University Honors

Glassy-winged sharpshooters (GWSS), Homalodisca vitripennis, are an invasive species brought to California from the Southeastern United States. They are pests that serve as vectors for the bacterium Xylella fastidiosa - a pathogen of various plants of great economic importance for California, including grape and citrus. In grapes, X. fastidiosa causes Pierceís disease (PD), which famously eradicated over 40% of the Temecula grapevines in the 1980ís and continues to cause millions of dollars in losses to viticulture. In vitro experiments are essential for evaluating strategies to control GWSS, such as CRISPR. The goal of this experiment is to determine the optimal parameters for X. fastidiosa acquisition by GWSS via an artificial diet system and (Periwinkle) inoculation. Using the in vitro feeding system that was developed and validated by our lab. The ability of X. fastidiosa to colonize the GWSS precibarium and foregut was assessed after 2 and 4 hours of the acquisition-access period. DNA was extracted from GWSS heads and the polymerase-chain reaction (PCR) using specific primers was used to detect the presence of X. fastidiosa. The presence of bacteria on GWSS mouthparts was also assessed using fluorescence microscopy. Transgenic Green Fluorescent Protein (GFP) X. fastidiosa were injected into the stems of periwinkle plants. The location of GFP fluorescence signals in stem cross-sections at 2, 4 and 6 weeks after GFP-labeled X. fastidiosa inoculation was determined. The resulting data will lead to future acquisition/transmission experiments that will assess the ability of a gene-edited GWSS to acquire and transmit X. fastidiosa.