龟：以黄斑亚马逊河龟为模型系统，研究蛋壳微生物群对新出现的真菌病镰孢菌病的保护作用

• 批准号: 517884764
• 负责人: Professorin Dr. Simone Sommer
• 金额: --
• 依托单位: Institut für Evolutionsökologie und Naturschutzgenomik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/517884764?language=en
• 关键词: Harnessing; microbiome; turtle; conservation; investigating

The emergence of fungal pathogens threatening wildlife has increased exponentially, in part driven by emerging infectious diseases that are exacerbated by habitat degradation, pollution, and wildlife trade. Whilst catastrophic declines in amphibians and bats due to emerging fungal pathogens has been well documented, high mortality in sea turtles due to the emerging fungal disease Fusariosis has received less attention. This emerging disease is caused by the group of related pathogens in the Fusarium solani species complex (FSSC), involved in mass mortality of all seven sea turtle species by infecting turtle eggs during incubation and causing hatching failure. Alarmingly, this pathogen was recently detected in the Yellow-spotted Amazonian river turtle (Podocnemis unifilis) in the Ecuadorian Amazon, suggesting that this pathogen may also pose a threat to the 357 species of freshwater turtles and tortoises, many of which are already endangered. However, despite the imminent threat this emerging pathogen poses towards turtle biodiversity, we have very little understanding of this fungal disease, including its transmission dynamics, pathogenicity, and long-term fitness effects on turtle hosts. To address this gap, we propose to investigate Fusarium disease dynamics using P. unifilis as a model system. This species is part of a conservation program run by the Tipuni Biodiversity Station/Amazon since 2002, whereby eggs are collected at the point of laying and hatchlings are reared in captivity before being released, to avoid overharvesting of eggs for consumption and the illegal pet trade. Along this line, we will investigate the environmental and maternal sources of Fusarium infection at the point of laying and monitor eggs in captivity to characterise pathogenicity and infection development. Moreover, we will examine how habitat degradation due to palm oil agriculture alters Fusarium prevalence and pathogenicity. Lastly, we will test the role of the eggshell microbiome, which has recently been linked to Fusarium resistance, in mediating infection outcome and hatching success, with an aim of identifying eggshell microbes that can be harnessed for turtle conservation. Our knowledge about the development and assembly of the egg microbiome is limited to avian species and these mechanisms do not apply to turtles due to differences in parental care strategies between birds and turtles. Studies about the transmission and development of the egg bacterial and fungal microbiome in oviparous reptiles without parental care like turtles and their functional role in mediating pathogen resistance are missing. Together, these lines of research will considerably expand our understanding of Fusarium as an emerging infectious disease and the role of host-microbiome interactions for turtle health, thereby contributing to the development of effective turtle conservation strategies in the face of an emerging and potentially devastating threat.

威胁野生动物的真菌病原体的出现呈指数增长，部分原因是由于栖息地退化、污染和野生动物贸易加剧了新出现的传染病。虽然由于新出现的真菌病原体导致两栖动物和蝙蝠的灾难性下降已经得到了充分的记录，但由于新出现的真菌疾病镰孢菌病导致海龟的高死亡率却很少受到关注。这种新出现的疾病是由茄枯菌种复合体（Fusarium solani species complex， FSSC）中的一组相关病原体引起的，通过在孵化期间感染海龟卵并导致孵化失败，导致所有7种海龟的大量死亡。令人震惊的是，最近在厄瓜多尔亚马逊河流域的亚马逊河黄斑龟（Podocnemis unifilis）中发现了这种病原体，这表明这种病原体也可能对357种淡水龟和陆龟构成威胁，其中许多已经濒临灭绝。然而，尽管这种新出现的病原体对海龟的生物多样性构成了迫在眉睫的威胁，但我们对这种真菌疾病的了解甚少，包括它的传播动力学、致病性和对海龟宿主的长期适应性影响。为了解决这一差距，我们建议使用统一镰刀菌作为模型系统来研究镰刀菌的疾病动力学。自2002年以来，这一物种是蒂普尼生物多样性站/亚马逊开展的保护计划的一部分，该计划在产卵时收集鸡蛋，在孵化后放生，以避免过度收获用于消费和非法宠物贸易。沿着这条路线，我们将在产卵时调查镰刀菌感染的环境和母体来源，并监测圈养鸡蛋，以确定致病性和感染发展的特征。此外，我们将研究棕榈油农业导致的栖息地退化如何改变镰刀菌的患病率和致病性。最后，我们将测试蛋壳微生物组在介导感染结果和孵化成功方面的作用，蛋壳微生物组最近与镰刀菌抗性有关，目的是确定可以用于海龟保护的蛋壳微生物。我们对蛋微生物群的发育和组装的了解仅限于鸟类，由于鸟类和海龟之间亲代护理策略的差异，这些机制并不适用于海龟。关于龟等无亲代照顾的卵生爬行动物的卵细菌和真菌微生物群的传播和发育及其在介导病原体抗性中的功能作用的研究尚缺乏。总之，这些研究将大大扩展我们对镰刀菌病作为一种新兴传染病的理解，以及宿主-微生物组相互作用对海龟健康的作用，从而有助于在面对新出现的潜在破坏性威胁时制定有效的海龟保护策略。