附生于其它细胞体内的胞内共生关系 (Endosymbiotic relationships)，通常被认为是一种寄生性的行为，不过最新的一项研究却证实，一种真菌细胞里所发现的共生细菌，却是真菌细胞进行生理活动所必须。
据了解这个由德国自然产物与感染生物研究院 (Natural Product Research and Infection Biology) Leibniz 研究所(Leibniz Institute) 科学家，Laila Partida和 Christian Hertweck所共同参与的研究计划，发现属于真菌 Rhizopus microsporus 的细胞里，存在着一种称为Burkholderia 的细菌，研究人员深入的分析，发现这两个共生在一起的微生物，居然可以共同的参与代谢，分解植物植株幼苗，造成所谓幼苗枯萎病(seedling blight) 的发生，研究人员还发现，Burkholderia 细菌所分泌的毒素rhizoxin，在真菌引发幼苗枯萎病的关键过程中，扮演着不可缺少的角色。
此外研究人员如果施用抗生素，来截杀真菌里的细菌，结果虽然可以有效的防治细菌的存在，但原为宿主角的真菌，也失去了生殖复制的功能。
这些现象违反了长久以来科学家的观点，认为寄生在他种生物细胞内的细菌，多为对宿主引发不良反应的作用，从没想过寄生的细菌，也是参与宿主细胞代谢重要的一环，成为互利共生 (mutualism)最好的一个例子。
(资料来源 : biocompare)
原始出处: http://news.biocompare.com/newsstory.asp?id=177464
部分英文原文：
Current Biology
10.1016/j.cub.2007.03.039
Report
Endosymbiont-Dependent Host Reproduction Maintains Bacterial-Fungal Mutualism
Laila P. Partida-Martinez1, Shamci Monajembashi2, Karl-Otto Greulich2 and Christian Hertweck1, 3, ,
1Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), 07745 Jena, Germany
2Leibniz Institute for Age Research, Fritz Lipmann Institute (FLI), 07745 Jena, Germany
3Friedrich-Schiller-University, 07745 Jena, Germany
Received 8 February 2007; revised 1 March 2007; accepted 7 March 2007. Published online: April 5, 2007. Available online 5 April 2007.
Summary
[NextPage]
Bacterial endosymbionts play essential roles for many organisms, and thus specialized mechanisms have evolved during evolution that guarantee the persistence of the symbiosis during or after host reproduction 1 and 2. The rice seedling blight fungus Rhizopus microsporus represents a unique example of a mutualistic life form in which a fungus harbors endobacteria (Burkholderia sp.) for the production of a phytotoxin [3]. Here we report the unexpected observation that in the absence of endosymbionts, the host is not capable of vegetative reproduction. Formation of sporangia and spores is restored only upon reintroduction of endobacteria. To monitor this process, we succeeded in GFP labeling cultured endosymbionts. We also established a laserbeam transformation technique for the first controlled introduction of bacteria into fungi to observe their migration to the tips of the aseptate hyphae. The persistence of this fungal-bacterial mutualism through symbiont-dependent sporulation is intriguing from an evolutionary point of view and implies that the symbiont produces factors that are essential for the fungal life cycle. Reproduction of the host has become totally dependent on endofungal bacteria, which in return provide a highly potent toxin for defending the habitat and accessing nutrients from decaying plants. This scenario clearly highlights the significance for a controlled maintenance of this fungal-bacterial symbiotic relationship.
Author Keywords: EVO_ECOL
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