摘要
内向整流钾离子通道(inwardly-rectifying potassium channels, Kir)在动物体内承担着重要的生理功能。有关昆虫Kir的研究虽然不多,但近5年来却取得许多重要进展,本文就昆虫Kir近年来的研究进展进行评述。目前对昆虫Kir的研究主要集中在双翅目与半翅目,对基因组的分析以及基因克隆研究表明,昆虫Kir基因数量较少,远低于哺乳动物。双翅目的冈比亚按蚊Anopheles gambiae与埃及伊蚊Aedes aegypti有5~6个Kir基因,黑腹果蝇Drosophila melanogaster仅3个Kir基因,半翅目的褐飞虱Nilaparvata lugens与热带臭虫Cimex lectularius也只有3个Kir基因,而大豆蚜Aphis glycines的Kir基因数则减少到2个,第3个Kir基因的丢失可能与其马氏管的退化有关。系统进化分析表明昆虫Kir具有3个亚家族,但与哺乳动物的7个Kir亚家族没有直系同源关系。尽管如此,昆虫Kir具有与哺乳动物Kir类似的基本结构特征:由4个亚基组成四聚体通道,每个亚基具有2个跨膜区(TM1与TM2),TM1与TM2之间具K^+选择过滤序列。昆虫的Kir基因主要在唾液腺与马氏管中高水平表达,Kir抑制剂可阻断唾液腺与马氏管的分泌活性,从而影响昆虫的取食与排泄活动并使昆虫致死,说明这2类组织器官的分泌活性与Kir有关,Kir介导的K^+跨膜转运驱动了这类组织中上皮细胞的分泌活动。更为重要的发现是氟啶虫酰胺对褐飞虱Kir具有很高的阻断活性,并影响其唾液分泌与排泄功能,证明了Kir就是该杀虫剂的分子靶标。最后本文还对昆虫Kir研究中存在的科学问题进行了分析,展望了开发靶向Kir的新型杀虫剂的研究前景。
Inwardly-rectifying potassium channels(Kir) play important roles in various tissues of animals. Although the research on insect Kir channels is limited, some important findings about insect Kir had been achieved in the recent five years, which were reviewed in this article. Until now the studies on insect Kirs have been mainly focused on the insect orders Diptera and Hemiptera. The analysis on genomic data and gene cloning demonstrated that insects have much fewer Kir genes than mammals. The dipteran insects Aedes aegypti and Anopheles gambiae harbor five to six Kir genes, Drosophila melanogaster has only three Kir genes, and the hemipteran insects Nilaparvata lugens and Cimex lectularius also have only three Kir genes. The number of Kir genes in soybean aphid(Aphis glycines) reduced to only two, and the third one was lost, which conjecturally is related with the degeneration of Malpighian tubules during the evolution of aphids. Phylogenetic analysis reveals that insect Kirs belong to three subfamilies;however, they are not orthologous to the seven subfamilies of mammal Kirs. Even so, insect Kirs have similar structural characteristics with mammal Kirs: insect Kirs are tetramer channels composed by four Kir subunits, each subunit has two transmembrane domains(TM1 and TM2), and K^+ selective filter sequence is present between TM1 and TM2. The Kir genes are highly expressed in salivary gland and Malpighian tubules of insects. Kir inhibitors, which block the inward potassium current of Kir in insects, suppress the secretion activities of salivary gland and Malpighian tubules, and therefore disrupt the processes of insect feeding and excretion, and finally lead to the death of insects. These results suggest that the secretion activities of salivary gland and Malpighian tubules are regulated by Kir, and the transmembrane transport of K^+ mediated by Kir drives the secretion activities in these epithelial cells. The most important discovery is that flonicamid, an insecticide with long-sought-after mode of action, has high blocking activity on Kir in N. lugens, and disrupts the physiological function of salivary gland and renal tubes. These results demonstrate that Kir is the molecular target of flonicamid, suggesting that Kir is the excellent insecticidal target. Finally, the author analyzed the emerging scientific issues in insect Kir research remaining to be solved and highlighted the research prospects on the development of new insecticides targeting at Kir channels.
作者
苏建亚
SU Jian-Ya(Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China)
出处
《昆虫学报》
CAS
CSCD
北大核心
2019年第6期756-768,共13页
Acta Entomologica Sinica
基金
国家重点研发计划(2017YFD0200505)
关键词
昆虫
内向整流钾离子通道
氟啶虫酰胺
杀虫剂靶标
马氏管
唾液分泌
Kir抑制剂
Insect
inwardly-rectifying potassium channel
flonicamid
insecticide target
Malpighian tubules
salivary secretion
Kir inhibitor
