State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Pest Manag Sci. 2021 Sep;77(9):3990-3999. doi: 10.1002/ps.6422. Epub 2021 May 12.
Chilo suppressalis and Cnaphalocrocis medinalis are destructive rice pests co-occurring in major rice-growing areas in China. RNA interference (RNAi)-based insect-resistant genetically engineered (IRGE) crops provide a promising approach for pest management by suppressing gene expression or translation. A microRNA (miRNA)-mediated IRGE rice line expressing endogenous Chilo suppressalis miRNA Csu-novel-260, showing significant resistance against Chilo suppressalis, provides an attractive control strategy for Chilo suppressalis by suppressing the expression of the disembodied (dib) gene expression. However, whether this transgenic line also shows the resistance against Cnaphalocrocis medinalis remains unknown.
A spatiotemporal expression analysis of Csu-novel-260 in the transgenic rice line was performed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) to determine the paddy field pest exposure dose. In diet feeding assays, a chemically synthesized Csu-novel-260 agomir at 200 fmol g significantly inhibited Chilo suppressalis pupation. However, larval development, survival and pupal weight were not significantly affected. Additionally, the transgenic line significantly affected Cnaphalocrocis medinalis pupation but not larval survival. The qRT-PCR showed that Csdib and Cmdib expression levels were significantly suppressed when the two pests fed on the transgenic line. Additionally, the transgenic line significantly decreased Cry1C-resistant and Cry1C-susceptible Chilo suppressalis larval survival in detached rice tissue feeding assays, indicating that Cry1C-resistant Chilo suppressalis was not cross-resistant to Csu-novel-260 expressed in miRNA-mediated IRGE rice.
Our study demonstrated that miRNA-mediated IRGE rice significantly inhibited Chilo suppressalis and Cnaphalocrocis medinalis pupation. The results provide a new viewpoint for the application of RNAi-based plants and the inspiration for environmental risk assessment.
二化螟和稻纵卷叶螟是中国主要水稻种植区破坏性的水稻害虫。基于 RNA 干扰（RNAi）的抗虫转基因（IRGE）作物通过抑制基因表达或翻译为害虫管理提供了一种有前途的方法。表达内源性二化螟 miRNA Csu-novel-260 的 miRNA 介导的 IRGE 水稻品系表现出对二化螟的显著抗性，通过抑制 disembodied（dib）基因表达来提供一种有吸引力的二化螟控制策略。然而，这种转基因品系是否也对稻纵卷叶螟表现出抗性尚不清楚。
通过定量逆转录聚合酶链反应（qRT-PCR）对转基因水稻品系中 Csu-novel-260 的时空表达进行分析，以确定稻田害虫暴露剂量。在饮食喂养试验中，200 fmol g 的化学合成 Csu-novel-260 agomir 显著抑制二化螟化蛹。然而，幼虫发育、存活和蛹重没有受到显著影响。此外，该转基因品系显著影响稻纵卷叶螟的化蛹，但不影响幼虫存活。qRT-PCR 显示，当两种害虫以转基因为食时，Csdib 和 Cmdib 的表达水平均显著受到抑制。此外，在离体水稻组织喂养试验中，该转基因品系显著降低了 Cry1C 抗性和 Cry1C 敏感二化螟幼虫的存活率，表明 Cry1C 抗性二化螟对 miRNA 介导的 IRGE 水稻中表达的 Csu-novel-260 不具有交叉抗性。
本研究表明，miRNA 介导的 IRGE 水稻显著抑制了二化螟和稻纵卷叶螟的化蛹。结果为基于 RNAi 的植物的应用提供了一个新的视角，并为环境风险评估提供了启示。
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