Data_Sheet_2_Exploring the Prokaryotic Community Associated With the Rumen Ciliate Protozoa Population.PDF

Ciliate protozoa are an integral part of the rumen microbiome and were found to exert a large effect on the rumen ecosystem itself as well as their host animal physiology. Part of these effects have been attributed to their ability to harbor a diverse ecto- and endo-symbiotic community of prokaryotic cells. Studies on the relationship between the protozoa population and their associated prokaryotic community in the rumen mainly focused on the methanogens, revealing that protozoa play a major role in enhancing methanogenesis potential. In contrast, little is known about the composition and function of the bacteria associated with rumen protozoa and the extent of this association. In this study, we characterize the prokaryotic communities associated with different protozoa populations and compare their structure to the free-living prokaryotic population residing in the cow rumen. We show that the overall protozoa associated prokaryotic community structure differs significantly compared to the free-living community in terms of richness and composition. The methanogens proportion was significantly higher in all protozoa populations compared to the free-living fraction, while the Lachnospiraceae was the most prevalent bacterial family in the protozoa associated bacterial communities. Several taxa not detected or detected in extremely low abundance in the free-living community were enriched in the protozoa associated bacterial community. These include members of the Endomicrobia class, previously identified as protozoa symbionts in the termite gut. Our results show that rumen protozoa harbor prokaryotic communities that are compositionally different from their surroundings, which may be the result of specific tropism between the prokaryotic community and protozoa.

纤毛虫类原生动物是瘤胃微生物群的重要组成部分，研究发现它们对瘤胃生态系统本身及其宿主动物的生理机能具有重大影响。其中部分影响归因于它们能够容纳多样的外共生和内共生原核细胞群落。关于瘤胃原生动物及其相关原核群落之间关系的研究主要集中于产甲烷菌，揭示原生动物在增强产甲烷潜力方面发挥着关键作用。相比之下，关于与瘤胃原生动物相关联的细菌组成和功能，以及这种关联的程度，了解甚少。在本研究中，我们描述了与不同原生动物种群相关联的原核群落，并将其结构与生活在牛瘤胃中的自由生活原核种群进行比较。我们发现，与自由生活群落相比，在丰富度和组成方面，与原生动物相关联的原核群落结构存在显著差异。在所有原生动物种群中，产甲烷菌的比例均显著高于自由生活部分，而Lachnospiraceae族在原生动物相关细菌群落中最为普遍。在自由生活群落中未检测到或含量极低的几个类群，在原生动物相关细菌群落中得到了富集。这些包括Endomicrobia类群的成员，之前在白蚁肠道中被识别为原生动物的共生体。我们的结果表明，瘤胃原生动物携带与周围环境组成不同的原核群落，这可能是原核群落与原生动物之间特异性趋同的结果。