Data from: The hindgut-lumen prokaryotic microbiota of the lignocellulose-degrading termite Reticulitermes flavipes and its responses to dietary lignocellulose composition

Reticulitermes flavipes (Isoptera: Rhinotermitidae) is a highly eusocial insect that thrives on recalcitrant lignocellulosic diets through nutritional symbioses with gut-dwelling prokaryotes and eukaryotes. In the R. flavipes hindgut, there are up to 12 eukaryotic protozoan symbionts; the number of prokaryotic symbionts has been estimated in the hundreds. Despite its biological relevance, this diverse community, to date, has been investigated only by culture- and cloning-dependent methods. Moreover, it is unclear how termite gut microbiomes respond to diet changes and what roles they play in lignocellulose digestion. This study utilized high-throughput 454 pyrosequencing of 16S V5-V6 amplicons to sample the hindgut lumen prokaryotic microbiota of R. flavipes and to examine compositional changes in response to lignin-rich and lignin-poor cellulose diets after a 7-day feeding period. Of the ~475 000 high-quality reads that were obtained, 99.9% were annotated as bacteria and 0.11% as archaea. Major bacterial phyla included Spirochaetes (24.9%), Elusimicrobia (19.8%), Firmicutes (17.8%), Bacteroidetes (14.1%), Proteobacteria (11.4%), Fibrobacteres (5.8%), Verrucomicrobia (2.0%), Actinobacteria (1.4%) and Tenericutes (1.3%). The R. flavipes hindgut lumen prokaryotic microbiota was found to contain over 4761 species-level phylotypes. However, diet-dependent shifts were not statistically significant or uniform across colonies, suggesting significant environmental and/or host genetic impacts on colony-level microbiome composition. These results provide insights into termite gut microbiome diversity and suggest that (i) the prokaryotic gut microbiota is much more complex than previously estimated, and (ii) environment, founding reproductive pair effects and/or host genetics influence microbiome composition.

黄胸散白蚁（Reticulitermes flavipes，等翅目：鼻白蚁科）是一类高度社会化的昆虫，通过与定居于肠道的原核生物及真核生物建立营养共生关系，得以利用难降解的木质纤维素膳食生存繁衍。在黄胸散白蚁的后肠中，已发现多达12种真核原生动物共生体；而原核共生体的数量据估计可达数百种。尽管该共生群落具有重要的生物学意义，但迄今为止相关研究仅依赖于培养法与克隆技术开展。此外，目前尚不清楚白蚁肠道微生物组如何响应膳食变化，以及它们在木质纤维素消化过程中发挥何种作用。本研究针对16S rRNA基因V5-V6高变区扩增子开展高通量454焦磷酸测序，对黄胸散白蚁后肠肠腔的原核微生物组进行采样，并探究其在为期7天的饲喂期后，对富木质素与贫木质素纤维素膳食的组成响应变化。在获取的约475,000条高质量测序读段中，99.9%被注释为细菌，0.11%被注释为古菌。主要的细菌菌门包括螺旋体门（24.9%）、迷踪菌门（19.8%）、厚壁菌门（17.8%）、拟杆菌门（14.1%）、变形菌门（11.4%）、纤维杆菌门（5.8%）、疣微菌门（2.0%）、放线菌门（1.4%）以及软壁菌门（1.3%）。研究发现黄胸散白蚁后肠肠腔原核微生物组包含超过4761个物种水平的系统发育类群。然而，不同蚁群间膳食诱导的群落组成变化并未达到统计学显著性，且变化模式并不统一，这表明环境因素、宿主遗传因素或二者共同对蚁群水平的微生物组组成具有显著影响。本研究结果为白蚁肠道微生物组多样性研究提供了新视角，并提出两点结论：其一，肠道原核微生物组的复杂程度远高于此前的预估；其二，环境因素、建群繁殖对效应以及宿主遗传因素共同影响微生物组的组成。