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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/I026022/2
负责人：
Mark Hodson
金额：
$ 4.11万
依托单位：
University of York
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%2F2
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.

了解后生动物如何耐受由多种应激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、大面积持续脱气以及高温。土壤温度升高、氧气含量低、二氧化碳含量高以及土壤酸化对当地生物群来说是严峻的挑战。本提案将对生态相关、生态系统工程、土栖入侵性蚯蚓物种（Amynthas gracilis）对自然来源的物理化学应激物混合物的适应产生机械理解。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（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）中得到应用。富尔纳斯是亚速尔群岛圣米格尔岛的一个乡村教区，位于一座活火山的破火山口内。弗纳斯持续的火山活动使土壤面临三个威胁生命的严峻挑战：局部低氧气 (10%) 和高二氧化碳水平 (54%)、高温 (37oC) 以及由于土壤酸化 (pH 5.8) 而导致生物可利用的金属浓度升高。令人震惊的是，这种极端的土壤竟然能够养活小细线菌的种群。 [值得注意的是，二氧化碳浓度超过 17% 会导致暴露的人类在 1 分钟内死亡。] 该项目的目的是研究这种土栖多细胞动物如何耐受活跃火山土壤的恶劣条件的具体功能方面。我们将研究 A. gracilis 种群在三种不同情况下的分子和生理反应：i) 直接从不活跃和活跃的蚯蚓中取样火山土壤；ii) 将蚯蚓从活跃的火山移植到非活跃土壤的微观世界，反之亦然； iii) 一系列实验室“暴露”，代表该领域遇到的三种化学/物理挑战的每种组合（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，以对蚯蚓吸收的金属可用性进行建模。 - 分析基因表达，揭示蚯蚓如何调节其转录组，使其能够耐受活跃火山活动带来的严峻挑战。 - 对遗传数据进行计算询问，以识别与金属应激、耐热性、二氧化碳代谢和缺氧有关的功能上重要的目标基因的突变。- 测量称为“缺氧诱导因子”(HIF) 的保守基因的表达水平，先前的研究表明，该基因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。- 测量属于缺氧诱导因子的基因的表达应激反应伴侣的“热休克”超家族。-生化和生理测量，以确定 O2 穿过体壁运输的效率，以及血红蛋白的量和 O2 亲和力特性。 - 测量阿明萨斯 O2 消耗量和 ATP 生成率的昼夜变化，以确定其行为和生理机能是否在活跃的火山土壤中发生改变。同时，我们建议支持一名博士生确定亚速尔群岛和（通过合作）亚洲（老挝、韩国、泰国、华南）（该世界性物种的起源地区）的 A. gracilis 种群的遗传结构。该奖学金还将研究该生物体的繁殖，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的殖民者物种的影响。