Data from: Is diversification history of maize influencing selection of soil bacteria by roots?

A wide range of plant lines has been propagated by farmers during crop selection and dissemination, but consequences of this crop diversification on plant-microbe interactions have been neglected. Our hypothesis was that crop evolutionary history shaped the way the resulting lines interact with soil bacteria in their rhizospheres. Here, the significance of maize diversification as a factor influencing selection of soil bacteria by seedling roots was assessed by comparing rhizobacterial community composition of inbred lines representing the five main genetic groups of maize, cultivated in a same European soil. Rhizobacterial community composition of 21-day-old seedlings was analyzed using a 16S rRNA taxonomic microarray targeting 19 bacterial phyla. Rhizobacterial community composition of inbred lines depended on the maize genetic group. Differences were largely due to the prevalence of certain Betaproteobacteria and especially Burkholderia, as confirmed by quantitative PCR and cloning/sequencing. However, these differences in bacterial root colonization did not correlate with plant microsatellite genetic distances between maize genetic groups or individual lines. Therefore, the genetic structure of maize that arose during crop diversification (resulting in five main groups), but not the extent of maize diversification itself (as determined by maize genetic distances), was a significant factor shaping rhizobacterial community composition of seedlings.

在作物选育与推广过程中，农户已繁育出大量玉米品系，但该作物多样化进程对植物-微生物互作（plant-microbe interactions）产生的影响长期遭到忽视。我们提出的假说为：作物演化历史塑造了不同品系与其根际（rhizosphere）土壤细菌的互作模式。本研究以同一块欧洲农田土壤为栽培基质，选取代表5个主要玉米遗传类群的自交系（inbred lines）作为材料，评估玉米多样化作为幼苗根系筛选土壤细菌的影响因素的显著性。通过靶向19个细菌门的16S核糖体RNA（16S rRNA）分类学微阵列（taxonomic microarray），对21日龄幼苗的根际细菌群落组成进行分析。结果显示，玉米自交系的根际细菌群落组成取决于其所属的遗传类群，该差异主要由某些β-变形菌门（Betaproteobacteria，尤其是伯克霍尔德氏菌属Burkholderia）的相对丰度变化所驱动，该结论经定量PCR（quantitative PCR）与克隆测序（cloning/sequencing）验证。不过，根系细菌定殖的上述差异与玉米遗传类群间或各品系间的微卫星（microsatellite）遗传距离并无关联。综上，作物多样化进程中形成的玉米遗传结构（可划分为5个主要类群），而非玉米多样化程度本身（由玉米遗传距离表征），是塑造幼苗根际细菌群落组成的重要影响因素。