Source: UNIVERSITY OF CALIFORNIA, OAKLAND submitted to NRP
PIERCE'S DISEASE (CA)
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
SPECIAL GRANT
Reporting Frequency
Annual
Accession No.
0207230
Grant No.
2006-34442-17146
Cumulative Award Amt.
(N/A)
Proposal No.
2006-06174
Multistate No.
(N/A)
Project Start Date
Jul 15, 2006
Project End Date
Jul 14, 2009
Grant Year
2006
Program Code
[QN]- (N/A)
Recipient Organization
UNIVERSITY OF CALIFORNIA, OAKLAND
1111 FRANKLIN, 6TH FLOOR
OAKLAND,CA 94607
Performing Department
INDEPENDENT
Non Technical Summary
Pierce's disease of grapevines causes significant losses in many areas where grapes are grown. The introduction and establishment of the glassy-winged sharpshooter, a highly efficient vector of the Pierce's disease bacterium into California and other grape producing states poses a devastating threat to the viticulture industries of those areas. The purpose of the Pierce's disease research program is to coordinate a research program to develop lasting control measures for Pierce's disease of grapevines and its vectors.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2031131106035%
2041131106010%
2051131106035%
4021131106010%
6011131106010%
Knowledge Area
601 - Economics of Agricultural Production and Farm Management; 204 - Plant Product Quality and Utility (Preharvest); 205 - Plant Management Systems; 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants; 402 - Engineering Systems and Equipment;

Subject Of Investigation
1131 - Wine grapes;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
The objective of this proposal is to continue and expand the University of California Pierce's Disease Research Grants Program that is currently under way. The research program was established in 2001 to coordinate a peer-reviewed competitive research grants program to address the needs of the California grape industry in combating the current Pierce's disease crisis. The threat of Pierce's disease has been exacerbated by the introduction, establishment, and spread of the glassy-winged sharpshooter, an additional more effective and dangerous vector of the Pierce's disease pathogen, Xylella fastidiosa. Researchers have and will continue to be sought from Agricultural Experiment Stations and universities across the country where pertinent expertise exists.
Project Methods
In 2001, the University of California established a peer-reviewed competitive research grants program that would address needs in combating Pierce's disease under the management of a project director and a guidance committee. The guidance committee is comprised of industry, research, and extension personnel. Their charge and responsibilities include identification of the current status of research and the research needed to address both the short and long term needs for Pierce's disease control. The project director and the guidance committee will develop a request for research proposals designed to address the research needs in the current Pierce's disease crisis. Research needs and priorities are derived from a variety of sources, including the 2004 National Academy report California Agricultural Research Priorities: Pierce's Disease; annual conferences (2001 to 2005) sponsored by the Pierce's Disease Research Grant Program and the California Department of Food and Agriculture (CDFA) Pierce's Disease Control Program; the 'Report of the University of California Pierce's Disease Research and Emergency Response Task Force' appointed by UC President R.C. Atkinson (April 2000); and the deliberations of a conference of U.S. and international scientists 'Pierce's Disease and the Glassy-winged Sharpshooter in California: Reviewing and Defining Critical Research' sponsored by the University of California. The request for proposals will be distributed to Agricultural Experiment Station directors throughout the U.S. and to other universities and agencies with evidence of strong viticulture and Pierce's disease research capacity, and to previous applicants. Directors and deans will be asked to circulate the request to appropriate scientists within their organizations. Proposal submission will be electronic, through the Pierce's Disease Grant Management System Web site. A parallel grant program is being funded by a grower levy and managed by the California Department of Food and Agriculture. Reviews of proposals to both programs are being coordinated through a joint submission process. Scientific review panels of knowledgeable researchers will be formed to evaluate and rate the proposals submitted to the grants program. We will also request ad hoc reviews of the proposals from other scientists to assist the scientific review panels. Reviews from both panel members and ad hoc reviewers will be submitted online through the grants management Web site. Information from all reviews will be considered in making funding recommendations. The criteria for evaluation and rating of proposals will include consideration of established research priorities; the appropriateness of the proposal to meet those needs; an evaluation of the scientific merit, experimental design, and adequacy of the personnel and facilities to insure the fulfillment of the objectives of the proposal. The guidance committee, upon receipt of the scientific review panel's evaluations and recommendations, will make recommendations to the Principal Investigator/Project Director for funding.

