Table_1_Neutral Ceramidase Is Required for the Reproduction of Brown Planthopper, Nilaparvata lugens (Stål).XLSX

Ceramides are bioactive sphingolipids that have been implicated in insect development; however, their role in insect reproduction remains poorly understood. Here, we report the pivotal role of neutral ceramidase (NCER) in the female reproduction of the brown planthopper (BPH), Nilaparvata lugens (Stål), a significant pest in rice cultivation in Asia. LC-MS/MS demonstrated that, among different developmental stages of BPH, the levels of ceramides were highest in 1st instar nymphs and lowest in adults. The transcription of NCER was negatively correlated with the levels of ceramides at different developmental stages of BPH, in that the transcript levels of NCER were the highest, whereas ceramides levels were the lowest in BPH adults. Knocking down NCER through RNA interference (RNAi) increased the levels of ceramides in BPH females and ovaries, which resulted in a delay in oocyte maturation, a reduction in oviposition and egg hatching rate, as well as the production of vulnerable offspring. Transmission electron microscopy (TEM) analysis and TdT-mediated dUTP Nick-End Labeling (TUNEL) assays showed mitochondrial deficiency and apoptosis in NCER-deficient oocytes. Taken together, these results suggest that NCER plays a crucial role in female reproduction in BPH, likely by regulating the levels of ceramides.

神经酰胺（Ceramides）是一类具有生物活性的鞘脂，已被证实参与昆虫发育过程，但其在昆虫生殖中的作用仍未得到充分阐明。本研究以亚洲水稻种植区的重要害虫褐飞虱（brown planthopper，BPH，学名Nilaparvata lugens (Stål)）为研究对象，揭示了中性神经酰胺酶（neutral ceramidase，NCER）在其雌性生殖过程中的关键调控作用。液相色谱-串联质谱（LC-MS/MS）检测结果显示，在褐飞虱的不同发育阶段中，神经酰胺的含量在1龄若虫中最高，而成虫体内的神经酰胺水平最低。在褐飞虱的各发育阶段中，NCER的转录水平与神经酰胺含量呈负相关：成虫体内NCER的转录水平最高，而神经酰胺的含量则最低。通过RNA干扰（RNA interference，RNAi）敲低NCER的表达后，褐飞虱雌性成虫及其卵巢内的神经酰胺水平显著升高，进而导致卵母细胞成熟延迟、产卵量与卵孵化率降低，且子代个体生存能力减弱。透射电子显微镜（Transmission electron microscopy，TEM）分析与末端脱氧核苷酸转移酶介导的dUTP缺口末端标记测定法（TdT-mediated dUTP Nick-End Labeling，TUNEL）结果表明，NCER缺失的卵母细胞存在线粒体功能缺陷与细胞凋亡现象。综上，本研究结果表明，NCER在褐飞虱雌性生殖过程中发挥着至关重要的调控作用，其机制可能通过调节神经酰胺的水平实现。