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.

农户在作物选育与推广过程中繁育出大量植物品系，但学界此前却忽略了该作物多样化进程对植物-微生物互作（plant-microbe interaction）的影响。本研究提出假说：作物的演化历史会塑造其后续品系与根际（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、隶属于5个主要玉米遗传类群的近交系（inbred line）为材料，通过比较各品系的根际细菌群落（rhizobacterial community）组成，评估了玉米多样化作为幼苗根系筛选土壤细菌影响因素的重要性。本研究采用靶向覆盖19个细菌门（bacterial phylum）的16S rRNA分类学微阵列（16S rRNA taxonomic microarray），对21日龄幼苗的根际细菌群落组成进行了分析。结果显示，近交系的根际细菌群落组成与其所属的玉米遗传类群密切相关。群落组成的差异主要源于特定β-变形菌纲（Betaproteobacteria）尤其是伯克霍尔德菌属（Burkholderia）的丰度优势，该结论经定量聚合酶链式反应（quantitative PCR）与克隆测序（cloning/sequencing）验证。但根系细菌定殖（bacterial root colonization）的这类差异，与玉米遗传类群或单个品系之间的植物微卫星标记（microsatellite）遗传距离并无关联。因此，在作物多样化进程中形成的玉米遗传结构（最终分化为5个主要类群），而非玉米多样化本身的程度（通过玉米遗传距离测定），才是塑造幼苗根际细菌群落组成的关键因素。