The rhizosphere microbiome plays a key role in plant nutrient provision. However, the impacts of the vertically transmitted seed microbiome on the assembly of the rhizosphere microbiome and consequently on the functional traits remain unclear. Here, to assess the role of seed-borne beneficial microbes on the assembly of rhizosphere microbiome, we conducted a guest-soil cultivation study using two maize cultivars and their corresponding native soils with different available nutrient contents. The assembly of the rhizosphere bacterial and fungal communities was assessed by amplicon DNA sequencing. Our results demonstrated that the soil microbiome dominates the assembly of the rhizosphere microbiome. A seed-borne beneficial bacterium, Burkholderia gladioli, was able to colonize the rhizosphere in great relative abundance, which significantly altered the assembly of the rhizosphere microbiome. Genome analysis demonstrated that this seed-borne beneficial bacterial species may contain extracellular phosphatase-encoding genes, and gene quantification confirmed their existence, suggesting the possible compensation of phosphate solubilizing function. This functional compensation, which is probably a response to the low concentration of soil available phosphorus, may consequently promote phosphorus acquisition of the host plant. Overall, this study provides new insights into our understanding of the assembly of the rhizosphere microbiome, suggesting that the seed microbiome serves as a functional compensation reservoir to enhance the fitness of progeny plants and highlighting the necessity to consider the seed microbiome during plant breeding.

根际微生物组在植物营养提供中起关键作用。但是，垂直传播的种子微生物组对根际微生物组的组装以及因此对功能性状的影响尚不清楚。在这里，为了评估种子传播的有益微生物在根际微生物组组装中的作用，我们使用两个玉米品种及其相应的具有不同有效养分含量的原生土壤进行了客体土壤培养研究。通过扩增子DNA测序评估根际细菌和真菌群落的组装。我们的结果表明，土壤微生物组在根际微生物组中占主导地位。种子传播的有益细菌，伯克霍尔德氏菌，能够在相对丰富的殖民地根际，这大大改变了根际微生物组的组装。基因组分析表明，这种种子传播的有益细菌可能含有细胞外磷酸酶编码基因，基因定量证实了它们的存在，表明可能对磷酸盐增溶功能进行了补偿。这种功能性补偿可能是对土壤有效磷浓度低的一种响应，因此可能促进宿主植物对磷的吸收。总体而言，这项研究为我们对根际微生物组组装的理解提供了新的见解，