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.利用下一代测序（next-generation sequencing）技术探究野生动物胃肠道微生物组，是微生物生态学与保护生物学领域中日益受到关注的研究方向。此类研究常面临样本保存难题：若无法便捷获取冷冻设备或液氮（Liquid Nitrogen, LQN），则难以抑制采样后细菌增殖所引发的微生物群落结构变化，因此需借助保存缓冲液处理样本。然而，不同保存处理所导致的微生物群落变异程度，及其可能对生物学解读造成的影响，目前仍鲜为人知。本研究以棉拭子采集11只绵羊（Ovis aries）的粪便样本，设置风干、自制核酸保存缓冲液（nucleic acid preservation buffer, NAP）、DNA/RNA Shield™以及RNAlater®四种保存方案，每种方案分别配合10天冷冻保存或10天室温保存，随后通过16S rRNA基因高通量测序分析细菌群落组成。研究结果显示，隶属于特定细菌门的操作分类单元（Operational Taxonomic Unit, OTU）的相对丰度会受到保存处理的影响；且相较于经法医棉拭子采集后立即冷冻（无任何实验条件限制时的最优保存方案）的样本，所有其他保存处理组的α多样性（观测OTU数量、香农指数以及系统发育多样性（phylogenetic diversity, PD））均更低。整体而言，自制的NAP缓冲液的保存效果优于RNAlater®与DNA/RNA Shield™，可作为野生动物微生物组研究中极具应用价值的低成本解决方案。