Mahoney Aaron K, Yin Chuntao, Hulbert Scot H
Department of Plant Pathology, Washington State University, PullmanWA, USA; Molecular Plant Sciences, Washington State University, PullmanWA, USA.
Department of Plant Pathology, Washington State University, Pullman WA, USA.
Front Plant Sci. 2017 Feb 13;8:132. doi: 10.3389/fpls.2017.00132. eCollection 2017.
Minimal tillage management of extensive crops like wheat can provide significant environmental services but can also lead to adverse interactions between soil borne microbes and the host. Little is known about the ability of the wheat cultivar to alter the microbial community from a long-term recruitment standpoint, and whether this recruitment is consistent across field sites. To address this, nine winter wheat cultivars were grown for two consecutive seasons on the same plots on two different farm sites and assessed for their ability to alter the rhizosphere bacterial communities in a minimal tillage system. Using deep amplicon sequencing of the V1-V3 region of the 16S rDNA, a total of 26,604 operational taxonomic units (OTUs) were found across these two sites. A core bacteriome consisting of 962 OTUs were found to exist in 95% of the wheat rhizosphere samples. Differences in the relative abundances for these wheat cultivars were observed. Of these differences, 24 of the OTUs were found to be significantly different by wheat cultivar and these differences occurred at both locations. Several of the cultivar-associated OTUs were found to correspond with strains that may provide beneficial services to the host plant. Network correlations demonstrated significant co-occurrences for different taxa and their respective OTUs, and in some cases, these interactions were determined by the wheat cultivar. Microbial abundances did not play a role in the number of correlations, and the majority of the co-occurrences were shown to be positively associated. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to determine potential functions associated with OTUs by association with rhizosphere members which have sequenced metagenomics data. Potentially beneficial pathways for nitrogen, sulfur, phosphorus, and malate metabolism, as well as antimicrobial compounds, were inferred from this analysis. Differences in these pathways and their associated functions were found to differ by wheat cultivar. In conclusion, our study suggests wheat cultivars are involved in shaping the rhizosphere by differentially altering the bacterial OTUs consistently across different sites, and these altered bacterial communities may provide beneficial services to the host.
对小麦等粗放型作物进行少耕管理可提供重要的环境服务，但也可能导致土壤微生物与宿主之间产生不利的相互作用。从长期招募的角度来看，关于小麦品种改变微生物群落的能力，以及这种招募在不同田间地点是否一致，我们所知甚少。为了解决这个问题，九个冬小麦品种在两个不同农场的同一地块上连续种植了两个季节，并评估了它们在少耕系统中改变根际细菌群落的能力。通过对16S rDNA的V1-V3区域进行深度扩增子测序，在这两个地点共发现了26,604个可操作分类单元（OTU）。发现在95%的小麦根际样本中存在一个由962个OTU组成的核心细菌群落。观察到这些小麦品种在相对丰度上存在差异。在这些差异中，发现有24个OTU在不同小麦品种间存在显著差异，且在两个地点均如此。发现几个与品种相关的OTU与可能为宿主植物提供有益服务的菌株相对应。网络相关性表明不同分类群及其各自的OTU之间存在显著的共现关系，在某些情况下，这些相互作用由小麦品种决定。微生物丰度在相关性数量上不起作用，且大多数共现关系显示为正相关。通过重建未观察状态对群落进行系统发育研究，以通过与具有宏基因组测序数据的根际成员关联来确定与OTU相关的潜在功能。从该分析中推断出了氮、硫、磷和苹果酸代谢以及抗菌化合物的潜在有益途径。发现这些途径及其相关功能的差异因小麦品种而异。总之，我们的研究表明，小麦品种通过在不同地点一致地差异改变细菌OTU来参与塑造根际，并且这些改变的细菌群落可能为宿主提供有益服务。
