近年来，纳米技术在农业领域中的应用越来越广泛，主要包括植物营养、植物保护、提高植物适应性、改善土壤结构和健康、纳米传感器和纳米生物技术等方面。其中，纳米颗粒可以刺激植物产生免疫作用受到了广泛关注。目前关于植物免疫研究中使用的纳米颗粒多为金属或非金属氧化物，其作用机制主要为通过ROS以及激素的变化调控植物的免疫网络，而关于碳基纳米颗粒引起植物免疫作用的机制还缺乏深入研究。因此，完善纳米颗粒刺激植物产生抵抗生物胁迫的能力与植物免疫的分子机制对于评估纳米技术在农业应用中的潜在应用及其环境生态安全性具有重要意义。

本文主要探究了不同浓度的氧化石墨烯（GO）和单壁碳纳米管（SWNT）对植物抵抗生物胁迫的影响。通过测定植物生理生化指标、植物激素及调控基因的表达，阐明两种碳基纳米颗粒对植物免疫的刺激作用与相关机理，并结合纳米颗粒自身不同的理化性质分析其免疫机制差异的原因。具体研究结果如下：

（1）GO、SWNT均能刺激拟南芥的免疫响应，应对植物致病菌丁香假单胞菌DC3000（PST）的入侵。结果表明GO、SWNT的预暴露可以有效减少植物中丁香假单胞菌的数量并抑制其在植物体内的繁殖，GO、SWNT处理组中丁香假单胞菌数量分别降至PST组的3.6%-11.2%。

（2）GO、SWNT可激活植物水杨酸（SA）相关的免疫通路抵抗病原体的入侵。纳米颗粒进入植物细胞后，细胞溶质钙离子水平增加并激活钙依赖性蛋白激酶，继而引起还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）与过氧化氢含量显著提升，在植物体内产生活性氧（ROS），激活植物抗氧化系统，同时通过上调SA转录因子NPR1和SA响应基因PR1、PR2、PR5，促进SA的生物合成和积累。如GO组和SWNT组的SA含量比PST组分别提高了1.5-5.5倍，从而提高植物对丁香假单胞菌的抗性。

（3）GO、SWNT刺激植物产生免疫作用时，还诱导了茉莉酸（JA）相关的免疫通路，促进了JA合成基因AOS、LOX2、THI2.1的表达，提高了植物内JA含量，如GO组和SWNT组中的JA含量比PST组分别提高了2.4-5.1倍。

（4）GO、SWNT短时间内产生了对植物局部的机械损伤，进而刺激植物免疫作用。GO、SWNT诱导了植物中损伤相关基因TCH4、WRKY40、WRKY53的高表达，具体表现为SWNT（10 mg/L）组>GO（10 mg/L）组>SWNT（1 mg/L）组>GO （1 mg/L）组。同时，机械损伤将钙离子和ROS信号从损伤局部传递到植物各个部位，激活了远距离的免疫反应，包括促进JA合成，增加脱落酸含量。SWNT的机械损伤效应略强于GO可能与其管状结构、相对易于在植株内传输相关。

本文的创新点在于阐明了GO、SWNT刺激植物免疫抵抗丁香假单胞菌入侵的相关机制，完善了生物胁迫下纳米颗粒促发植物免疫的相关机理，为农业生产中使用纳米生物刺激剂等新技术提供了重要的理论基础。

In recent years, nanotechnology has found extensive applications in agriculture, particularly in enhancing plant nutrition, protection, adaptability, soil health, as well as the development of nanosensors and genetic modulators. Among these applications, nanoparticles, including metallic and nonmetallic oxides, have been extensively studied for their immune-stimulating effects on plants. The mechanism behind these effects involves the regulation of the plant immune network through reactive oxygen species (ROS) and hormonal changes. However, the specific mechanism of plant immunity induced by carbon-based nanoparticles remains largely unknown. Therefore, it is crucial to gain a better understanding of the molecular mechanisms involved, as this knowledge can provide valuable insights for assessing the potential applications of nanotechnology in agriculture and its environmental and ecological impacts.

To explore the effects of graphene oxide (GO) and single-walled carbon nanotubes (SWNT) on plant resistance against biological stress, we conducted investigations that encompassed measurements of plant physiological and biochemical properties, changes in plant hormones, and gene expression levels. By elucidating the mechanisms by which SWNT and GO influence plant immunity, we were able to analyze the different levels of stimulation provided by these nanoparticles based on their distinct physical chemistry. The following are the main conclusions drawn from our study:

1) Both GO and SWNT elicited immune responses in Arabidopsis thaliana against Pseudomonas syringae DC3000. Pre-exposure to GO and SWNT effectively reduced the number of Pseudomonas syringae within plants and suppressed their reproduction. Compared to the control group, the number of Pseudomonas syringae decreased to 3.6 - 11.2% following exposure to GO and SWNT.

2) GO and SWNT can activate salicylic acid (SA)-related immune pathways, enhancing plant defenses against pathogen invasion. We observed an increase in solute Ca²⁺ levels and the activation of Ca-dependent protein kinase (CDPK), which in turn triggered the enhanced activity of NADPH oxidase RBOHD, leading to elevated production of H₂O₂. The elevated levels of reactive oxygen species (ROS) were accompanied by the activation of the plant antioxidant system. Simultaneously, the biosynthesis and accumulation of SA were promoted, enhancing plant resistance to Pseudomonas syringae through the upregulation of the SA transcription factor NPR1 and the SA response genes PR1, PR2, and PR5. Notably, the SA content in the GO- and SWNT-treated groups was 1.5-5.5 times higher compared to the control group.

3) GO and SWNT also induce jasmonic acid (JA)-related immune pathways, stimulating the expression of JA synthesis genes, such as AOS, LOX2, and THI2.1, and increasing the levels of JA in the plants. For instance, the JA content in the GO- and SWNT-treated groups increased by a factor of 2.4 and 5.1, respectively, compared to the control group.

4) GO and SWNT stimulate plant immunity by causing localized mechanical damage to plants. Exposure to GO and SWNT resulted in the upregulation of TCH4, WRKY44, and WRKY53 gene expression in plants, with the order of upregulation being SWNT (10 mg/L) > GO (10 mg/L) > SWNT (1 mg/L) > GO (1 mg/L). The transportation of injury signaling molecules, such as Ca²⁺ and ROS, from the site of injury to various parts of the plant activated the JA-related immune response and increased the abscisic acid (ABA) content.

This study's novelty lies in unraveling the mechanisms by which GO and SWNT stimulate plant immunity against Pseudomonas syringae. The improved understanding of plant immunity induced by nanoparticles provides critical information for potential applications of nanotechnology in enhancing plant defenses.