2007 Annual Report
1a.Objectives (from AD-416)
Conduct research on aspects of vector biology and ecology of insects transmitting Pierce's disease and the causative Xylella fastidiosa bacterium, including approaches that utilize moecular tools that will facilitate development of management tools to reduce movement and spread of the vectors and the disease. Research will primarily focus on and have application to Pierce's disease on grapes grown in the Southeastern U.S., but will also be applicable to management of Pierce's disease in California. It is expected that the Ft. Pierce effort will coordinate closely with the ARS effort in Parlier, California.
1b.Approach (from AD-416)
Pierce's Disease, PD, is one of several economically important bacterial diseases caused by the pathogenic bacterium, Xylella fastidiosa, which is spread by the glassy-winged sharpshooter, and other leafhoppers. Piece's Disease is a limiting factor in the National grape production throughout the Southeastern
U.S. and California. Xylella also causes other "Scorch" diseases in many other tree crops and ornamentals. One such example is citrus variegated chlorosis, CVC, which is devastating to citrus, but has not yet been reported within the borders of the U.S. If not contained, PD will severely impact both the domestic and international viticultural markets. Therefore, we are studying aspects of vector biology, genetics, pathology, and potential biological control agents. Other methods of plant protections are also being studied, which includes insecticides, novel chemistries, germplasm improvement using disease and insect resistance genes in grapes will also be incorporated to develop an effective IPM strategy to reduce the economic impacts of PD and its leafhoper vectors. Vector-pathogen interactions will be biologically characterized. Current and emerging agricultural problems associated with leafhopper vectors of Xylella and other plant diseases will be incorporated into the research program.
4.Accomplishments
When no genomic data was available for leafhoppers, we used a genomics approach to sequence and identify thousands of expressed genetic sequences from three leafhopper species which were vectors of Pierce’s disease. The sequences from these leafhoppers provided the genomic information needed to build functional genomics tools, as microarrays for further analyses. These genetic products are being used to:. 1)Develop genetic markers for species biotyping,. 2)Elucidation of leafhopper feeding and digestion as relates to disease transmission.. 3)Provides the foundation for studies on leafhopper responses to pesticide development. National Programs Crop Protection and Quarantine, NP304, Research Component A. Insects and Mites, Component II- Biology of Pests and Natural Enemies (including microbes), Problem Area: IIA- Basic Biology. Previously searching for viral pathogens in leafhoppers has been difficult and costly due to problems in sampling and analysis of field caught insects. The gene microarray performs a wide screen across known insect viruses thus providing a rapid detection and identification of viruses detected in leafhopper samples. National Programs Crop Protection and Quarantine, NP304, Component II- Biology of Pests and Natural Enemies (including microbes), Problem Area: IIA- Basic Biology.
5.Significant Activities that Support Special Target Populations
None.
6.Technology Transfer
Number of web sites managed |
3 |
Number of non-peer reviewed presentations and proceedings |
9 |
Number of newspaper articles and other presentations for non-science audiences |
3 |
Review Publications
Mozoruk, J.J., Hunnicutt, L.E., Hunter, W.B., Bausher, M.G. 2007. CsV03-3, a gene that encodes a protein with DNA binding activity is a member of a novel gene family from Citrus sinensis whose expression is responsive to defense signals and abiotic stress.. Journal of Plant Physiology. Available: http:/www.ScienceDirect.com
Katsar, C.S., Hunter, W.B., Sinisterra, X.S. 2007. Phytoreovirus-like sequence isolated from Glassy-winged sharpshooter salivary glands, Homalodisca vitripennis (Hemiptera: Cicadellidae). Florida Entomologist.
90(1):169-203.
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