|JOOST, P HOUSTON|
Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/19/2004
Publication Date: 5/19/2004
Citation: Backus, E.A., Joost, P., Yan, F. 2004. Specific stylet activities by sharpshooters are involved in inoculation of Xylella fastidiosa. Phytopathology. 94(6):S6.
Technical Abstract: Glassy-winged sharpshooter (GWSS) feeding behavior is being studied to determine the exact behaviors associated with inoculation of the xylem-limited bacterium, Xylella fastidiosa (Xf) in plants. To do this, we are using electropenetration graph (EPG) monitoring of feeding, videomicrography of stylet movements in transparent diet and histology of Xf aggregations in vector precibaria. Studies on grape described last year showed preliminary correlations of GWSS waveforms A1 and A2 with salivary sheath formation, B1 and B2 with other pathway activities, and C with ingestion. They also implicated the B1 waveform in inoculation of Xf near EPG-identified probes. Work this year has emphasized understanding the biological meanings of sub-patterns in the B1 waveform and correlation of waveforms with bacterial populations in the vector precibarium. Results presented describe stylet activities during the 'spikelet burst' sub-pattern of B1, which may represent expulsion of bacteria-laden fluid from the precibarium. The ultimate goal of our research is to develop a Stylet Penetration Index using EPG monitoring of feeding, which could provide a rapid means of screening grape varieties for host plant resistance to the vector.