Progress 07/15/06 to 07/14/09

Outputs
OUTPUTS: Seventeen 1-2 yr projects were supported, aimed at mitigating Pierce's disease (PD) of grapevine (VITIS VINIFERA). The PD causative agent is XYLELLA FASTIDIOSA (Xf) bacterium, vectored by sharpshooters (glassy winged and blue-green sharpshooters, GWSS and BGSS). Project categories, A-D: (A)GRAPEVINE RESISTANCE TO Xf: Principal investigator (PI) Gilchrist used the genetically programmed cell death (apoptosis) inducer fumonisin B1 and a transformed root generation system to identify transgenes that have significant sparing effects against invasion by specific pathogens. Using molecular markers, PI Ramming introgressed resistance from VITIS ARIZONICA to create Xf-resistant, 93% V. VINIFERA lines. (B)REDUCING SHARPSHOOTER TRANSMISSION OF Xf: PI Falk found that double-stranded RNA containing a partial actin mRNA sequence, when introduced into GWSS cells in culture or by injection into GWSS nymphs, resulted in adverse outcomes for cells and nymphs. PI Byrne assessed neonicotinoid insecticide affects on various life stages of GWSS, finding insecticide doses effective against the nymph but sparing of the parsitoid-supporting GWSS egg. PI Almeida showed that increasing sharpshooter numbers, but not infected plant access time, increased Xf transmission frequency to grapevine. Source plant characteristics (PI Danne) and GWSS saliva enzymes (PI Backus) were examined for their relationship to Xf transmission. PI Triapitsyn discovered two new species of Gonatocerus egg parasitoids of sharpshooters and prepared a key and atlas of the Gonatocerus egg parasitoids from south of the US. (C)Xf VIRULENCE: The offensive and defensive capabilities of Xf allow its survival in the plant and are associated with pili and the secretion of specific molecules from the Xf cell. PI Igo's group mutated genes of Xf Type V polypeptide secretion, reducing Xf virulence in grapevine significantly, but leaving the Xf generation time in culture unaffected. PI Gabriel has focused on Type I secretion, which is involved with the efflux of toxic substances Xf might encounter in the host plant and the secretion of anti-bacterial proteins. Mutational inactivation of various Type I secretion components decreased or nearly eliminated Xf virulence. PI Hoch's group found that mutations in pili genes do not alter aggregation of Xf cells, but Type IV (long) pili appear to be necessary for formation of Xf migratory "rafts." PI Burr's results show that Xf cells lacking either Type IV or Type I (short) pili have reduced capabilities for biofilm formation and that Xf cells close to the biofilm sutface, but not those of the interior, are alive. (D)RESERVOIRS OF Xf: PI Almeida's measured alfalfa Xf titers were great enough for alfalfa to be a PD reservoir. PI Sisterson's result showed that <0.2% of alfalfa plants were Xf infected. In riparian areas of northern California, the BGSS is able to transmit Xf from wild hosts to grapevine. PI Baumgartner's project showed that of riparian Xf hosts, only periwinkle (VINCA MAJOR) supports a high Xf titer. Results of PI Daane support the hypothesis that the cold tolerance of the almond strain of Xf allows it to survive better than the grape strain in almond. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
(A)GRAPEVINE RESISTANCE TO Xf: PI Gilchrist demonstrated that one of the anti-apoptotic genes discovered in their fumonisin B1 selection, when transgenically expressed in grapevine, reduced the Xf titer of inoculated vines to about 10^-5 of the control value and virtually eliminated symptom development. Grapevine lines with these characteristics show what may be practical field resistance to Xf. Results from introgression studies in PI Ramming's laboratory revealed no difference in fruit quality for susceptible versus resistant progeny, suggesting that cultivars showing resistance and suitable quality traits can be developed. The table grape breeding is carried out in parallel with similar CDFA-supported efforts on wine grape, with synergistic benefit. (B)REDUCING SHARPSHOOTER TRANSMISSION OF Xf: PI Falk achieved the first demonstration of double-stranded RNA-mediated RNA interference in a sharpshooter, raising the possibility of creating double-stranded RNA-expressing transgenic plants that will be lethal to sharpshooters feeding on them. PI Byrne's results from studies on neonicotinoid insecticides and parasitoids suggest that an integrated control strategy employing both kinds of GWSS control agents may be feasible. PI Almeida's Xf transmission observations define parameters for future model building. PI Triapitsyn's key and atlas of egg parasitoid species are fundamental to experiments aimed at biological management of GWSS. (C)Xf VIRULENCE: The mutational analyses performed by the Burr, Gabriel, Igo, and Hoch groups reveal functions of specific Xf genes, genes that may become targets for Xf control strategies. They also revealed that Xf has both offensive and defensive capabilities, against both substances produced by the plant host and competition from other microorganisms. That is, biofilm formation is an essential element of Xf virulence, so understanding biofilm formation similarly may reveal new approaches to interfering with Xf in plants. In the course of their investigations, the Hoch and Burr groups were able, for the first time, to culture Xf in grapevine xylem sap. This technical advance may allow more relevant in vitro experiments on Xf growth and behavior, including biofilm formation. (D)RESERVOIRS OF Xf: PI Almeida's and PI Sisterson's results show alfalfa to be a competent host for Xf, but the frequency of infected alfalfa plants appears to be too low for alfalfa to be a significant reservoir of Xf. PI Baumgartner's results suggest that, in riparian areas near vineyards, probably removal of periwinkle only will be sufficient to reduce transmission of Xf by BGSS to insignificant levels. Wholesale removal of riparian plants may not be necessary or helpful in PD mitigation.

