Identification of iron-reducing microorganisms in anoxic rice paddy soil by 13C-acetate probing
Identification of iron-reducing microorganisms in anoxic rice paddy soil by 13C-acetate probing
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DOI：
10.1038/ismej.2009.100
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发表时间：
2010-02-01
期刊：
影响因子：
11
通讯作者：
Friedrich, Michael W.
中科院分区：
文献类型：
--
作者：
Hori, Tomoyuki;Mueller, Alexandra;Friedrich, Michael W.
在缺氧稻田土壤中，三价铁还原是最重要的末端电子接受过程之一，但对铁还原微生物的身份知之甚少。在这里，我们在氧化铁 (III) 作为电子受体的情况下，通过基于 RNA 的稳定同位素探测来鉴定醋酸盐代谢细菌。内源铁 (III) 还原 21 天后，使用 C-13 标记的乙酸盐 (2 mM) 和添加的三价铁氧化物（水铁矿或针铁矿）在稻田土壤浆液中进行同位素探测 48 和 72 小时。水铁矿的减少与产甲烷作用的强烈抑制同时发生（77%）。从每次处理中提取的 RNA 通过等密度离心进行密度解析，并通过末端限制性片段长度多态性进行分析，然后对细菌和古细菌群体的 16S rRNA 进行克隆和测序。在水铁矿处理的重同位素标记 RNA 中，主要的 C-13 同化菌群被鉴定为地杆菌属 (Geobacter spp)。 （类似于所有克隆的 85%）。在针铁矿处理中，未检测到铁(II) 的形成。然而，地杆菌属。 （类似于 30%），δ-变形菌厌氧粘杆菌属。 （接近 30%），并且新型 β-变形菌在重 rRNA 组分中占主导地位，表明 C-13-乙酸盐在针铁矿存在下已被同化，而在对照重 RNA 中未检测到任何物质。首次将活性乙酸盐氧化铁（III）还原细菌（包括迄今为止尚未识别的新菌群）确定为缺氧稻田土壤中的功能群。 ISME 期刊 (2010) 4, 267-278； doi：10.1038/ismej.2009.100； 2009 年 9 月 24 日在线发布
In anoxic rice field soil, ferric iron reduction is one of the most important terminal electron accepting processes, yet little is known about the identity of iron-reducing microorganisms. Here, we identified acetate-metabolizing bacteria by RNA-based stable isotope probing in the presence of iron(III) oxides as electron acceptors. After reduction of endogenous iron(III) for 21 days, isotope probing with C-13-labeled acetate (2 mM) and added ferric iron oxides (ferrihydrite or goethite) was performed in rice field soil slurries for 48 and 72 h. Ferrihydrite reduction coincided with a strong suppression of methanogenesis (77%). Extracted RNA from each treatment was density resolved by isopycnic centrifugation, and analyzed by terminal restriction fragment length polymorphism, followed by cloning and sequencing of 16S rRNA of bacterial and archaeal populations. In heavy, isotopically labeled RNAs of the ferrihydrite treatment, predominant C-13-assimilating populations were identified as Geobacter spp. (similar to 85% of all clones). In the goethite treatment, iron(II) formation was not detectable. However, Geobacter spp. (similar to 30%), the delta-proteobacterial Anaeromyxobacter spp. (similar to 30%), and novel beta-Proteobacteria were predominant in heavy rRNA fractions indicating that C-13-acetate had been assimilated in the presence of goethite, whereas none were detected in the control heavy RNA. For the first time, active acetate-oxidizing iron(III)-reducing bacteria, including novel hitherto unrecognized populations, were identified as a functional guild in anoxic paddy soil. The ISME Journal (2010) 4, 267-278; doi: 10.1038/ismej.2009.100; published online 24 September 2009