Syntrophic Oxidation of Propionate in Rice Field Soil at 15 and 30°C under Methanogenic Conditions
Syntrophic Oxidation of Propionate in Rice Field Soil at 15 and 30°C under Methanogenic Conditions
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DOI：
10.1128/aem.00688-12
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发表时间：
2012-07-01
影响因子：
4.4
通讯作者：
Lu, Yahai
中科院分区：
文献类型：
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作者：
Gan, Yanlu;Qiu, Qiongfen;Lu, Yahai
丙酸盐是湿地和稻田有机物厌氧分解的主要中间产物之一。在产甲烷条件下，丙酸通过质子还原和丙酸氧化细菌与H-2消耗产甲烷菌之间的互养相互作用而分解。温度是一个重要的环境调节器，但其对互养丙酸氧化的影响知之甚少。在本研究中，我们研究了稻田土壤中丙酸盐在15 ℃和30 ℃下的互养氧化。将[U-C-13]丙酸盐（99原子%）施加到缺氧土壤泥浆中，并通过基于DNA的稳定同位素探针追踪同化C-13的细菌和古菌。互养菌属，Pelotomaculum属，和Smithella spp.发现在30 ℃下孵育[C-13]丙酸盐后，C-13显著掺入其核酸中。Smithella spp.后期增加，并同时为互养单胞菌属。增加在30 ℃时，产甲烷菌属Methanosaetaceae、氢营养型Methanomicrobiales和Methanocellales是产甲烷菌的伙伴.丙酸盐的互养氧化也在15 ℃时活跃地发生。互养虫属C-13显著标记，而Pelotomaculum spp.在这个温度下不太活跃此外，甲烷微生物目、甲烷胞菌目和甲烷菌科在产甲烷群落中占主导地位，而甲烷菌科减少。温度显著影响稻田土壤中丙酸盐降解互养功能团的活性和群落结构。有趣的是，Geopathy spp.而其他一些厌氧生物如红环菌科、酸杆菌、放线菌和热微生物可能也同化了丙酸盐衍生的C-13。这些生物体参与的机制仍不清楚。
Propionate is one of the major intermediary products in the anaerobic decomposition of organic matter in wetlands and paddy fields. Under methanogenic conditions, propionate is decomposed through syntrophic interaction between proton-reducing and propionate-oxidizing bacteria and H-2-consuming methanogens. Temperature is an important environmental regulator; yet its effect on syntrophic propionate oxidation has been poorly understood. In the present study, we investigated the syntrophic oxidation of propionate in a rice field soil at 15 degrees C and 30 degrees C. [U-C-13]propionate (99 atom%) was applied to anoxic soil slurries, and the bacteria and archaea assimilating C-13 were traced by DNA-based stable isotope probing. Syntrophobacter spp., Pelotomaculum spp., and Smithella spp. were found significantly incorporating C-13 into their nucleic acids after [C-13]propionate incubation at 30 degrees C. The activity of Smithella spp. increased in the later stage, and concurrently that of Syntrophomonas spp. increased. Aceticlastic Methanosaetaceae and hydrogenotrophic Methanomicrobiales and Methanocellales acted as methanogenic partners at 30 degrees C. Syntrophic oxidation of propionate also occurred actively at 15 degrees C. Syntrophobacter spp. were significantly labeled with C-13, whereas Pelotomaculum spp. were less active at this temperature. In addition, Methanomicrobiales, Methanocellales, and Methanosarcinaceae dominated the methanogenic community, while Methanosaetaceae decreased. Collectively, temperature markedly influenced the activity and community structure of syntrophic guilds degrading propionate in the rice field soil. Interestingly, Geobacter spp. and some other anaerobic organisms like Rhodocyclaceae, Acidobacteria, Actinobacteria, and Thermo-microbia probably also assimilated propionate-derived C-13. The mechanisms for the involvement of these organisms remain unclear.