Publications

  • de Leon, JH, GA Logarzo, SV Triapitsyn, and EG Virla. 2007. A new species of gonatocerus (Hymenoptera : mymaridae) from argentina, an egg parasitoid of tapajosa rubromarginata (Hemiptera : cicadellidae). Zootaxa 1619: 61-68.
  • de Leon, JH, GA Logarzo, SV Triapitsyn, and EG Virla. 2008. A new Gonatocerus (Hymenoptera: Mymaridae) from Argentina, with taxonomic notes and molecular data on the G-tuberculifemur species complex. Zootaxa 1949:1-29.
  • Shapland, EB, KM Daane, GY Yokota, C. Wistrom, JH Connell, RA Duncan, MA Viveros. 2006. Ground vegetation survey for Xylella fastidiosa in California almond orchard. Plant Disease 90: 905-909.


Progress 07/15/07 to 07/14/08

Outputs
OUTPUTS: A great variety of research types were supported in the past year, reflecting the areas that need to be explored to achieve mitigation of Pierce's disease (PD) They may be categorized as follows: (1) Developing Xf-resistant grapevine: The goals of achieving conventional and engineered resistance or tolerance of grapevine to Xf and grapevine resistance to the sharpshooter vector were pursued by several supported groups. Efforts on introgression into table grape of resistance from non-vinifera species, using molecular markers, were advanced in an effort that seeks to retain fruit quality and that is coordinated with similar CDFA-supported efforts on wine grape. A novel approach to engineered control of Xf infections is introduction of a transgene whose product can interfere with symptom development, particularly symptoms relying on programmed cell death in the grapevine. Relevant genes have been identified, and two have been able to provide substantial protection against symptom development in infected grapevines, producing Xf-infected grapevine that nevertheless survives and flourishes under greenhouse conditions. (2) Understanding Xf virulence: Survival of Xf in grapevine xylem depends of its ability to counteract plant defense mechanisms, to compete with other microorganisms that may be present, and to form biofilm-protected colonies of Xf bacteria. Supported research has identified several Xf genes that mediate efflux from the Xf cell of small molecules of types that may be produced by the plant and other microbes. Mutation of some of these genes greatly reduces the pathogenicity of Xf; others alter the behavior of Xf significantly, e.g., ability to aggregate or bind to surfaces, or the affinity with which the binding occurs. (3) Understanding the biology of Xf spread. Data were collected relating the number of GWSS insects on the host plant and the period of time on the plant to the efficiency of transmission, which was found to be affected significantly by the former but not by the latter. (4) Learning to exploit both chemical and biological approaches to control of the GWSS. Neonicotinoid insecticide effects on various life stages of the GWSS and specific parasitoids showed that insecticide doses that are effective against the GWSS nymph do not affect the embryo in the GWSS egg and allow survival of the egg parasitoid. (5) Identifying alternative Xf hosts and understanding their significance. Although alfalfa has potential as a reservoir and inoculum source for Xf transmission to grape, observed incidences of Xf in alfalfa appear to be too low for alfalfa to serve as a source. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The parts of this report on outcomes are keyed by number to the parts of output section. (1) Results from studies on introgression of resistance to Xf into table grape revealed no difference in advances of fruit quality for susceptible and resistant progeny, suggesting that cultivars showing resistance and suitable quality traits can be developed by the methods of conventional breeding. Supported efforts on transgene-mediated protection of grapevine are among several promising genetic engineering approaches now under study. (2) Genes found to be important to the survival and success of Xf in the host plant, including Xf's ability to protect itself against assault by substances produced by the plant or other microorganisms or to form a biofilm, are potential targets for anti-Xf strategies. (3) Understanding the variables of Xf transmission by the GWSS will underpin mathematical models of PD spread. (4) Results from studies on neonicotinoid insecticides and parasitoids suggest that an integrated control strategy employing both kinds of agents seems feasible.

