Syntrophic growth with direct interspecies electron transfer between pili-free Geobacter species
Syntrophic growth with direct interspecies electron transfer between pili-free Geobacter species
复制标题
无菌毛地杆菌种之间直接种间电子转移的共养生长
DOI：
10.1038/s41396-018-0193-y
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发表时间：
2018-09-01
期刊：
影响因子：
11
通讯作者：
Zhou, Shungui
中科院分区：
文献类型：
--
作者：
Liu, Xing;Zhuo, Shiyan;Zhou, Shungui
直接种间电子转移(DIEW)可能在表现出甲烷生成和厌氧甲烷氧化的微生物群落中占优势，并可以作为支持厌氧光合作用的电子源。以前对已确定的地杆菌共培养物的诱变研究表明，传导性菌毛和胞外细胞色素都是饮食所必需的。然而，由于这些研究中使用的菌毛突变策略影响了细胞外细胞色素谱，因此菌毛在饮食中的实际功能作用尚不确定。在这里，我们通过删除两种地质杆菌中的菌毛聚合马达PilB来抑制菌毛的功能。PilB突变抑制了菌毛的组装，但没有改变细胞外细胞色素的模式。我们报道了这两个无菌毛的地质杆菌物种可以形成聚集体，并随着饮食的共生生长。这些结果表明，金属还原地杆菌的GMET_2896细胞色素在饮食中起着关键作用，在共培养的地质杆菌中，导电菌毛不是促进饮食的必要条件，这表明细胞色素本身可以思考饮食，加深了对饮食的理解。
Direct interspecies electron transfer (DIET) may prevail in microbial communities that show methanogenesis and anaerobic methane oxidation and can be an electron source to support anaerobic photosynthesis. Previous mutagenic studies on cocultures of defined Geobacter species indicate that both conductive pili and extracellular cytochromes are essential for DIET. However, the actual functional role of the pili in DIET is uncertain, as the pilus mutation strategy used in these studies affected the extracellular cytochrome profile. Here we repressed the function of pili by deleting the pilus polymerization motor PilB in both Geobacter species. The PilB mutation inhibited the pilus assembly but did not alter the pattern of extracellular cytochromes. We report that the two pilus-free Geobacter species can form aggregates and grow syntrophically with DIET. The results demonstrate that the Gmet_2896 cytochrome of Geobacter metallireducens plays a key role in DIET and that conductive pili are not necessary to facilitate DIET in cocultures of Geobacter species, and they suggest cytochromes by themselves can meditate DIET, deepening the understanding of DIET.