Data from: Home-made cost effective preservation buffer is a better alternative to commercial preservation methods for microbiome research

The investigation of wildlife gastrointestinal microbiomes by next-generation sequencing approaches is a growing field in microbial ecology and conservation. Such studies often face difficulties in sample preservation if neither freezing facilities nor liquid nitrogen (LQN) are readily available. Thus, in order to prevent microbial community changes because of bacterial growth after sampling, preservation buffers need to be applied to samples. However, the amount of microbial community variation attributable to the different preservation treatments and potentially affecting biological interpretation is hardly known. Here, we sampled feces of 11 sheep (Ovis aries sp.) by using swabs and analyzed the effect of air-drying, an inexpensive self-made nucleic acid preservation buffer (NAP), DNA/RNA Shield™, and RNAlater®, each together with freezing (for 10 days) or storing at room temperature (for 10 days) prior to 16S rRNA gene high-throughput sequencing to determine bacterial communities. Results revealed that the proportions of operational taxonomic units (OTUs) belonging to a bacterial phylum were affected by the preservation treatments, and that alpha diversities (observed OTUs, Shannon index, and phylogenetic diversity (PD)) were lower in all preservation treatments than in samples taken by forensic swabs and immediately frozen which is considered as the favored preservation treatment in the absence of any logistic constraints. Overall, NAP had better preservation qualities than RNAlater® and DNA/RNA Shield™ making this self-made buffer a valuable solution in wildlife microbiome studies.

利用高通量测序（next-generation sequencing）技术开展野生动物胃肠道微生物组研究，是微生物生态学与保护生物学领域的新兴研究方向。此类研究常面临样本保存难题：若无法便捷获取冷冻设备与液氮（liquid nitrogen，LQN），往往在样本保存环节遭遇诸多困难。因此，为避免采样后细菌增殖引发微生物群落结构改变，需对样本使用保存缓冲液进行处理。然而，不同保存处理方式所导致的微生物群落差异幅度，及其可能对生物学解读造成的影响，目前仍鲜为人知。
本研究以拭子采集11只绵羊（Ovis aries sp.）的粪便样本，分析自然风干、自制低成本核酸保存缓冲液（NAP）、DNA/RNA Shield™以及RNAlater®四种保存方式的效果；每种保存方式均设置两组处理条件：冷冻保存10天，或室温放置10天，后续通过16S rRNA基因高通量测序解析细菌群落组成。
研究结果显示，隶属于某一细菌门的操作分类单元（operational taxonomic units，OTUs）的相对丰度会受到保存处理方式的影响；且所有保存处理组的α多样性（观测OTU数、香农指数与系统发育多样性（PD））均低于经无菌拭子采集并立即冷冻的样本——该处理方式被视为无后勤约束条件下的首选保存方案。
综合来看，自制核酸保存缓冲液（NAP）的保存效果优于RNAlater®与DNA/RNA Shield™，可为野生动物微生物组研究提供一种极具实用价值的解决方案。