Research Areas

Citrus Huanglongbing 2012-

Researcher: Eduardo Chumbinho de Andrade


New RNAi approaches to control the psyllid Diaphorina citri, vector of the causal agent of citrus Huanglongbing


Research Group 

Eduardo C. de Andrade (PhD), Virology and Plant Pathology, Embrapa labex – USA; Wayne Hunter (PhD), Insect vectors, USDA /ARS-USHRL; David Hall (PhD), Invasive insect pests, USDA /ARS-USHRL; Juliana Freitas Astua (PhD), Biotechnology, Embrapa Cassava and Fruit; and Caue Ribeiro de Oliveira (PhD), Nanotechnology, Embrapa Agricultural Instrumentation.



The citrus Huanglongbing (HLB), recognized as the most devastating citrus disease worldwide, was detected in Brazil in 2004 and United States in 2005. In both countries the disease is caused by Candidatus Liberibacter asiaticus (CaLas), transmitted by the psyllid specie Diaphorina citri. There is no identified genetic resistance in the genus Citrus, and the only way to reduce the spread of disease is the chemical control of the insect vector and removal of diseased plants. RNA interference (RNAi) comprises a natural mechanism of gene regulation and antiviral defense system in eukaryotic cells, and results in sequence-specific degradation of RNAs. Recent scientific studies demonstrate the feasibility of use RNAi-based strategies to control pest and pathogens in plants. The objective of Labex-USA (Citrus Huanglongbing) will be the development of a strategy to impair the HLB dissemination through the control of D. citri using RNAi approaches. At the end of this work is expected identify and validate target genes of the insect, as well as evaluate methodologies for delivering the interfering RNA molecules into the plant and insect uptake. 



The main objective is to achieve a way to control the dissemination of the causal agent of Huanglongbing (HLB), by controlling his insect vector, the psyllid Diaphorina citri, or compromising his transmission capacity. To achieve this goal, the specific objectives must be reached: (i) Screening for psyllid specific target genes that are essential for his survival; (ii) Screening for psyllid genetics determinants to CaLas transmission capacity; (iii) Validation of target genes regarding mortality and transmission abolishment; and (iv) Evaluation of different ways to delivering interfering RNAs (siRNA and/or dsRNA) by nanotechnology approaches.