Maria Teresa Fernandez-Luna, Iowa State University, Department of Entomology
Monday, 4:10 p.m. E164 Lagomarcino Hall
Abstract: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera), is an important pest of citriculture. The ACP vectors a bacterium that causes Huanglongbing (HLB) disease of citrus, which is difficult and costly to cure. The bacterium Bacillus thuringiensis (Bt) produces multiple toxins with activity against a diverse range of insects. In efforts to provide additional, Bt toxin-based control methods for the ACP vector of HLB, we screened multiple strains of Bt for toxicity against ACP. The trypsin proteolytic profiles of 37 toxin strains were characterized. Six Bt strains of 37 tested showed toxicity to adult ACP at 500 μg/mL of proteolytically activated toxin. One of the toxic strains was selected for LC-MS/MS identification of the individual Cry toxins expressed. Toxicity assays with individual toxins derived from the toxic strain showed that the activated form of two different Cry toxins was toxic to ACP. These Cry toxins will be modified with ACP gut-binding peptides to enhance toxicity against ACP. Isolation of ACP gut-binding peptides, confirmation of peptide binding to the ACP gut and identification of ACP gut proteins bound by these peptides will be described. Bt toxins with activity against ACP would provide a more sustainable and environmentally benign approach for management of ACP and the associated HLB disease than repeated application of broad-spectrum insecticides.