Specificity and stability of the Acromyrmex-Pseudonocardia symbiosis

The stability of mutualistic interactions is likely to be affected by the genetic diversity of symbionts that compete for the same functional niche. Fungus-growing (attine) ants have multiple complex symbioses and thus provide ample opportunities to address questions of symbiont specificity and diversity. Among the partners are Actinobacteria of the genus Pseudonocardia that are maintained on the ant cuticle to produce antibiotics, primarily against a fungal parasite of the mutualistic gardens. The symbiosis has been assumed to be a hallmark of evolutionary stability, but this notion has been challenged by culturing and sequencing data indicating an unpredictably high diversity. We used 454 pyrosequencing of 16S rRNA to estimate the diversity of the cuticular bacterial community of the leaf-cutting ant Acromyrmex echinatior and other fungus-growing ants from Gamboa, Panama. Both field and laboratory samples of the same colonies were collected, the latter after colonies had been kept und...

互利共生相互作用的稳定性可能受到竞争同一功能生态位的共生体遗传多样性的影响。真菌种植蚁（attine ants）拥有多重复杂共生关系，因此为研究共生体特异性与多样性问题提供了充足机会。其共生伙伴包括伪诺卡氏菌属（Pseudonocardia）的放线菌（Actinobacteria），这些菌定植于蚂蚁表皮，能产生抗生素，主要用于抑制共生菌圃的真菌寄生虫。该共生关系曾被视为进化稳定性的标志，但这一观点已受到培养和测序数据的挑战——这些数据显示出超乎预期的高多样性。我们采用16S核糖体RNA（16S rRNA）的454焦磷酸测序（454 pyrosequencing）技术，对来自巴拿马甘博亚的刺切叶蚁（Acromyrmex echinatior）及其他真菌种植蚁的表皮细菌群落多样性进行了评估。其中，后者为实验室饲养的蚁群，饲养条件为未...