Genome‐wide identification, characterization and functional analysis of the chitianse and chitinase‐like gene family in Diaphorina citri

• Published in: Pest management science 2022-04, Vol.78 (4), p.1740-1748
• Main Authors: Wu, Zhong‐Zhen, Zhang, Wan‐Ying, Lin, Yi‐Zhu, Li, Da‐Qi, Shu, Ben‐Shui, Lin, Jin‐Tian
• Format: Article
• Language: English
• Subjects: 20‐hydroxyecdysone; Animals; Chitinase; Chitinases - genetics; Diaphorina citri; Functional analysis; Gene expression; Genes; Genomes; Hemiptera; Insects; Integument; Midgut; Molting; Molting - genetics; Nymph - genetics; Pests; RNA Interference; RNA-mediated interference; RNAi; Transcriptomes
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6793

BACKGROUND Insect chitinases play vital roles in postembryonic development, especially during the molting process, and are potential targets for the RNA interference (RNAi)‐based insecticidal strategy. Systematic functional analyses of chitinase genes have already been conducted on numerous insect pests, but similar analyses have not been carried out on Diaphorina citri. RESULTS Eleven chitinase/chitinase‐like genes and one endo‐β‐N‐acetylglucosaminidase (ENGase) gene were identified in the Diaphorina citri genome using various bioinformatic tools. Transcriptomes of the integument and midgut from fifth‐instar nymphs and freshly‐emerged adults of Diaphorina citri were generated and sequenced. Potential functions of 12 chitinase/chitinase‐like genes were examined during nymph–adult transitions. Four chitinase genes, including DcCht5, DcCht7, DcCht10‐1 and DcCht10‐2, were mainly expressed in the integument of fifth‐instar nymphs. These four genes were also up‐regulated significantly under 20‐hydroxyecdysone (20E) treatments. RNAi‐mediated knockdown of these four genes suggests that they are essential for nymph–adult transition. CONCLUSION Our results demonstrated essential roles of the chitinase/chitinase‐like genes during the nymph–adult transition in Diaphorina citri, which are potentially useful targets for controlling the Diaphorina citri pest. © 2022 Society of Chemical Industry In this study, 11 chitinase and chitinase‐like genes were identified in the Diaphorina citri genome, and classified into eight distinct phylogenetic groups. Pattern expression analysis showed that four chitinase genes (DcCht5, DcCht7, DcCht10‐1 and DcCht10‐2) displayed higher expression levels in the integument of fifth‐instar nymphs. Also, these genes were up‐regulated significantly under 20‐hydroxyecdysone treatment. The silencing of these genes resulted in molting defects and lethality during the nymph–adult transition. Specifically, RNA interference inhibited the expressions of DcCht10‐2 which showed more obvious effect on morphological phenotype.