Aims and background

The composition and function of rhizosphere microbiomes depend on interactions between plant roots and soil nutrient conditions. However, the influence of genetic variation of plant species on root-associated microorganisms and their nutrient cycling activities remains poorly understood.

Methods

Here, cultivation of Bt rice cultivar T1C-1, its parental cultivar Minghui 63, and the conventional cultivar Zhonghua11 was conducted in a randomized block design with nine replicate plots. The microorganisms, enzymes, and metabolites that were differentially abundant in soils from the 3 cultivars were evaluated with metagenomic and metabolomic analyses. The study aimed to elucidate the effects of Bt rice cultivation on soil microbial community characteristics.

Results

Cultivation of the Bt rice variety T1C-1 led to higher soil total nitrogen (TN), ammonium-N (NH₄⁺-N), nitrate-N (NO₃⁻-N), and nitrite-N (NO₂⁻-N) concentrations compared to soils of the parental cultivar Minghui 63. Metagenomic analyses revealed that rhizosphere bacterial community compositions significantly differed among cultivars, but this was not observed for fungal and nematode communities. The bacterial community Shannon diversity index was positively associated with soil nutrient multifunctionality (SNM) that was evaluated as the ability to perform multiple nutrient cycling processes. These results highlight the importance of biodiversity as a major driver of root microhabitat ecosystem functioning.

Conclusions

Metagenomic and metabolomic analyses suggested that Bt rice cultivation alters soil C and N cycling, possibly by influencing the functioning of soil microbiomes. Our results provide insight into ecological effects of the cultivation of Bt crops on soil community as well as key knowledge for their overall risk assessment.

中文翻译：

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土壤养分循环和微生物组对 Bt 水稻种植的反应

 目标和背景

根际微生物组的组成和功能取决于植物根系和土壤养分条件之间的相互作用。然而，植物物种遗传变异对根部相关微生物及其养分循环活动的影响仍然知之甚少。

 方法

在此，Bt 水稻品种 T1C-1、其亲本品种明恢 63 和常规品种中华 11 的栽培采用随机区组设计，有 9 个重复小区。通过宏基因组和代谢组分析评估了 3 个品种土壤中丰富程度不同的微生物、酶和代谢物。该研究旨在阐明 Bt 水稻种植对土壤微生物群落特征的影响。

 结果

种植 Bt 水稻品种 T1C-1 导致土壤总氮 (TN)、铵态氮 (NH ₄ ⁺ -N)、硝态氮 (NO ₃ ⁻ -N）和亚硝酸盐-N（NO ₂ ⁻ -N）浓度。分析表明，根际细菌群落组成在不同品种之间存在显着差异，但在真菌和线虫群落中没有观察到这种情况。细菌群落香农多样性指数与土壤养分多功能性（SNM）呈正相关，SNM 被评估为执行多种养分循环过程的能力。这些结果凸显了生物多样性作为根部微生境生态系统功能的主要驱动力的重要性。

 结论

宏基因组和代谢组分析表明，Bt 水稻种植可能通过影响土壤微生物组的功能来改变土壤碳和氮循环。我们的研究结果提供了有关 Bt 作物种植对土壤群落的生态影响的见解以及其整体风险评估的关键知识。