Abstract:

To elucidate the infection mechanism of Penicillium oxalicum strain FS-PNC isolated from the cadavers of infected brown planthoppers (Nilaparvata lugens)—against rice planthoppers, the green fluorescent protein (GFP) gene was introduced into FS-PNC via a polyethylene glycol (PEG)-mediated protoplast transformation method, successfully constructing the labeled strain FS-PNC-GFP. The mycelia, conidiophores, and conidia of the labeled strain stably expressed GFP, indicating successful integration and functional expression of the GFP gene in the fungal genome. Pathogenicity assays demonstrated that FS-PNC-GFP caused cumulative corrected mortality rates exceeding 70% for the third-instar nymphs and over 80% for the adults of three rice planthopper species: Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus. No significant differences in pathogenicity were observed among the three planthopper species, and the virulence of FS-PNC-GFP was comparable to that of the wild-type strain FS-PNC, indicating that GFP labeling did not affect its pathogenic activity. The GFP-tagged strain constructed in this study retains the high pathogenicity of the wild-type strain against rice planthoppers while offering excellent traceability, providing a key tool for further clarifying the infection pathways of FS-PNC and laying a foundation for optimizing its field application as a biocontrol agent and deeply exploring host-fungus interaction mechanisms.

Key words: rice planthopper, biocontrol fungus, green fluorescent protein

摘要：

为解析分离自染病褐飞虱（Nilaparvata lugens）虫尸的草酸青霉（Penicillium oxalicum）菌株FS-PNC对稻飞虱的侵染机制，本研究采用聚乙二醇（PEG）介导的原生质体转化法，将绿色荧光蛋白（GFP）基因导入FS-PNC，成功构建标记菌株FS-PNC-GFP。该标记菌株的菌丝、分生孢子梗和分生孢子均能稳定表达GFP，说明GFP基因已成功整合至基因组并实现功能性表达。致病力测定显示，FS-PNC-GFP对褐飞虱、白背飞虱（Sogatella furcifera）和灰飞虱（Laodelphax striatellus）的3龄若虫累积校正死亡率均超过70%，对成虫的累积校正死亡率均超过80%，且对三种稻飞虱的致病力无显著差异；FS-PNC-GFP与原始菌株FS-PNC的致病性相当，表明GFP标记未影响其致病活性。本研究构建的荧光标记菌株FS-PNC-GFP既保持了原始菌株对稻飞虱的高致病力，又具备良好的可视化示踪能力，为后续阐明FS-PNC侵入稻飞虱的途径提供了关键工具，也为优化该菌株的田间生物防治应用策略、深入探究菌株与寄主互作机制奠定了基础。

关键词: 稻飞虱, 生防菌, 绿色荧光蛋白