Regulation of plasmid-encoded isoprene metabolism in Rhodococcus, a representative of an important link in the global isoprene cycle.
Regulation of plasmid-encoded isoprene metabolism in Rhodococcus, a representative of an important link in the global isoprene cycle.
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DOI：
10.1111/1462-2920.12793
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发表时间：
2015-09
影响因子：
5.1
通讯作者：
Murrell JC
中科院分区：
文献类型：
--
作者：
Crombie AT;Khawand ME;Rhodius VA;Fengler KA;Miller MC;Whited GM;McGenity TJ;Murrell JC
生物源挥发性有机化合物（VOCs）的排放是全球碳循环的重要组成部分，占生态系统净生产力的很大一部分。它们影响大气化学，并直接和间接地产生温室气体。异戊二烯主要由植物排放，占挥发性有机化合物总量的三分之一，但与甲烷相比，甲烷的释放量相似，我们对它的生物降解知之甚少。在这里，我们报告的异戊二烯降解分离株，红球菌属AD45的基因组，并使用诱变表明，质粒编码的可溶性二铁中心异戊二烯单加氧酶（IsoMO）是必不可少的异戊二烯代谢。使用RNA测序（RNAseq）分析暴露于异戊二烯或环氧异戊二烯的细胞在底物转换时程实验中，我们发现，从22个连续的基因，包括那些编码IsoMO的转录本，高度上调，成为细胞中最丰富的，并包括超过25%的整个转录组。在野生型和IsoMO破坏突变株的基因转录分析表明，环氧异戊二烯，或异戊二烯代谢的后续产品，而不是异戊二烯本身，是诱导分子。我们为未来研究这种重要的气候活性化合物的环境生物消耗提供了分子数据的基础。
Emissions of biogenic volatile organic compounds (VOCs) form an important part of the global carbon cycle, comprising a significant proportion of net ecosystem productivity. They impact atmospheric chemistry and contribute directly and indirectly to greenhouse gases. Isoprene, emitted largely from plants, comprises one third of total VOCs, yet in contrast to methane, which is released in similar quantities, we know little of its biodegradation. Here, we report the genome of an isoprene degrading isolate, Rhodococcus sp. AD45, and, using mutagenesis shows that a plasmid-encoded soluble di-iron centre isoprene monooxygenase (IsoMO) is essential for isoprene metabolism. Using RNA sequencing (RNAseq) to analyse cells exposed to isoprene or epoxyisoprene in a substrate-switch time-course experiment, we show that transcripts from 22 contiguous genes, including those encoding IsoMO, were highly upregulated, becoming among the most abundant in the cell and comprising over 25% of the entire transcriptome. Analysis of gene transcription in the wild type and an IsoMO-disrupted mutant strain showed that epoxyisoprene, or a subsequent product of isoprene metabolism, rather than isoprene itself, was the inducing molecule. We provide a foundation of molecular data for future research on the environmental biological consumption of this important, climate-active compound.