Ecology and evolution of the mycorrhizal mutualism in a changing environment

变化环境中菌根互利共生的生态学和进化

• 批准号: RGPIN-2018-04620
• 负责人: Maherali, Hafiz
• 金额: $ 4.01万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=757633
• 关键词: Ecology; evolution; mycorrhizal; mutualism; changing

Biologists seeks to explain why organisms have evolved so many different forms and functions, and to explain how this diversity influences the assembly and functioning of ecological communities. Climate and antagonistic interactions such as competition and predation have long been studied as causes of evolutionary and ecological change, but less well appreciated, though just as common, are mutualisms, in which partners exchange resources and services for mutual benefit. Nearly all organisms engage in one or more mutualisms, and it is predicted that without these interactions, the earth would support far fewer species. The interaction between plants and root inhabiting mycorrhizal fungi is one of the most ancient and widespread mutualisms in nature, evolving more than 400 million years ago. Nearly all plants are colonized by these fungi, who increase plant access to soil nutrients, particularly phosphorus, in exchange for sugars from photosynthesis. Though characterized as a mutualism, plant responses to fungal inoculation are quite variable, ranging from neutrality to a 100-fold stimulation of plant growth. The proposed research will experimentally test why the mutualism between plants and mycorrhizal fungi varies in nature, and how this variability affects the diversity and function of plant communities. First, we will identify the environmental factors that cause evolutionary change in the mutualism using a controlled natural selection experiment. Second, we will test whether divergence in the strength of the mutualism has consequences for population dynamics and species co-existence. Third, we will test whether widespread deposition of nitrogen from human activities, which creates acute phosphorus limitation, causes plant populations to evolve a stronger mutualism with mycorrhizal fungi, and then test whether this evolution influences nutrient cycling.The proposed research will be the first to experimentally identify the environmental causes of evolution in the mycorrhizal mutualism. Identifying these causes will enable us to predict how mutualisms will evolve in response to anthropogenic effects on climate and resource availability. By testing how the strength of a mutualism influences species co-existence, we will causally link mutualism with processes that maintain biodiversity. The research will contribute key insights into how dramatic increases in nitrogen deposition influence the evolution and ecological effects of a dominant mutualism. Knowledge of these effects is important because they are not presently considered in forecasts of how anthropogenic change will affect ecosystem function. The proposed research will provide undergraduate and graduate students with opportunities to develop strong analytical, project management and communication skills required for both scientific research and problem solving in the public and private sector.

生物学家试图解释为什么生物体进化出如此多不同的形式和功能，并解释这种多样性如何影响生态群落的组成和功能。气候和对抗的相互作用，如竞争和捕食，长期以来一直被研究为进化和生态变化的原因，但不太受重视的是，尽管同样普遍，互惠关系，在这种关系中，合作伙伴交换资源和服务以实现互利。几乎所有的生物都参与一种或多种相互作用，据预测，如果没有这些相互作用，地球上的物种将会少得多。植物和根菌根真菌之间的相互作用是自然界中最古老、最广泛的相互作用之一，它在4亿多年前就已经进化出来了。几乎所有的植物都是这些真菌的殖民地，它们增加了植物对土壤养分的获取，尤其是磷，以换取光合作用产生的糖。虽然真菌接种是一种相互作用，但植物对真菌接种的反应变化很大，从中性到100倍的植物生长刺激不等。本研究将通过实验研究植物与菌根真菌之间的共生关系在自然界中为何会发生变化，以及这种变化如何影响植物群落的多样性和功能。首先，我们将利用受控的自然选择实验确定导致共生进化变化的环境因素。其次，我们将检验互利共生强度的差异是否对种群动态和物种共存产生影响。第三，我们将测试来自人类活动的氮的广泛沉积是否会导致植物种群与菌根真菌进化出更强的共生关系，从而造成急性磷限制，然后测试这种进化是否会影响养分循环。提出的研究将是第一个实验确定菌根共生进化的环境原因。确定这些原因将使我们能够预测共生关系在应对气候和资源可用性的人为影响时将如何演变。通过测试互惠共生的强度如何影响物种共存，我们将把互惠共生与维持生物多样性的过程因果联系起来。这项研究将对氮沉降的急剧增加如何影响显性互惠共生的进化和生态效应提供关键见解。了解这些影响很重要，因为目前在预测人为变化将如何影响生态系统功能时还没有考虑到这些影响。拟议的研究将为本科生和研究生提供机会，培养在公共和私营部门进行科学研究和解决问题所需的强大分析、项目管理和沟通技巧。