昆虫几丁质合成酶基因转录调控研究进展

Advances in Transcriptional Regulation of Insect Chitin Synthase Genes

几丁质广泛存在于真菌、昆虫和甲壳类动物中,但不存在于植物和脊椎动物中,为昆虫外骨骼、气管及中肠围食膜的重要组分。昆虫蜕皮过程中,富含几丁质的结构需重建以完成虫体扩张,这一过程中需要严格控制几丁质的合成。因此,几丁质生物合成一直是害虫控制的重要靶标。随着昆虫种群耐药性的迅速发展,害虫防控面临新的挑战,需要不断寻找新的害虫防治靶点,以开发新型杀虫剂,实现害虫的有效防控。几丁质合成酶(Chitin synthase,CHS)为昆虫几丁质合成途径的关键酶,在几丁质合成中发挥重要作用。昆虫存在CHS1和CHS2两类几丁质合成酶,CHS1在昆虫外骨骼及气管中表达,催化几丁质合成,CHS2则主要负责中肠围食膜的几丁质合成。昆虫CHS1基因受干扰后可导致虫体表皮产生缺陷,背气管干发育异常,而CHS2基因受到抑制后则往往会导致虫体中肠变短,体重下降。两类CHS基因下调均可引起昆虫大量死亡。昆虫体内具有复杂的CHS转录调控机制以保证其正常生长发育和应对外界刺激。根据国内外研究,该文综述了昆虫CHS基因转录调控研究进展,包括昆虫激素、转录因子、表皮损伤及进食刺激、几丁质代谢相关基因及物质、microRNA以及几丁质合成抑制剂等对昆虫CHS mRNA水平的影响,为将来开发和利用以CHS为靶标的绿色农药防治害虫提供理论依据。

Chitin is widely found in fungi,insects and crustaceans,but not in plants and vertebrates.It is an important component of insect exoskeleton,trachea and midgut peritrophic membrane.During the molting process of insects,chitin-rich structures need to be reconstructed to complete the expansion of the insect body,and the synthesis of chitin needs to be strictly controlled.Therefore,chitin biosynthesis has been an important target for pest control.With the rapid development of pesticide resistance in insect populations,pest prevention and control is facing new challenges,and it is necessary to constantly search for new pest control targets to develop new insecticides and achieve effective pest control.Chitin synthase(CHS)is a key enzyme in insect chitin synthesis pathway and plays an important role in chitin synthesis.There are two kinds of chitin synthases,CHS1 and CHS2.CHS1 is expressed in the exoskeleton and trachea of insects and catalyzes chitin synthesis,while CHS2 is mainly responsible for chitin synthesis in the midgut peritrophic membrane.Interference of CHS1 can lead to defects in insect epidermis and abnormal development of dorsal trunk of tracheae,while the inhibition of CHS2 often results in shorter midgut and weight loss.Down-regulation of both CHS genes in insects could cause a large number of deaths.Insects have complex transcriptional regulation mechanisms of CHS to ensure their normal growth and development,and respond to external stimuli.Based on domestic and foreign studies,we reviewed the research progress in transcriptional regulation of insect CHS,including the effects of insect hormones,transcription factors,epidermal injury and feeding stimulation,genes and substances related to chitin metabolism,microRNA,and inhibitors of chitin synthesis on CHS mRNA levels in insects,with an aim to provide a theoretical basis for the development and utilization of green pesticides targeting CHS for pest control in the future.