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Stress in a hot place: Ecogenomics and phylogeography in a pantropical sentinel inhabiting multi-stressor volcanic soils

炎热地区的压力：居住在多压力源火山土壤中的泛热带哨兵的生态基因组学和系统发育地理学

基本信息

批准号：
NE/I026022/1
负责人：
Mark Hodson
金额：
$ 4.36万
依托单位：
University of Reading
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2012
资助国家：
英国
起止时间：
2012 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FI026022%2F1
关键词：
Stress hot place Ecogenomics phylogeography

项目摘要

Understanding of how any metazoan organism tolerates an extreme environment comprised of multiple stressors may help to predict the impacts of current and future multifaceted global change on biodiversity and ecological function. Active volcanic soils represent extreme environments with unique features: elevated metal-ion concentrations, constant degassing over a wide area, and high temperature. Elevated soil temperature, as well as low O2, high CO2, and acidified soil are inhospitable challenges to the resident biota. The present proposal will derive a mechanistic understanding of the adaptation of an ecologically-relevant, ecosytem engineering, soil-dwelling invasive earthworm species (Amynthas gracilis) to cocktails of physico-chemical stressors of natural origin. Furthermore, the observations on this metazoan life-form with extremophile traits will have applications in the bioeconomy (biotechnology, agriculture and vermicomposting), medicine (models for anoxia & hypercapnia), and environmental management (ecotoxicology, risk assessment, land reclamation). Furnas, a rural parish on São Miguel in the Azores, is situated inside a caldera of an active volcano. Persistent volcanic activity at Furnas creates a soil presenting three formidable life-threatening challenges: locally low O2 (10%) and high CO2 levels (54%), high temperatures (37oC), and elevated metal concentrations rendered bioavailable due to soil acidification (pH 5.8). It is astounding that this extreme soil supports a viable population of A. gracilis. [It is noteworthy that CO2 concentrations greater than 17% leads death within 1 minute in exposed humans.] The aim of this project is to investigate specific functional aspects of how this soil-dwelling multi-cellular animal tolerates the inhospitable conditions of active volcanic soils.We will investigate the molecular and physiological responses of populations of A. gracilis under three discrete scenarios:i) earthworms sampled directly from inactive and actively volcanic soils;ii) earthworms transplanted from volcanically active to microcosms located in non-active soils, and vice versa; and iii) a series of laboratory 'exposures' representing every combination of the three chemical/physical challenges encountered in the field (i.e. singular or combinatorial). Our observations will encompass the following: - Comprehensive soil analyses to allow modeling of metal availability for uptake by the earthworms. - Profiling gene expression to reveal how the earthworm regulates its transcriptome enabling it to tolerate the severe challenges presented by active volcanism. - Computational interrogation of genetic data to identify mutations in functionally significant target genes involved in metal stress, thermo-tolerance, CO2 metabolism, and hypoxia.- Measuring the expression level of a conserved gene known as "Hypoxia-Induced Factor" (HIF) which previous studies indicate is paramount in regulating responses to hypoxia, thermal stress, and metal toxicity in vertebrates.- Measuring the expression of genes belonging to the 'heat-shock' superfamily of stress-response chaperones.- Biochemical and physiological measurements to determine the efficiency of O2 transport across the body wall, and the amount and O2-affinity properties of the haemoglobin. - Measuring diurnal changes in the O2 consumption and ATP production rates of Amynthas to establish whether behavior and physiology are modified in active volcanic soils.In parallel, we propose to support a PhD student to determine the genetic structure of A. gracilis populations in the Azores, and (through collaboration) in Asia (Laos, Korea, Thailand, South China), the region of origin of the cosmopolitan species. The studentship will also study the organism's reproduction, reported to be predominately asexual (parthenogenetic), and the implications of this for a species that is a successful invasive colonizer across a wide circum-tropical range.

了解任何后生动物生物如何耐受由多种压力源组成的极端环境可能有助于预测当前和未来多方面的全球变化对生物多样性和生态功能的影响。活跃的火山土壤代表了具有独特特征的极端环境：金属离子浓度升高，大面积持续脱气和高温。升高的土壤温度，以及低O2，高CO2和酸化的土壤对居民生物群是不适宜居住的挑战。本提案将得出一个机械的理解，适应生态相关的，生态系统工程，土壤居住的入侵物种（Amynthas gracilis）的鸡尾酒的物理化学压力的自然起源。此外，对这种具有极端微生物特征的后生动物生命形式的观察将在生物经济学（生物技术，农业和蚯蚓堆肥），医学（缺氧和高碳酸血症模型）和环境管理（生态毒理学，风险评估，土地复垦）中应用。Furnas是亚速尔群岛圣米格尔的一个乡村教区，位于一座活火山的破火山口内。Furnas持续的火山活动使土壤面临三大威胁生命的挑战：当地低O2（10%）和高CO2水平（54%），高温（37 ℃），以及由于土壤酸化（pH 5.8）而导致的高金属浓度。令人震惊的是，这种极端的土壤支持一个可行的人口A。股薄肌[It值得注意的是，CO2浓度大于17%会导致暴露于其中的人类在1分钟内死亡。本项目的目的是研究这种土壤多细胞动物如何耐受活火山土壤的恶劣条件的特定功能方面。在三种不同的情况下对gracilis进行了研究：i）直接从不活跃和活跃的火山土壤中取样的蚯蚓;ii）将蚯蚓从火山活跃土壤移植到位于非活跃土壤中的微宇宙中，反之亦然; iii）一系列实验室“暴露”，代表实地遇到的三种化学/物理挑战的每一种组合（即单一或组合）。我们的观察将包括以下内容：-全面的土壤分析，以便对蚯蚓吸收的金属可用性进行建模。- 分析基因表达以揭示火山是如何调节其转录组的，使其能够承受活火山活动带来的严峻挑战。- 遗传数据的计算询问，以确定涉及金属应激，耐热性，CO2代谢和缺氧的功能重要靶基因的突变。测量被称为“缺氧诱导因子”（HIF）的保守基因的表达水平，以前的研究表明，HIF在调节脊椎动物对缺氧，热应激和金属毒性的反应中至关重要。测量属于应激反应伴侣的“热休克”超家族的基因表达。生物化学和生理学测量，以确定O2穿过体壁的运输效率，以及血红蛋白的量和O2亲和性。- 测量昼夜变化的O2消耗量和ATP生产率的Amynthas，以确定是否行为和生理活性火山土壤中修改。gracilis种群在亚速尔群岛，并（通过合作）在亚洲（老挝，韩国，泰国，中国南部），该地区的原产地的世界性物种。该学生还将研究生物体的繁殖，据报道主要是无性繁殖（孤雌生殖），以及这对一个在广泛的环热带范围内成功入侵殖民者的物种的影响。