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.

在玉米的选育与推广过程中，农户已繁育出大量玉米品系，但该作物多样化进程对植物-微生物互作所产生的影响却长期被忽视。本研究提出假说：作物的演化历史塑造了后续品系与其根际（rhizosphere）土壤细菌的互作模式。本研究以种植于同一块欧洲农田土壤中的、涵盖玉米五大主要遗传类群的近交系为实验材料，通过比较其根际细菌群落组成，评估了玉米多样化作为影响幼苗根系筛选土壤细菌的因素的重要性。研究采用靶向19个细菌门的16S核糖体RNA（16S rRNA）分类微阵列，对21日龄幼苗的根际细菌群落组成进行了分析。结果表明，不同近交系的根际细菌群落组成与其所属的玉米遗传类群显著相关。该差异主要源于特定β-变形菌纲（Betaproteobacteria）类群的丰度变化，尤以伯克霍尔德菌属（Burkholderia）为甚，该结论经定量聚合酶链式反应（qPCR）与克隆测序验证。然而，根系细菌定殖的上述差异与玉米遗传类群或单个品系之间的微卫星遗传距离并无相关性。综上，在作物多样化进程中形成的玉米遗传结构（即五大遗传类群），而非玉米多样化的程度（通过遗传距离衡量），是影响幼苗根际细菌群落组成的关键因素。