Publications

  • Logarzo, G. A., J. H. de Leon, S. V. Triapitsyn, R. H. Gonzalez, and E. G. Virla. 2006. First report of a proconiine sharpshooter, Anacuerna centrolinea (Hemiptera: Cicadellidae), in Chile, with notes on its biology, host plants, and egg parasitoids. Annals of the Entomological Society of America 99 (5): 879-883.
  • Reddy, J. D, S. L. Reddy, D. L. Hopkins, and D. W. Gabriel. 2007. TolC is required for pathogenicity of Xylella fastidiosa in Vitis vinifera grapevines. Molec. Plant-Microbe Interact. 20 (4): 403-410.
  • Sisterson, M., R. Groves, K. Daane, and S. Thammiraju. 2007. Assessing the potential of forage alfalfa crops to serve as Xylella fastidiosa primary inoculum sources in the San Joaquin Valley. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 279-280.
  • Triapitsyn, S. V. 2006. Identify the species of Mymaridae reared in Argentina and Mexico for potential introduction to California against the glassy-winged sharpshooter and prepare and submit for publication a pictorial, annotated key to the ater-group species of Gonatocerus - egg parasitoids of the proconiine sharpshooters (Hemiptera: Cicadellidae: Proconiini) in the Neotropical region. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 111-113.
  • Triapitsyn, S. V. 2007. Identifying the species of Mymaridae reared in Argentina and Mexico for potential introduction to California against the glassy-winged sharpshooter and prepare and submitting for publication a pictorial, annotated key to the ater-group species of Gonatocerus - egg parasitoids of the proconiine sharpshooters (Hemiptera: Cicadellidae: Proconiini) in the Neotropical region. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 58-61.
  • Triapitsyn, S. V., and J. S. Bernal. 2008. Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera:Mymaridae). Journal of Insect Science, in press.
  • Triapitsyn, S. V., G. A. Logarzo, E. G. Virla, and J. H. de Leon. 2007. A new species of Gonatocerus (Hymenoptera: Mymaridae) from Argentina, an egg parasitoid of Tapajosa rubromarginata (Hemiptera: Cicadellidae). Zootaxa 1619: 61-68.
  • Virla, E. G., G. A. Logarzo, S. L. Paradell, and S. V. Triapitsyn. 2008. Bionomics of Oncometopia tucumana (Hemiptera: Cicadellidae), a sharpshooter from Argentina, with notes on its distribution, host plants, and egg parasitoids. Florida Entomologist 91(1): 55-62.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2006. Genetic studies of Gonatocerus metanotalis populations from Argentina uncover divergent clades: A prospective egg parasitoid candidate agent for the glassy-winged sharpshooter in California. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 52-55.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2006. ISSR-PCR DNA fingerprinting uncovers distinct banding patterns in Gonatocerus species 3 (G. sp. 3) individuals emerging from different host tribes: A prospective egg parasitoid candidate agent for the glassy-winged sharpshooter in California. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 48-51.
  • Almeida R. P. P., and M. P. Daugherty. 2007. Modeling sharpshooter transmission of Xylella fastidiosa. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 112-115.
  • Almeida R. P.P., and M. P. Daugherty. 2006. Modeling sharpshooter transmission of Xylella fastidiosa. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. p. 3.
