Positively charged nanoplastics are more toxic to microorganisms than their negatively charged counterparts, prompting further investigation into their antimicrobial properties. While many studies have shown that positively charged nanoplastics bind to bacteria, the fate of these nanoplastic coatings during bacterial growth remains unclear. Here, we report how amine-modified polystyrene nanoplastics (PS-NH₂) reduce the viability of the plant growth-promoting rhizobacterium Bacillus subtilis and impair its ability to colonize plant roots. We found that upon exposure to PS-NH₂, the nanoplastics form stable, multilayer coatings on the surface of the bacteria. In response, B. subtilis initiates processes to remove these nanoplastics—a behavior heavily influenced by their growth environment, whether at air or liquid interfaces. Consequently, we observed differential toxicity under varying growth conditions. Using tomato plant as a model system, we found that these nanoplastics severely inhibit bacterial attachment to plant roots. Our results demonstrate that nanoplastics can disrupt beneficial interactions between soil bacteria and plants, potentially compromising the effectiveness of microbial biofertilizers. Given that current practices introduce large amounts of plastics into agricultural areas, the adverse effects of nanoplastic pollution need to be mitigated

中文翻译：

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枯草芽孢杆菌的适应性反应是差异纳米塑料毒性的基础，对根定植有影响


带正电荷的纳米塑料比带负电荷的纳米塑料对微生物的毒性更大，这促使对其抗菌特性的进一步研究。虽然许多研究表明带正电荷的纳米塑料与细菌结合，但这些纳米塑料涂层在细菌生长过程中的命运仍不清楚。在这里，我们报道了胺改性的聚苯乙烯纳米塑料 （PS-NH₂） 如何降低植物生长促进根瘤杆菌枯草芽孢杆菌的活力并损害其在植物根系定植的能力。我们发现，在暴露于 PS-NH₂ 后，纳米塑料会在细菌表面形成稳定的多层涂层。作为回应，枯草芽孢杆菌启动了去除这些纳米塑料的过程——这种行为深受其生长环境的影响，无论是在空气还是液体界面。因此，我们在不同的生长条件下观察到不同的毒性。以番茄植物为模型系统，我们发现这些纳米塑料严重抑制了细菌对植物根部的附着。我们的结果表明，纳米塑料会破坏土壤细菌和植物之间的有益相互作用，从而可能损害微生物生物肥料的有效性。鉴于目前的做法将大量塑料引入农业领域，需要减轻纳米塑料污染的不利影响