State Key Laboratory of Rice Biology; Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Ministry of Agriculture, and Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Institute for Intelligent Bio/Chem Manufacturing (iBCM), ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejian, China.
Insect Mol Biol. 2022 Aug;31(4):391-402. doi: 10.1111/imb.12767. Epub 2022 Feb 24.
Sphingomyelinases (SMases) are a group of enzymes that catalyse the hydrolysis of sphingomyelins into ceramides and phosphorylcholine. They have been intensively investigated for their pathophysiological roles in mammals whereas much remains unclear about their counterparts in insects. Herein we report the cloning and functional characterization of four SMase homologue genes, designated NlSMase1-4, from brown planthopper (BPH). The phylogenetic analysis revealed that NlSMase1 and NlSMase2 were clustered into acid SMase family, and NlSMase3 and NlSMase4 with neutral SMase family. NlSMase1, NlSMase3 and NlSMase4 were highly expressed in BPH females, and NlSMaes2 in the 5th instar nymph. All four NlSMases had the lowest transcription in BPH males. NlSMase1 and NlSMase4 were highly expressed in BPH ovaries, while NlSMase2 and NlSMase3 in midgut and wings, respectively. Knocking-down of each NlSMase individual by RNA interference (RNAi) caused the ovarian malformation in BPH. The transcriptomic analysis revealed that NlSMase4 knockdown could strongly affect diacylglycerol (DAG)-related metabolisms and their downstream pathways. Further, qRT-PCR analysis of vitellogenin (Vg) genes indicates that the DAG metabolism disorder could interrupt the essential Vg accumulation for BPH oogenesis. Our study demonstrates the vital role of NlSMases in BPH reproductive development and provides new insights into the mediated mechanism of how SMases function.
鞘磷脂酶（SMases）是一组能够催化鞘磷脂水解为神经酰胺和磷酸胆碱的酶。它们在哺乳动物中的生理病理作用已得到深入研究，而昆虫中的相应酶仍有许多未知之处。本文从褐飞虱中克隆并鉴定了 4 种 SMase 同源基因，命名为 NlSMase1-4。系统进化分析显示，NlSMase1 和 NlSMase2 聚类到酸性 SMase 家族，NlSMase3 和 NlSMase4 聚类到中性 SMase 家族。NlSMase1、NlSMase3 和 NlSMase4 在褐飞虱雌虫中高表达，NlSMaes2 在 5 龄若虫中高表达。4 种 NlSMases 在雄虫中的转录水平均最低。NlSMase1 和 NlSMase4 在褐飞虱卵巢中高表达，NlSMase2 和 NlSMase3 在中肠和翅膀中高表达。每种 NlSMase 的 RNAi 敲低均导致褐飞虱卵巢畸形。转录组分析显示，NlSMase4 的敲低可强烈影响二酰基甘油（DAG）相关代谢及其下游途径。进一步对卵黄蛋白原（Vg）基因的 qRT-PCR 分析表明，DAG 代谢紊乱可能会中断褐飞虱卵发生所必需的 Vg 积累。本研究证明了 NlSMases 在褐飞虱生殖发育中的重要作用，并为 SMases 如何发挥作用的介导机制提供了新的见解。