  • Almeida, R. P. 2007. Role of alfalfa in the epidemiology of Xylella fastidiosa in California. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 231-234.
  • De La Fuente, L., E. Montane, Y. Meng, Y. Li, T. J. Burr, H.C. Hoch, and M. Wu. 2007. Assessing adhesion forces of type I and type IV pili of Xylella fastidiosa bacteria using a microfluidic flow chamber. Applied and Environmental Microbiology 73: 2690-2696.
  • De La Fuente, L., T. J. Burr, and H. C. Hoch. 2007. Mutations in type I and type IV pilus biosynthetic genes affect twitching motility rates in Xylella fastidiosa. Journal of Bacteriology 189: 7507-7510.
  • De La Fuente, L., T. J. Burr, H. C. Hoch. 2008. Autoaggregation of Xylella fastidiosa cells is influenced by type I and type IV pili. Applied and Environmental Microbiology 74: 5579-5582.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2006. Genetic characterization of Gonatocerus tuberculifemur from South America uncovers divergent clades: Prospective egg parasitoid candidate agent for the glassy-winged sharpshooter in California. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2006. Preliminary evidence from reproductive compatibility studies suggests that Gonatocerus tuberculifemur exists as a cryptic species complex, or a new species is identified: Development and utility of molecular diagnostic markers. In: Proceedings of the 2006 Pierce's Disease Research Symposium, November 27-29, 2006, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 44-47.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2007. Progress on resolving the Gonatocerus tuberculifemur complex: Neither COI nor ITS2 sequence data alone can discriminate all the species within the complex, whereas, ISSR-PCR DNA fingerprinting can. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 73-76.
  • de Leon, J. H., G. A. Logarzo, and S. V. Triapitsyn. 2008. Molecular characterization of Gonatocerus tuberculifemur (Ogloblin) (Hymenoptera: Mymaridae), a prospective Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) biological control candidate from South America: Divergent clades. Bulletin of Entomological Research 98: 97-108.
  • Falk, B. W., M. R. Sudarshana, and M. Parrella. 2007. RNA interference and control of the glassy-winged sharpshooter and other leafhopper vectors of Pierce's Disease. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 86 - 89.
  • Galvani, C. D. , Y. Li, T. J. Burr, and H. C. Hoch. 2007. Twitching motility among pathogenic Xylella fastidiosa isolates and the influence of bovine serum albumin on twitching-dependent colony fringe morphology. FEMS Microbiol. Lett. 268: 202-208.
  • Gilchrist, D., and J. Lincoln. 2007. Evaluation of genes isolated by a functional genetic screen for suppression of bacterial growth or symptoms in Pierce's disease. In: Proceedings of the 2007 Pierce's Disease Research Symposium, December 12-14, 2007, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA. pp. 18-21.
  • Harvey, J. J. W., J. E. Lincoln, and D. G. Gilchrist. 2008. Programmed cell death suppression in transformed plant tissue by tomato cDNAs identified from an Agrobacterium rhizogenes-based functional screen. Molecular Genetics and Genomics 279:509-521.
  • Li, Yaxin, G. Hao, C. D. Galvani, Y. Meng, L. De La Fuente, H. C. Hoch, and T. J. Burr. 2007. Type I and type IV pili of Xylella fastidiosa affect twitching motility, biofilm formation, and cell-cell aggregation. Microbiology 153: 719-726.


