AUTHOR=Ibanez Freddy , Vieira Rocha Sâmara , Dawson William O. , El-Mohtar Choaa , Robertson Cecile , Stelinski Lukasz L. , Soares-Costa Andrea 

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

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1219319

DOI=10.3389/fpls.2023.1219319

ISSN=1664-462X

ABSTRACT=<p><italic>Diaphorina citri</italic> Kuwayama (Hemiptera: Liviidae) is a vector of the bacteria <italic>Candidatus</italic> Liberibacter americanus (<italic>C</italic>Lam) and <italic>Candidatus</italic> Liberibacter asiaticus (<italic>C</italic>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 <italic>D. citri</italic> 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 <italic>Citrus macrophylla</italic> plants targeting <italic>DCcathB</italic> and <italic>DCcathL</italic> genes in <italic>D. citri</italic> that fed on the phloem of these CTV-RNAi infected plants. Subsequently, we evaluated expression of <italic>DCcathB</italic> and <italic>DCcathL</italic> genes as well as the <italic>Vitellogenin</italic> (<italic>Vg)</italic> gene by RT-qPCR in <italic>D. citri</italic> fed on CTV-dsRNA occurring in plant phloem. It was found that a defective phenotype in <italic>D. citri</italic> females as a result of knockdown of <italic>DCcathB</italic> and <italic>DCcathL</italic> 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 <italic>DCcathB</italic> and <italic>DCcathL</italic> genes may represent a suitable avenue for development of dsRNA-based tools to manage <italic>D. citri</italic> that limits the spread of HLB.</p>