Use of CTV (citrus tristeza virus) as a tool for gene silencing of cysteine peptidase Diaphorina citri, insect vector Huanglongbing (HLB) for the control of disease in citrus

Abstract

The Brazilian citrus industry is one of the most important agricultural activities for the world economy. Brazil is now the world's largest orange producer and the largest exporter of concentrated orange juice. Citrus plants are being constantly attacked by pests and pathogens, which causes considerable economic losses to citrus industries worldwide. Huanglongbing (HLB), or citrus greening, a disease that seriously threatens the citrus industry, has caused serious damage to citrus, because the contaminated plants have reduced fruit size, high degree of acidity and a lower percentage of juice. This disease is caused by the bacterium Candidatus Liberibacter spp (CLas) which colonizes the phloem vessels and is transmitted to citrus plants by insect Diaphorina citri, a pest that has spread in recent years, without an effective control method. In the absence of control strategies for CLas, emphasis has been on control of D. citri. Strategies for gene silencing using RNA interference have been used in recent years to explore the role of genes and control pests. Thus, this project proposes the silencing of Diaphorina citri cysteine peptidases by RNA interference using a transient expression vector based on Citrus tristeza virus (CTV). The coincident cohabitation in the phloem tissue by Clas, D. citri and CTV will allow to develop a transient expression system to mitigate HLB via interference RNA (RNAi). Considering that Diaphorina citri cysteine protease could be a potential target to control of this insect, either by direct application of dsRNA or by production of plants expressing dsRNA. These strategies will help to reduce the incidence of disease by controlling the insect. (AU)