Rhizosphere microbes are critical for plant growth and vitality, but the structure of the root-associated microbial community varies due to site-specific soil factors and plant traits. Here, we investigated how soil type and plant species affect the rhizosphere microbial community. Soil types were collected from a rice field or a secondary forest. Each soil was planted with either pathogen-inoculated or un-inoculated seeds of Fusarium wilt-susceptible (watermelon and cucumber) or Fusarium wilt-resistant (celery) crops. Analysis of the rhizosphere microbial communities revealed differences in the same crop that was planted on different soil types, as well as between crops grown on the same soil type. Thus, there are soil-specific and plant species-specific factors that determine the rhizosphere microbial community structure. However, we found that the plant species effect on microbial community structure (explaining 18.1% of the variance in bacterial species and 13.3% of variance in fungal species) was less than the soil type effect (variance explained: 47.1% for bacteria, 29.2% for fungi). Notably, soil NH₄⁺-N concentration was the most influential soil-specific factor affecting rhizosphere microbial community composition. The rhizosphere of each plant species harbored core and unique microbes that were different in their relative abundance and composition. The pathogen-inoculated plants had a similar rhizosphere microbial community as those that were not inoculated with Fusarium wilt-causing fungus, although there was an increase in the relative abundances of microbial genera associated with biological disease control and maintenance of plant health. We conclude that the rhizosphere microbial community structure is determined more by soil type than the plant species cultivated in that soil.

根际微生物对植物的生长和生命力至关重要，但是根系相关微生物群落的结构因特定的土壤因子和植物性状而异。在这里，我们调查了土壤类型和植物物种如何影响根际微生物群落。土壤类型是从稻田或次生林中收集的。每种土壤都种植了病原体接种或未接种的枯萎病（西瓜和黄瓜）或枯萎病抗性（芹菜）作物种子。对根际微生物群落的分析表明，种植在不同土壤类型上的同一作物以及种植在同一土壤类型上的作物之间存在差异。因此，存在决定土壤根际微生物群落结构的土壤特异性和植物物种特异性因素。然而，我们发现植物物种对微生物群落结构的影响（解释了细菌种类变异的18.1％和真菌种类变异的13.3％）小于土壤类型的影响（变异解释为：细菌47.1％，真菌29.2％ ）。值得注意的是，土壤NH₄ ⁺ -N浓度是影响根际微生物群落组成的最具影响力的土壤特异性因子。每个植物物种的根际都具有核心和独特的微生物，它们的相对丰度和组成不同。接种病原菌的植物与未接种枯萎病枯萎真菌的植物具有相似的根际微生物群落，尽管与控制生物病害和维持植物健康有关的微生物属的相对丰度有所增加。我们得出的结论是，根际微生物群落结构更多地取决于土壤类型，而不是该土壤中种植的植物物种。