Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 111 - Conservation and Efficient Use of Water | 210 - Water resources | 1010 - Nutrition and metabolism | 10% |
| 204 - Plant Product Quality and Utility (Preharvest) | 1099 - Tropical/subtropical fruit, general/other | 1060 - Biology (whole systems) | 10% |
| 206 - Basic Plant Biology | 1099 - Tropical/subtropical fruit, general/other | 1060 - Biology (whole systems) | 10% |
| 212 - Pathogens and Nematodes Affecting Plants | 1099 - Tropical/subtropical fruit, general/other | 1160 - Pathology | 10% |
| 212 - Pathogens and Nematodes Affecting Plants | 1139 - Grapes, general/other | 1160 - Pathology | 10% |
| 212 - Pathogens and Nematodes Affecting Plants | 1212 - Almond | 1160 - Pathology | 10% |
| 212 - Pathogens and Nematodes Affecting Plants | 1219 - Edible tree nuts, general/other | 1160 - Pathology | 10% |
| 212 - Pathogens and Nematodes Affecting Plants | 999 - Citrus, general/other | 1160 - Pathology | 10% |
| 215 - Biological Control of Pests Affecting Plants | 1139 - Grapes, general/other | 1160 - Pathology | 10% |
| 215 - Biological Control of Pests Affecting Plants | 1139 - Grapes, general/other | 1180 - Pharmacology | 10% |
This research proposal is aimed at developing and implementing new practices for the management of diseases in grape, almond and pistachio in California. The first research topic addresses Pierces Disease of grapevine caused by the bacteria Xylella fastidiosa (Xf). Xf remains one of the major threats to grape production in California because affected vines can die rapidly. Also, the introduction to southern California of a more effective insect vector has increased the risks of a disease outbreak. One goal for this research is to identify the organisms living inside grapevines so we can select potential natural enemies of the bacteria. The microorganisms are identified with culture-dependent and culture-independent analyses of grapevine tissue samples. The beneficial fungi able to inhibit the bacteria in laboratory tests will also be evaluated for their ability to mitigate the disease development in a greenhouse assay after being re-introduced into grapevines. Second, we will characterize if the molecules produced by these beneficial fungi can be used as a curative treatment for the disease. The other topic of research focuses on fungal wood diseases in grape, almond, and pistachio. These diseases decrease yield and longevity of affected vineyards and orchards. Woody crops are all affected with these diseases although some fruit and nut varieties are more tolerant than others. Fungi infect through pruning wounds and because pruning is a necessary practice in fruit and nut productions, wood diseases are a chronic problem. There are no current eradicative controls in any of these crops, and thus prevention is essential, which is attempted primarily through conventional fungicide applications on pruning wounds. Accordingly, this first goal is to identify anatomical and chemical markers of resistance in plant cell wall of grape, almond and pistachio varieties using tissue microscopy and Nuclear magnetic resonance spectroscopy. This would allow to quickly evaluating the level of resistance of commercial varieties and to identify new source of resistance in the USDA-National Clonal Germplasm Repositories for future breeding programs. The second goal is to address the missing gap for the control of wood diseases in organic wine grape productions. Indeed, only conventional products are currently registered in California. Thus the goal is to obtain field data on the efficacy of an organic product made with boron and zinc with the goal to register this product. This project will also evaluate the costs of wood diseases in table grape production using an online survey that will be sent out to grape growers. Finally, the last objective is aimed at improving crop productivity in the limited natural resources environment that California is facing (water quantity and quality, land availability) by implementing high density planting. This practice will provide a sustainable economic strategy that will counterbalance the economic losses in citrus and avocado productions after citrus greening and the polyphagous shot hole borer become established.
One goal for his project is to identify, within the pool of microbial communities inhabiting grapevines, potential natural enemies of Xylella fastidiosa (Xf) the causal agent of Pierces Disease (PD). We collected tissues (shoots, sap, petioles) from both PD-infected and PD-escaped vines in California vineyards. The culturable fungi leaving in these tissues were identified with ribosomal DNA sequences and compared to sequences of specimen posted in the GenBank database. We screened these fungi against Xf in a lab bioassay and showed that seven were able to inhibit the bacterium. We are currently assessing their ability to mitigate PD development in planta. We are also in the process of characterizing the chemical structure and the anti-Xf natural compounds produced by these fungi and their potential use as a curative treatment in greenhouses assays. In addition, this research will provide a culture-independent analysis of the microbial population using high throughput sequencing. Understanding the shift in microbial communities inhabiting healthy and escaped grapevine will provide insights on the disease etiology and will facilitate the identification of biocontrol agents. The other goal of this research is to improve the management against wood diseases in fruit and nut crops. First, we want to identify the source of resistance in almond, pistachio, and grape varieties. We will look at wood anatomy and chemistry in response to fungal infection. Wood anatomy will be assessed using light and scanning electron microscopy images to measure anatomical parameters such as the size/number of the xylem vessels, thickness of the cell walls. Wood chemistry will be assessed by NMR spectroscopy to measure hemicellulose and lignin composition such as syringyl to guaicyl ratios and linkages. Second, we want to evaluate in commercial vineyard the efficacy of an organic product developed at UCR against wood diseases. The product will be applied on pruning wounds and challenged with artificial inoculation of fungal spores. The product efficacy will be reported as a measure of the number of pruning wounds infected with the fungi tested over the total number inoculated. The data will be analyzed using a weighted least square ANOVA to determine if there were significant differences among least square means. Finally we will evaluate the costs of wood diseases to table grape production. The questionnaire of the online survey was formulated with input from UC viticulture Farm Advisors, pathologists, and economists and was sent electronically to table grape growers. Answers will be collected over 3 years, after which data will be summarized and analyzed. Finally, we will evaluate the benefits of high density planting in avocado and citrus with regards to yield and fruit quality. We will plant twice as many trees (about 400 trees per acre) as with the California standards for both citrus and avocado. We will evaluate over the years, yield, fruit size and quality, plant water needs.
Target Audience
This project targets several industry groups including wine grape, table grape, raisin, grape juice, citrus, almond, mangoand avocado. The information collected is extended to a range of stakeholders, including growers, extension agents, state and federal agencies, scientists and the general public.
Changes / Problems
Nothing Reported
Training & Professional Development
Nothing Reported
Dissemination Streams
I have developed a strong statewide extension program working in close collaboration with farm advisors. In alignment with the mission of the Agricultural Experiment Station (AES), I support the AES continuum of translating University driven research to California growers. I communicate my research findings with various stakeholder groups through industry meetings, online (lab webpage, videos), newsletters and workshops.
Next Reporting Steps
Nothing Reported