Molecular identification of the chitinase genes in Aedes albopictus and essential roles of AaCht10 in pupal-adult transition

Abstract

Background Aedes albopictus is an increasingly serious threat in public health due to it is vector of multiple arboviruses that cause devastating human diseases, as well as its widening distribution in recent years. Insecticide resistance is a serious problem worldwide that limits the efficacy of chemical control strategies against Ae. albopictus. Chitinase genes have been widely recognized as attractive targets for the development of effective and environmentally safe insect management measures. Methods Chitinase genes of Ae. albopictus were identified and characterized on the basis of bioinformatics search of the referenced genome. Gene characterizations and phylogenetic relationships of chitinase genes were investigated, and spatio-temporal expression pattern of each chitinase gene was evaluated using qRT-PCR. RNA interference (RNAi) was used to suppress the expression of AaCht10, and the roles of AaCht10 were verified based on phynotype observations, chitin content analysis and hematoxylin and eosin (H&E) stain of epidermis and midgut. Results Altogether, 14 chitinase-related genes (12 chitinase genes and 2 IDGFs) encoding 17 proteins were identified. Phylogenetic analysis showed that all these AaChts were classified into seven groups, and most of them were gathered into group IX. Only AaCht5-1, AaCht10 and AaCht18 contained both catalytic and chitin-binding domains. Different AaChts displayed development- and tissue-specific expression profiling. Suppression of the expression of AaCht10 resulted in abnormal molting, increased mortality, decreased chitin content and thinning epicuticle, procuticle and midgut wall of pupa. Conclusions Findings of the present study will aid in determining the biological functions of AaChts and also contribute to using AaChts as potential target for mosquito management. Graphical Abstract

Molecular identification and functional analysis of chitinase genes reveal their importance in the metamorphosis of Sarcophaga peregrina (Diptera: Sarcophagidae)

“…Similarly, in Ae. albopictus , suppression of AaCht10 expression resulted in abnormal pupal molting and increased mortality ( An et al 2023 ). The increased mortality was also observed during this experiment, although we did not record it explicitly in this research.…”

“…Chitinases belong to the family of 18 glycosylhydrolases ( Arakane and Muthukrishnan 2010 ). The homologs of these enzymes have been identified and characterized in various species, such as 14 genes in Bemisia tabaci (Hemipteran) ( Peng et al 2021 ), 11 genes in Agrotis ipsilon (Lepidopteran) ( Li et al 2022 ), 19 genes in Leptinotarsa decemlineata (Coleopteran) ( Chen et al 2023 ), and 14 genes in Aedes albopictus (Dipteran) ( An et al 2023 ). Additionally, several chitinases were found to be essential for insect survival, molting, and development ( Tachu et al 2008 , Zhang et al 2021 ).…”

Validamycin Inhibits the Synthesis and Metabolism of Trehalose and Chitin in the Oriental Fruit Fly, Bactrocera dorsalis (Hendel)

“…For example, the silencing a chitin synthase of Spodoptera frugiperda (Lepidoptera: Noctuidae) that is highly expressed in the cuticle caused a high rate of larval mortality and pupal malformation [ 20 ]. Additionally, inhibiting chitinase 10 ( Cht10 ) of Aedes albopictus (Diptera: Culicidae) expression led to abnormal molting, increased mortality; decreased chitin content; and thinning of the pupal epiculticle, endocuticle, and midgut wall [ 21 ]. Therefore, the chitin biosynthesis pathway has been recognized as a promising target for pest management [ 22 , 23 ].…”