In symbiont therapy, an insect's natural symbionts are genetically modified to prevent the transmission of a pathogen, and this strategy is currently under investigation as a way to control the spread of Pierce's disease of grapevine. The disease is caused by Xylella fastidiosa and is transmitted by the glassy-winged sharpshooter (GWSS; Homalodisca vitripennis). Within this framework, any approach must of necessity take into account the disease-causing organism, the symbiotic community that is present within the insect, and the grapevines themselves, along with their endophytic community. However, this work focused primarily on the bacterial symbionts in the insects and in the grapevines.
The first part of this research involved the use of genetic techniques to help determine the genetic identity and relatedness of five Alcaligenes xylosoxidans denitrificans species isolated from GWSS and previously identified only through biochemical and morphological testing. The results of this study showed that these species were most closely related to Pseudomonas stutzeri. In the second part of this research, members of the bacterial community inside GWSS heads were identified using 16S sequencing, both in order to find candidate symbionts and to learn more about the microbial ecology of the GWSS foregut. Members of the genera Methylobacterium and Bacillus were most frequently isolated in this study. The last part of this research involved using 16S analysis to investigate the makeup of the endophytic bacterial communities in grapevines apparently resistant to PD. In this study, members of the genus Paenibacillus were isolated more often from the asymptomatic vines than from the symptomatic vines.
|School:||University of California, Riverside|
|School Location:||United States -- California|
|Source:||DAI-B 69/06, Dissertation Abstracts International|
|Subjects:||Molecular biology, Cellular biology, Microbiology, Plant pathology|
|Keywords:||Grapevine, Pierce's disease, Symbiotic bacteria, Xylella fastidiosa|
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