Generalized antifungal activity and 454-screening of Pseudonocardia and Amycolatopsis bacteria in nests of fungus-growing ants
Generalized antifungal activity and 454-screening of Pseudonocardia and Amycolatopsis bacteria in nests of fungus-growing ants
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DOI：
10.1073/pnas.0904827106
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发表时间：
2009-10-20
影响因子：
11.1
通讯作者：
Mueller, Ulrich G.
中科院分区：
文献类型：
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作者：
Sen, Ruchira;Ishak, Heather D.;Mueller, Ulrich G.
在许多宿主-微生物互惠关系中，宿主利用微生物共生体提供的有益代谢物。真菌生长（attine）蚂蚁被认为与假诺卡氏菌形成这种互惠共生关系，以获得抗生素，专门抑制共同进化的病原体Escovopsis，它感染蚂蚁的真菌花园并减少生长。在这里，我们测试这个假诺卡氏菌Escovopsis协同进化模型的4个关键假设。文化依赖和文化独立（标签编码的454焦磷酸测序）的调查显示，几个假诺卡氏菌物种，偶尔Amycolatopsis（一个近亲的假诺卡氏菌）共同发生在工人从一个单一的巢，矛盾的假设，一个单一的假诺卡氏菌菌株每巢。假诺卡氏菌可以发生在男性身上，这表明假诺卡氏菌也可以在交配过程中水平传播。假诺卡氏菌和拟无枝酸菌的分泌物杀死或强烈抑制蚂蚁培养的真菌，矛盾的生长促进作用的假诺卡氏菌的品种上以前的发现。因此，如果Attine蚂蚁在生长活跃的花园中使用假蝇科的分泌物，它们可能会伤害自己的品种。假诺卡氏菌和Amycolatopsis菌株也表现出非特异性的抗真菌活性，对腐食性，内生，昆虫病原，和花园病原真菌，相反，对Escovopsis单独的具体pesticsis的原始报告。我们的结论是，attine相关的necocardiaceous细菌不表现出衍生的抗生素特性，以具体抑制Escovopsis。我们评估假设的非适应性和适应性功能的attine皮肤细菌，并开发一个替代的概念框架，以取代流行的假诺卡氏菌Escovopsis的共同进化模型。如果与假诺卡氏菌的联系是适应于蚂蚁的，那么这种微生物的替代作用可能包括保护蚂蚁或清洁巢穴。
In many host-microbe mutualisms, hosts use beneficial metabolites supplied by microbial symbionts. Fungus-growing (attine) ants are thought to form such a mutualism with Pseudonocardia bacteria to derive antibiotics that specifically suppress the coevolving pathogen Escovopsis, which infects the ants' fungal gardens and reduces growth. Here we test 4 key assumptions of this Pseudonocardia-Escovopsis coevolution model. Culture-dependent and culture-independent (tag-encoded 454-pyrosequencing) surveys reveal that several Pseudonocardia species and occasionally Amycolatopsis ( a close relative of Pseudonocardia) co-occur on workers from a single nest, contradicting the assumption of a single pseudonocardiaceous strain per nest. Pseudonocardia can occur on males, suggesting that Pseudonocardia could also be horizontally transmitted during mating. Pseudonocardia and Amycolatopsis secretions kill or strongly suppress ant-cultivated fungi, contradicting the previous finding of a growth-enhancing effect of Pseudonocardia on the cultivars. Attine ants therefore may harm their own cultivar if they apply pseudonocardiaceous secretions to actively growing gardens. Pseudonocardia and Amycolatopsis isolates also show nonspecific antifungal activities against saprotrophic, endophytic, entomopathogenic, and garden-pathogenic fungi, contrary to the original report of specific antibiosis against Escovopsis alone. We conclude that attine-associated pseudonocardiaceous bacteria do not exhibit derived antibiotic properties to specifically suppress Escovopsis. We evaluate hypotheses on non-adaptive and adaptive functions of attine integumental bacteria, and develop an alternate conceptual framework to replace the prevailing Pseudonocardia-Escovopsis coevolution model. If association with Pseudonocardia is adaptive to attine ants, alternate roles of such microbes could include the protection of ants or sanitation of the nest.