Crop establishment practices are a driver of the plant microbiota in winter oilseed rape (Brassica napus). Winter oilseed rape microbiome_1

Gaining a greater understanding of the plant microbiota and its interactions with its host plant heralds a new era of scientific discovery in agriculture. Different agricultural management practices influence soil microbial populations by changing a soil’s physical, chemical and biological properties. However, the impact of these practices on the microbiota associated with economically important crops such as oilseed rape, are still understudied. In this work we investigated the impact of two contrasting crop establishment practices, conventional (plow based) and conservation (strip–tillage) systems, on the microbiota inhabiting different plant microhabitats, namely rhizosphere, root and shoot, of winter oilseed rape under Irish agronomic conditions. Illumina 16S rRNA gene sequence profiling showed that the plant associated microhabitats (root and shoot), are dominated by members of the bacterial phyla Proteobacteria, Actinobacteria and Bacteroidetes. The root and shoot associated bacterial communities displayed markedly distinct profiles as a result of tillage practices. We observed a very limited ‘rhizosphere effect’ in the root zone of WOSR, i.e., there was little or no increase in bacterial community richness and abundance in the WOSR rhizosphere compared to the bulk soil. The two tillage systems investigated did not appear to lead to any major long term differences on the bulk soil or rhizosphere bacterial communities. Our data suggests that the WOSR root and shoot microbiota can be impacted by management practices and is an important mechanism that could allow us to understand how plants respond to different management practices and environments.

深入解析植物微生物群（plant microbiota）及其与宿主植物（host plant）的互作关系，正引领农业科学研究迈入全新的发现纪元。不同农业管理措施可通过改变土壤的物理、化学与生物学特性，对土壤微生物种群产生调控作用。然而，此类措施对油菜（oilseed rape）等经济作物相关微生物群的影响，仍有待系统探究。本研究以爱尔兰农业种植环境下的冬油菜（winter oilseed rape, WOSR）为研究对象，探究了两种截然不同的作物种植模式——常规（翻耕）体系（conventional plow-based）与保护性（条带耕作）体系（conservation strip-tillage）——对其不同植物微生境（plant microhabitats），即根际（rhizosphere）、根系与地上部内定植微生物群的影响。Illumina平台16S rRNA基因测序分析（Illumina 16S rRNA gene sequence profiling）结果显示，植物相关微生境（根系与地上部）的优势细菌类群隶属于变形菌门（Proteobacteria）、放线菌门（Actinobacteria）与拟杆菌门（Bacteroidetes）。耕作模式的差异使得根系与地上部的细菌群落呈现出显著分化的结构。我们在冬油菜根区观察到极弱的根际效应（rhizosphere effect）：相较于非根际土壤（bulk soil），冬油菜根际的细菌群落丰富度与丰度几乎未出现显著提升。本研究所采用的两种耕作体系，似乎并未对非根际土壤或根际的细菌群落造成显著的长期差异。本研究结果表明，冬油菜根系与地上部的微生物群可受种植管理措施调控，这一发现可为解析植物对不同管理措施与环境的响应提供重要理论依据。