Climate change may fundamentally affect the microorganisms in the rhizosphere that drive soil C and nutrient cycles. This study aimed to clarify the response of rhizobacterial community to warming and elevated CO₂ (eCO₂) in typical maize (Zea mays L.)-growing soils. Under climate change, the shift of rhizobacterial community composition was assumed to be different among soils, which would be associated with the C sequestration and stability in soils. Using open-top chambers to mimic climate warming and eCO₂, we examined the taxonomic composition of bacterial communities in the rhizosphere of maize grown in four farming soils (Acrisol, Fluvisol, Kastanozem, and Phaeozem). Warming decreased the richness of the rhizobacterial community by 3.8% across the soils, but eCO₂ did not significantly alter community richness. The shift in bacterial community composition was greater under warming than under eCO₂, and the shift was different among soils. The abundance of Streptomyces and Gaiella significantly increased in Phaeozem and Acrisol in response to warming but not in Fluvisol or Kastanozem. Sphingomonas was suppressed in Phaeozem under warming, whereas Sphingomonas, Shinella, and Rhodospirillaceae_norank were enriched in the other three soils. Soil chemical characteristics including nitrate, Olsen P, available K, and soil organic C (SOC) were significantly associated with a number of dominant operational taxonomic units. These results indicate that the effect of warming on bacterial community composition in the rhizosphere of maize may be stronger than the effect of eCO₂. Climate change led to various changes in the rhizobacterial community composition among soils that might be associated with the quality of SOC and nutrient status in different soils.

中文翻译：

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变暖而不是二氧化碳升高改变了四种玉米种植土壤中的根际细菌群落组成

气候变化可能从根本上影响驱动土壤碳和养分循环的根际微生物。本研究旨在阐明根际细菌群落对典型玉米 ( Zea mays L.) 生长土壤中变暖和 CO ₂ (eCO ₂ )升高的响应。在气候变化下，假定土壤间根际细菌群落组成的变化不同，这与土壤中的碳封存和稳定性有关。使用开顶室来模拟气候变暖和 eCO ₂，我们检查了在四种耕作土壤（Acrisol、Fluvisol、Kastanozem 和 Phaeozem）中生长的玉米根际细菌群落的分类组成。变暖使土壤中根际细菌群落的丰富度降低了 3.8%，但 eCO ₂并未显着改变群落丰富度。细菌群落组成的变化在变暖条件下比在eCO ₂条件下更大，并且不同土壤的变化不同。Phaeozem 和 Acrisol 中Streptomyces和Gaiella的丰度随着变暖而显着增加，但在 Flurisol 或 Kastanozem 中没有。变暖条件下 Phaeozem 中的鞘氨醇单胞菌被抑制，而鞘氨醇单胞菌、Shinella, 和Rhodospirillaceae_norank在其他三种土壤中富集。包括硝酸盐、Olsen P、有效钾和土壤有机碳 (SOC) 在内的土壤化学特征与许多主要的操作分类单元显着相关。这些结果表明变暖对玉米根际细菌群落组成的影响可能强于eCO ₂的影响。气候变化导致土壤中根际细菌群落组成的各种变化，这可能与不同土壤的 SOC 质量和养分状况有关。