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Microbial degradation of isoprene in the terrestrial environment

陆地环境中异戊二烯的微生物降解

基本信息

批准号：
NE/J009725/1
负责人：
John Murrell
金额：
$ 45.54万
依托单位：
University of East Anglia
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%2FJ009725%2F1
关键词：
Microbial degradation isoprene terrestrial environment

项目摘要

The Blue Mountains in Australia and Blue Ridge Mountains of Virginia, are so-named because of the blue haze that results from atmospheric reactions with isoprene, a gas produced in abundance by plants and especially many tree species. Trees that are starting to be grown widely as a source of bioenergy, namely willow and poplar, are among the highest isoprene emitters. Isoprene protects plants against heat and light-induced damage, and can also serve as a signaling molecule. Isoprene is so reactive with other chemicals in the lower atmosphere that it limits their capacity to react with methane and also generates ozone. Both ozone and methane are potent greenhouse gases, and ozone impairs plant growth. On the more positive side, isoprene can indirectly stimulate cloud formation which provides a cooling effect. Hundreds of studies have investigated isoprene production, primarily from trees, and examined the effect of a changing environment on its flux from tree to atmosphere. In stark contrast, only a handful of studies have shown that microbes in the soil consume isoprene, and a few of those microbes have been grown in the laboratory. Microbes are abundant (several billion per teaspoon of soil and more than a million per square cm of leaf) and the most important catalysts for cycling chemicals in the environment. We know from studying the cycles of other climatically important gases, like methane, that microbial consumption is an extremely important process that is greatly influenced by climate change. From hundreds of methane-consuming bacteria in culture, we have extensive knowledge of their metabolic pathways, which allows the development of investigative tools to help inform land-use management decisions. For isoprene, which is produced in similar abundance to methane, we lack this knowledge and tools.Therefore, in addition to those bacteria that we already have in culture, we propose to culture isoprene-degrading microbes, focusing on soil and leaf inhabitants. Using powerful genomic-based techniques, we will determine the DNA sequences of the genes involved in isoprene degradation. Additionally, we will use tools developed by the PI to identify and investigate those isoprene degraders that are not easy to grow. Most bacteria look alike and so we frequently use DNA sequences to study their roles in nature. Selected unique DNA sequences will be used to identify, view and count key species of isoprene-degrading bacteria in natural samples. This will enable us to determine precisely where they live, e.g. we envisage that they will be especially abundant around stomata (pores in the leaf) from where most isoprene escapes; and the use of state-of-the art imaging techniques (developed by our project partner) will allow us to identify which individual microbes are actively degrading isoprene in the soil or on the leaf surface.Complementing this study, a PhD student will measure isoprene consumption in forest soils, and for the first time, on leaves from various tree species, comparing isoprene emitters with non-emitters as well as sun and shade leaves. We will test whether adding permutations of isoprene-degrading microbes to leaf surfaces enhances consumption, and by measuring the microbes' ability to survive or grow on the leaves, we will obtain insights into whether this is a potential strategy for reducing isoprene flux. All of the data emanating from this project will be valuable for management of natural woodlands and bioenergy crops, in relation to greenhouse gas emissions.

澳大利亚的蓝山和弗吉尼亚州的蓝岭山脉之所以如此命名，是因为异戊二烯与大气反应产生的蓝色烟雾，异戊二烯是一种由植物特别是许多树种产生的丰富气体。作为生物能源来源的树木开始广泛种植，即杨柳和白杨，是异戊二烯排放量最高的树木。异戊二烯可以保护植物免受热和光诱导的伤害，也可以作为一种信号分子。异戊二烯与低层大气中的其他化学物质反应性很强，限制了它们与甲烷反应的能力，并产生臭氧。臭氧和甲烷都是强有力的温室气体，臭氧会损害植物的生长。从更积极的方面来看，异戊二烯可以间接刺激云的形成，从而提供冷却效果。数以百计的研究调查了异戊二烯的生产，主要是从树木，并检查了环境变化对其从树木到大气的通量的影响。与此形成鲜明对比的是，只有少数研究表明土壤中的微生物消耗异戊二烯，其中一些微生物已经在实验室中生长。微生物是丰富的（每茶匙土壤中有几十亿，每平方厘米树叶中有一百多万），是环境中化学物质循环的最重要催化剂。我们从研究其他对气候有重要影响的气体（如甲烷）的循环中得知，微生物的消耗是一个极其重要的过程，受气候变化的影响很大。从培养的数百种甲烷消耗细菌中，我们对它们的代谢途径有了广泛的了解，这使得研究工具的开发能够帮助为土地使用管理决策提供信息。异戊二烯的产量与甲烷相似，但我们缺乏相关知识和工具。因此，除了已经培养的细菌外，我们还打算培养降解异戊二烯的微生物，重点是土壤和树叶上的生物。使用强大的基因组技术，我们将确定参与异戊二烯降解的基因的DNA序列。此外，我们将使用PI开发的工具来识别和研究那些不容易生长的异戊二烯降解剂。大多数细菌看起来都很相似，所以我们经常使用DNA序列来研究它们在自然界中的作用。选定的独特DNA序列将用于识别、观察和计数天然样品中异戊二烯降解细菌的关键物种。这将使我们能够准确地确定它们生活在哪里，例如，我们设想它们将在气孔周围特别丰富（叶中的孔）从那里大多数异戊二烯逃逸;以及最先进的成像技术（由我们的项目合作伙伴开发）将使我们能够确定哪些微生物正在积极降解土壤或树叶表面的异戊二烯。补充这项研究，一名博士生将测量森林土壤中异戊二烯的消耗量，并首次测量不同树种的树叶中异戊二烯的消耗量，比较异戊二烯排放者与非排放者以及阳光和阴影下的树叶。我们将测试在叶子表面添加异戊二烯降解微生物的排列是否会增加消耗，并通过测量微生物在叶子上生存或生长的能力，我们将深入了解这是否是减少异戊二烯通量的潜在策略。该项目产生的所有数据对于管理天然林地和生物能源作物的温室气体排放都将是宝贵的。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Draft Genome Sequences of Three Terrestrial Isoprene-Degrading Rhodococcus Strains.

DOI：
10.1128/genomea.01256-17
发表时间：
2017-11-09
期刊：
Genome announcements
影响因子：
0
作者：
Crombie AT;Emery H;McGenity TJ;Murrell JC
通讯作者：
Murrell JC

'Omics-guided prediction of the pathway for metabolism of isoprene by Variovorax sp. WS11.

DOI：
10.1111/1462-2920.16149
发表时间：
2022-11
期刊：
ENVIRONMENTAL MICROBIOLOGY
影响因子：
5.1
作者：
Dawson, Robin A.;Rix, Gregory D.;Crombie, Andrew T.;Murrell, J. Colin
通讯作者：
Murrell, J. Colin

Regulation of plasmid-encoded isoprene metabolism in Rhodococcus, a representative of an important link in the global isoprene cycle.

DOI：
10.1111/1462-2920.12793
发表时间：
2015-09
期刊：
Environmental microbiology
影响因子：
5.1
作者：
Crombie AT;Khawand ME;Rhodius VA;Fengler KA;Miller MC;Whited GM;McGenity TJ;Murrell JC
通讯作者：
Murrell JC

Gene probing reveals the widespread distribution, diversity and abundance of isoprene-degrading bacteria in the environment