Knockdown of Helicoverpa armigera protease genes affects its growth and mortality via RNA interference

Abstract

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), the cotton bollworm, is a destructive pest which is famous for its resistance to a variety of insecticides. RNA interference is a posttranscriptional gene silencing mechanism that has become a popular tool to control insect pests, triggered by double-stranded RNAs (dsRNAs). The effect of ingestion and injection delivery methods of dsRNA related to some protease genes including Trypsin (Ha-TRY39 and Ha-TRY96), Chymotrypsin (Ha-CHY), and Cathepsin L (Ha-CAT) on growth and development of H. armigera was investigated in this study. All protease genes encoded full ORFs and were expressed in all H. armigera larvae stages and tissues. In both injection and feeding bioassays, Ha-RNAi CHY's performance outperformed that of other protease genes. CHY enzyme activity in the midgut of larvae was significantly reduced after treatment with ds-HaCHY. Oral administration of ds-CHY also resulted in significant mortality of H. armigera larvae.However, because of the high RNase activity in the midgut lumen of lepidoptera, a large amount of dsRNA was needed to effectively kill instars of H. armigera. To reduce dsRNA degradation, bacterial expression and dsRNA formulation were used. After oral administration, it was toxic to H. armigera larvae. Before oral administration, bacterial cells were sonicated to increase dsRNA release. The RNA interference efficiency of sonicated bacteria was significantly increased,

Methods for the Cost-Effective Production of Bacteria-Derived Double-Stranded RNA for in vitro Knockdown Studies

“…The system is mainly used for direct feeding of induced bacteria to research animals in a process termed bacterium-mediated RNA interference (bmRNAi) ( Timmons and Fire, 1998 ; Goodfellow et al, 2019 ; Kunte et al, 2020 ). Recent publications reaffirm its useability in the important lepidopteran pest genera Spodoptera and Helicoverpa ( Vatanparast et al, 2021 ; Wan et al, 2021 ; Wang et al, 2021 ).…”

Exogenous Application of dsRNA in Plant Protection: Efficiency, Safety Concerns and Risk Assessment

“…This includes their introduction into irrigation water or via trunk injections [ 24 , 25 , 26 , 27 ], as well as their incorporation into food baits. Innovative systems, such as the use of microorganisms, viruses, and nanocarriers [ 24 , 28 , 29 , 30 , 31 ] also facilitate their delivery. Second, dsRNA molecules can be applied topically in the form of spray-induced gene silencing (SIGS) [ 32 ].…”

Untargeted UHPLC-MS Metabolomics Reveals the Metabolic Perturbations of Helicoverpa armigera under the Stress of Novel Insect Growth Regulator ZQ-8

“…The damage caused by H. armigera to crops exceeds USD$ 2 billion annually [4]. However, the high reliance on traditional chemical insecticides to control H. armigera has resulted in the development of resistance to many insecticides [5,6]. Therefore, it is urgent to discover and develop new insecticides to achieve green prevention and control of H. armigera.…”