Progress 07/15/06 to 07/14/07

Outputs
OUTPUTS: This grant, administered through the University of California Division of Agriculture and Natural Resources, sponsored the UC Pierce's Disease Research Grants Program (2006-09), a continuation of the 2001 research grants program. The program funds work that addressed Pierce's disease and its vectors. During the peer-review process conducted in 2006 and again in 2007, 16 projects were selected for funding. The following are grants funded for 2006-08. Identify the species of Mymaridae reared in Argentina and Mexico for potential introduction to California against GWSS and prepare and submit for publication a pictorial, annotated key to the ater-group species of GONATOCERUS - Egg parasitoids of the Proconii; ++XYLELLA FASTIDIOSA group, cultivar, climate on ALS; ++Host plant preference and natural infectivity of insect vectors on common weeds known to host XYLELLA FASTIDIOSA; ++Understanding control of XYLELLA FASTIDIOSA cell aggregation: Importance in colonization and biofilm development in grapevine and sharpshooter foregut; ++Modeling sharpshooter transmission of XYLELLA FASTIDIOSA; ++Role of alfalfa in the epidemiology of XYLELLA FASTIDIOSA in California; ++Breeding PD-resistant table and raisin grapes and the development of markers for additional sources of resistance; ++The spatial distribution of PD across the North Coast: Patterns, causes, and implications for management; ++Assessing the potential of forage alfalfa crops to serve as XYLELLA FASTIDIOSA, primary inoculum sources in the San Joaquin Valley; ++Use of peptide aptamers to explore blocking of Type I secretion of XYLELLA FASTIDIOSA; ++Resistance to PD by transgenic expression of plant-derived anti-apoptotic genes; ++The role of GWSS salivary enzymes in infection and movement of XYLELLA FASTIDIOSA; ++Evaluation of the impact of neonicotinoid insecticides on the glassy-winged sharpshooter, HOMALODISCA VITRIPENNIS, and its egg parasitoids; ++The role of type V secretion autotransporters in the virulence of XYLELLA FASTIDIOSA; ++The significance of XYLELLA FASTIDIOSA type I and type IV pili in both biofilm structure, bacterial survival in biofilms, and in DNA secretion and uptake; ++RNA-interference and control of the glassy-winged sharpshooter, HOMALODISCA COAGULATA, and other leafhopper vectors of Pierce's disease. Projects were presented at a research symposium organized annually by the California Department of Food and Agriculture Pierce's Disease Control Program, and the proceedings are available at http://www.cdfa.ca.gov/pdcp/Research_Symposium_Index.html. PARTICIPANTS: Individuals: Project Director George E. Bruening directed the UC Pierce's Disease Research Grants Program in 2006-07. Project investigators or co-PIs of individual research projects funded through this grant are R. P. Almeida, E. A. Backus, K. Baumgartner, F. Byrne, T. J. Burr, K. M. Daane, B. Falk, D. W. Gabriel, D. G. Gilchrist, R. L. Groves, H. C. Hoch, M. Igo, B. Kirkpatrick, J. M. Labavitch, J. E. Lincoln, S. Lindow, A. Matsumoto, M. Parrella, J. F. Quinn, D. W. Ramming, M. S. Sisteron, M. Sudarshan, S. Triapitsyn, M. A. Walker. Support for financial and administration of the grants program: M. C. Caruso. Partner organizations are ESPM Insect Biology University of California, Berkeley; USDA-ARS; Plant Pathology Cornell University; Plant Pathology University of Florida; Plant Pathology University of California, Davis; Plant Sciences University of California Davis; Environmental Science & Policy University of California, Davis; Microbiology, University of California, Davis; Entomology University of California, Riverside; Viticulture & Enology University of California, Davis; California Department of Food and Agriculture. TARGET AUDIENCES: Grape growers, the grape agricultural industry in general, and the wine industry are the ultimate direct audiences for the research products. The information developed by supported projects also is intended to help the California Department of Food and Agriculture in its Pierce's disease control programs. Research reports are given at an annual Pierce's disease research symposium and published in a proceedings volume and in regular publications of the investigators, advancing not only the study of Pierce's disease but also of grapevine biology and other grapevine diseases. Whatever saving of grape production is accomplished presumably will benefit consumers as well as producers.

Impacts
Research supported by this grant will develop systems that allow XYLELLA FASTIDIOSA, an organism whose fundamental characteristics previously had received little attention, to be studied by the tools of modern molecular biology.

Publications

  • Esser, T., ed. 2006. Proceedings, 2006 Pierce's Disease Research Symposium, San Diego, CA. California Department of Food and Agriculture, Sacramento, CA.