College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China.
College of Animal Science and Technology, Qingdao Agriculture University, Qingdao, Shandong, 266109, China.
Sci Rep. 2017 Jun 15;7(1):3608. doi: 10.1038/s41598-017-03778-7.
Switchgrass (Panicum virgatum L.) is a cellulosic biofuel feedstock and their effects on bacterial communities in deep soils remain poorly understood. To reveal the responses of bacterial communities to long-term switchgrass cultivation through the soil profile, we examined the shift of soil microbial communities with depth profiles of 0-60 cm in five-year switchgrass cultivation and fallow plots. The Illumina sequencing of the 16S rRNA gene showed that switchgrass cultivation significantly increased microbial OTU richness, rather than microbial Shannon diversity; however, there was no significant difference in the structure of microbial communities between switchgrass cultivation and fallow soils. Both switchgrass cultivation and fallow soils exhibited significant negative vertical spatial decay of microbial similarity, indicating that more vertical depth distant soils had more dissimilar communities. Specifically, switchgrass cultivation soils showed more beta-diversity variations across soil depth profile. Through network analysis, more connections and closer relationships of microbial taxa were observed in soils under switchgrass cultivation, suggesting that microbial co-occurrence patterns were substantially influenced by switchgrass cultivation. Overall, our study suggested that five-year switchgrass cultivation could generated more beta-diversity variations across soil depth and more complex inter-relationships of microbial taxa, although did not significantly shape the structure of soil microbial community.
柳枝稷（Panicum virgatum L.）是一种纤维素生物燃料原料，但其对深层土壤细菌群落的影响仍知之甚少。为了揭示长期柳枝稷种植对土壤细菌群落的响应，我们通过对五年柳枝稷种植和休耕地块的 0-60cm 土壤深度剖面，研究了土壤微生物群落的变化。16S rRNA 基因的 Illumina 测序结果表明，柳枝稷种植显著增加了微生物 OTU 丰富度，而不是微生物 Shannon 多样性；然而，柳枝稷种植和休耕土壤之间的微生物群落结构没有显著差异。柳枝稷种植和休耕土壤的微生物相似性均呈现显著的负垂直空间衰减，表明距离垂直深度越远的土壤具有更多不同的群落。具体来说，柳枝稷种植土壤在整个土壤深度剖面表现出更多的 beta 多样性变化。通过网络分析，我们观察到在柳枝稷种植土壤中，微生物类群之间存在更多的连接和更密切的关系，这表明微生物共存模式受到柳枝稷种植的实质性影响。总的来说，我们的研究表明，尽管五年的柳枝稷种植没有显著改变土壤微生物群落的结构，但它可以在整个土壤深度上产生更多的 beta 多样性变化，并形成更复杂的微生物类群之间的相互关系。
