Gene silencing of cathepsins B and L using CTV-based, plant-mediated RNAi interferes with ovarial development in Asian citrus psyllid (ACP), Diaphorina citri .

Kuwayama (Hemiptera: Liviidae) is a vector of the bacteria Liberibacter americanus (Lam) and Liberibacter asiaticus (Las), which are phloem-restricted and associated with the most important and destructive worldwide citrus disease, Huanglongbing (HLB). Currently, no cure for HLB has been described. Therefore, measures have focused on reducing populations. In these insects, cathepsin B (DCcathB) and L (DCcathL) enzymes play an important role in digestion, and are involved in embryogenesis, immune defense, and ecdysis. In this study, we used a CTV-based vector to deliver dsRNA (CTV-dsRNA) into plants targeting and genes in that fed on the phloem of these CTV-RNAi infected plants. Subsequently, we evaluated expression of and genes as well as the ( gene by RT-qPCR in fed on CTV-dsRNA occurring in plant phloem. It was found that a defective phenotype in females as a result of knockdown of and genes mediated by CTV dsRNA. These results showed that Psyllids fed on plants treated with the CTV-dsRNA exhibited downregulation of the Vg gene, one of the most important genes associated with embryogenic and female development, which was associated with dsRNA-mediated silencing of the two cathepsin genes. Based on our findings, a CTV-based strategy for delivering RNAi via plants that targets and genes may represent a suitable avenue for development of dsRNA-based tools to manage that limits the spread of HLB.