摘要
七星瓢虫Coccinella septempunctata是一种典型的优良捕食性天敌昆虫,广泛应用于害虫生物防治领域。该昆虫以滞育态成虫越冬,滞育态雌虫腹部脂质大量积累,存活时间显著延长。脂质积累是昆虫进入滞育状态的主要生理特征之一,积累的脂质为昆虫种群在滞育期和滞育解除后的基本代谢活动提供营养和能量,以应对能量物质匮乏的不利环境,从而确保其在恶劣环境中的生存。本试验的前期研究发现,滞育态七星瓢虫腹部积累的脂质主要是三酰甘油(triacylglycerol,TAG)。二酰甘油酰基转移酶(diacylglycerol-O-acyltransferase,DGAT)是TAG合成最后一步的催化酶,也是唯一限速酶。然而,人们对昆虫中的DGAT知之甚少。本研究从七星瓢虫基因组中筛选到了一个注释为二酰甘油酰基转移酶1(diacylglycerol acyltransferase 1,DGAT1)的基因序列。以七星瓢虫为研究对象克隆了二酰甘油酰基转移酶1基因(CsDGAT1)的ORF阅读框序列,并进行了生物信息学分析,利用RT-qPCR分析了该基因在滞育诱导雌虫和非滞育雌虫中的表达特征;利用RNAi技术干扰CsDGAT1基因,测量了干扰后雌虫体内TAG含量。研究结果表明:七星瓢虫CsDGAT1蛋白与异色瓢虫的CsDGAT1蛋白亲缘关系较近,并且含有8个保守的活性组氨酸位点。在非滞育条件下,CsDGAT1基因在雌虫脂肪体和卵巢中表达量较高;在滞育诱导条件下,CsDGAT1在雌虫脂肪体和中肠中表达量较高。与非滞育条件下的雌虫相比,CsDGAT1基因在滞育诱导的雌虫的脂肪体和中肠中表达量显著增加。RNA干扰CsDGAT1基因后,雌虫体内TAG含量显著降低,脂肪积累减少。本研究发现CsDGAT1基因在滞育态七星瓢虫的脂质积累中发挥重要作用,为深入探究七星瓢虫滞育的脂肪积累机制研究奠定基础。为开发诱导天敌昆虫滞育等技术提供理论支撑,对推进天敌昆虫在生物防治中的产业化应用具有重要作用。
Coccinella septempunctata is widely used predatory natural enemy insect in biological pest control.It survive the winter as a diapause adult,during which females accumulate substantial abdominal lipids,significantly prolonging survival.Lipid accumulation is a feature of insect diapause,supplying energy and nutrients for basic metabolism during the diapause period and post-diapause recovery,thereby enhancing survival under unfavorable conditions.Previous studies revealed that triacylglycerol(TAG)is the main lipid form in diapause females of C.septempunctata,with significantly increased TAG levels.Diacylglycerol-O-acyltransferase(DGAT),the terminal and rate-limiting enzyme in TAG synthesis,remains poorly studied in insects.In this study,we identified a gene encoding DGAT1(CsDGAT1)based on the genome of C.septempunctata.The full-length ORF of CsDGAT1 was cloned and analyzed via bioinformatics.RT-qPCR was used to examine its expression profile in diapause-induced and non-diapause females,and RNAi was employed to knock down CsDGAT1 expression and assess the effect on TAG content.Phylogenetic analysis showed that CsDGAT1 is closely related to DGAT1 from Harmonia axyridis and contains eight conserved histidine residues.Under non-diapause conditions,CsDGAT1 was highly expressed in the fat body and ovary;under diapause-induced conditions,it was primarily expressed in the fat body and midgut.CsDGAT1 expression was significantly upregulated in fat body and midgut of diapause-induced females compared to non-diapause females.RNAi-mediated silencing of CsDGAT1 significantly reduced TAG levels and fat accumulation.These results demonstrate that the CsDGAT1 plays an important role in lipid accumulation in diapausing females,providing a molecular basis for understanding diapause-related lipid metabolism and a theoretical foundation for developing diapause-induction technologies for natural enemy insects in biological control.
作者
陈俊杰
韩舜达
董文静
郭鹏辉
刘晓晓
刘照涵
张礼生
CHEN Junjie;HAN Shunda;DONG Wenjing;GUO Penghui;LIU Xiaoxiao;LIU Zhaohan;ZHANG Lisheng(State Key Laboratory for Biology of Plant Diseases and Insect Pests,Key Laboratory of Natural Enemy Insects,Ministry of Agriculture and Rural Affairs,Institute of Plant Protection,Chinese Academy of Agricultural Sciences,Beijing 100193,China;Shanghai Veterinary Research Institute,Chinese Academy of Agricultural Sciences,Shanghai 200241,China;College of Horticulture and Gardening,Tianjin Agricultural University,Tianjin 300392,China)
出处
《植物保护》
北大核心
2025年第4期53-62,130,共11页
Plant Protection
基金
国家重点研发计划(2023YFD1400600)
中国农业科学院科技创新计划(CAAS-ZDRW202203)
中国博士后科学基金(2024M763614)。
关键词
七星瓢虫
二酰甘油酰基转移酶1
脂质积累
滞育
表达特征
RNA干扰
Coccinella septempunctata
diacylglycerol-O-acyltransferase l
lipid accumulation
diapause
gene expression
RNA interference
