Location: Emerging Pests and Pathogens Research
Project Number: 8062-22410-007-021-A
Project Type: Cooperative Agreement
Start Date: Sep 15, 2021
End Date: Sep 14, 2023
Many serious plant pathogens are dependent upon insect vectors for transmission between hosts. Targeting the relationships between insects and microbes is a major focus of research to manage insect vectors and insect-borne plant diseases. RNA and protein-based experimental systems offer innovative approaches to study and manage insects and insect-borne plant diseases that have been recalcitrant to the development of host resistance and for which the economic and environmental costs of control has been prohibitive, unsustainable and/or ineffective. Broadly, research will focus on insect vector-borne pathogens, including citrus greening disease and diseases caused by poleroviruses, such as cotton leafroll dwarf virus, that are transmitted by aphids. The objectives of this research are to 1. Develop RNA-based technology to control citrus greening disease, and 2. Develop protein based technology for the control of citrus greening disease.
Research in Objective 1 will focus on two sub-objectives. Objective 1.1. will focus on the analysis of small RNAs (sRNA) produced by the bacterial symbionts of the Asian citrus psyllid in response to the bacteria that causes citrus greening disease. ARS will determine the target genes within the psyllid regulated by symbiont sRNAs, the expression of sRNAs in different insect tissue, and their role in transmission of the citrus greening bacterium. Work in this objective will explore in planta delivery of RNA molecules from symbionts, which are living molecule delivery devices fixed to citrus trees that have been developed in the ARS lab. Objective 1.2. will focus on the analysis of Citrus tristeza virus constructs in citrus targeting the Asian citrus psyllid, vector of citrus greening disease. Cooperator will use enzyme-linked immunosorbent assay (ELISA) to characterize the plants, evaluate viral expression, and perform insect bioassays to determine whether viral constructs are insecticidal to the Asian citrus psyllid. These assays are routine for the collaborator. ARS will test the role of functional constructs in transmission of the CLas bacterium by the Asian citrus psyllid. In Objective 2, research will be performed to characterize insect neuropeptides that block psyllid feeding, plant establishment, development and CLas transmission. Cooperator will assist with the development of greenhouse experiments to perform epidemiological modeling on pathogen spread during insect neuropeptide treatment. Epidemiological modeling is routine for the cooperator.