The exogenous application of nanoscale biochar has great potential in agriculture to improve crop resistance to pathogens, although the mechanisms underlying this physiological response are unclear. We investigated the potential of nanoscale and conventional biochar amendment to induce resistance in Nicotiana benthamiana upon infection with the pathogen Phytophthora nicotianae. Nanoscale biochar synthesized at 350 °C (400 mg L⁻¹) from corn straw with a particle size of ∼160 nm had a beneficial role in the active immunity of N. benthamiana through the ethylene pathway to provide resistance to P. nicotianae infection; in leaf assays, lesion diameters were reduced by 9.26% as compared to controls. Mechanistically, a 20.3% increase in reactive oxygen species (ROS) from biochar NP amendment activated the ethylene pathway, followed by SA-induced systemic acquired resistance (SAR) expression. The SA-induced immunity increased over 10-fold in the two biochar NP treatments. In addition, the biochar NPs induced PR1-a to a significantly greater extent than did regular biochar particles. In an experiment with the plant elicitor 5-methoxyindole, biochar NPs served as a unique delivery platform to improve plant growth, over 105.3% in the shoot length and 41.2% in the root length after seed treatment with biochar NPs and 5-methoxyindole compared to the untreated controls. This study demonstrates the successful use of exogenous nanoscale biochar amendment to stimulate plant defense responses and subsequent resistance to the important pathogen P. nicotianae. This approach holds great promise as a new plant protection strategy in sustainable nano-enabled agriculture.

中文翻译：

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生物炭纳米颗粒诱导植物免疫及其诱导剂甲氧基吲哚在本氏烟草中的应用

纳米级生物炭的外源应用在农业中具有提高作物对病原体抵抗力的巨大潜力，尽管这种生理反应的机制尚不清楚。我们研究了纳米级和常规生物炭改良剂在感染病原体烟草疫霉后诱导本氏烟草抗性的潜力。在 350 ℃ (400 mg L ^-1 ) 条件下从粒径约为 160 nm 的玉米秸秆中合成的纳米级生物炭通过乙烯途径对本氏烟草的主动免疫具有有益作用，从而提供对烟草假单胞菌的抗性感染; 在叶片测定中，与对照相比，病变直径减少了 9.26%。从机制上讲，来自 biochar NP 修正的活性氧 (ROS) 增加了 20.3%，激活了乙烯途径，然后是 SA 诱导的全身获得性抗性 (SAR) 表达。在两种生物炭 NP 处理中，SA 诱导的免疫力增加了 10 倍以上。此外，生物炭 NPs 诱导PR1-a比普通的生物炭颗粒要大得多。在植物诱导剂 5-甲氧基吲哚的实验中，生物炭 NPs 作为一种独特的递送平台来改善植物生长，与生物炭 NPs 和 5-甲氧基吲哚处理种子相比，芽长超过 105.3%，根长超过 41.2%未经处理的对照。这项研究证明了外源性纳米级生物炭改良剂成功用于刺激植物防御反应和随后对重要病原体烟草假单胞菌的抗性。这种方法在可持续纳米农业中作为一种新的植物保护策略具有很大的前景。