Identification and RNA Interference-Based Functional Analysis of Chitin Deacetylase Genes in Bemisia tabaci

Chitin deacetylases (CDAs) play important roles in the growth and development of insects. In this study, four genes encoding chitin deacetylases (BtCDAs) were identified and characterized in the genome of the whitefly Bemisia tabaci MEAM1 cryptic species through bioinformatic annotation. Phylogenetic analysis showed that insect chitin deacetylases could be divided into five groups, with no Group II, IV, or V CDAs found in B. tabaci. Investigation of the developmental expression patterns of the four BtCDAs revealed that BtCDA1, BtCDA2a, BtCDA2b, and BtCDA4 were expressed at varying levels during the egg and nymph stages, with extremely low expression levels in adults. Delivery of dsRNA targeting BtCDA1, BtCDA2a/b, and BtCDA4 to fourth-instar nymphs of B. tabaci using the nanomaterial SPc resulted in significant gene silencing and mortality. A fusion gene of the three BtCDAs was designed based on the four BtCDA genes and subjected to RNAi experiments, demonstrating that both transgenic tomato and SPc-mediated delivery of fusion gene dsRNA could silence all BtCDA genes. These preliminary results indicate that the RNAi targeting of BtCDAs leads to substantial mortality in B. tabaci, highlighting the potential of BtCDAs as effective targets for RNAi-based pest management strategies.