Renaud Travadon & Kendra Baumgartner
We developed methodologies to rapidly and reliably screen grapevines in the greenhouse. Now we are examining cultivars and germplasm for sources of resistance to trunk diseases, specifically Eutypa dieback and Phomopsis dieback.
Link to presentation: Evaluating grapevine germplasm for resistance to Eutypa Dieback.
Mizuho Nita, and Sabrina Hartley
Progress update on development of web and mobile diagnostic application that will enable growers to properly diagnose trunk vine diseases and in return help determine proper management practices for the specific trunk disease identified.
Link to the presentation: Development of web application of grapevine trunk diagnostic tool
Renaud Travadon & Kendra Baumgartner
Developing rapid grapevine screening process to identify wine and table grape cultivars for resistance to Eutypa Dieback based on foliar and woody symptoms. Future efforts towards comparing gene expression profile between previously characterized resistance and susceptible cultivars.
Based on previously discovered Phomopsis resistant genes, determine if woody tissue resistant genes can be linked to green tissue symptom expression.
Determine how anatomical and chemical differences effect Botryosphaeria resistance levels in 7 table grape cultivars.
Link to the presentation: “Baumgartner and Travadon presentation for the board meeting 2014”
Results and Outputs – Utilize qPCR to detect differential expression of target genes 
Significant Outcomes & Impacts – Identification of which pathogens are present in nursery stock grapevine wood. Eliminate contaminated stocks that would otherwise be used for propagation.
Goal – Identify new anatomical and biochemical markers of resistance in grapevine wood.
Activities – Characterize changes in the wood that correspond to resistance to Eutypa dieback, using cultivars with known resistance/tolerance: Merlot (resistant), Cabernet Sauvignon (intermediate), and Thompson seedless (susceptible).
Results & Outputs – Identified differences in cell wall and xylem characteristics. Susceptible tablegrape Thompson seedless had low lignin and high glucan in its cell walls, whereas resistant winegrape Merlot had high lignin and low glucan (Cabernet Sauvignon was intermediate). Xylem vessel diameter also differed between these two cultivars; Thompson seedless had the largest vessels and Merlot had the smallest.
Significant Outcomes & Impacts – These markers of Eutypa resistance will compliment the detached-cane screening method, to provide additional measures of resistance. This is important because we are evaluating genetically-diverse germplasm, which may exhibit different modes of resistance. These markers are now being evaluated for the other trunk diseases (Botryosphaeria dieback, Esca, Phomopsis dieback), along with the detached-cane method of screening.
Goal 2 – Accurate identification of trunk fungi
Activities – Allow for proper disease management and control practices
Results & Outputs – Developed a comprehensive DNA sequence database of trunk inhabiting fungi
Significant Outcomes & Impacts – Accurate species identification will lead to proper disease management practices.
Goal – Develop a rapid and reliable screening technique for resistant grape germplasm.
Activities – Compared screening methods for resistance to Eutypa dieback among nine genetically-diverse cultivars.
Results & Outputs
Merlot and Primitivo were most resistant to Eutypa dieback, based on both methods (hardwood cuttings and detached canes). However, the detached-cane method – a rapid alternative that takes only 5 weeks – differentiated cultivars similarly to the hardwood-cutting method, which is the standard in most labs.
The susceptible control, table-grape cultivar Thompson seedless, was ‘beat’ by an even more susceptible table grape cultivar, Husseine. Fortunately, this is not a commercial table grape, but it can serve as a new susceptible control in our studies.
Significant Outcomes & Impacts
The detached-cane method will serve as a phenotyping assay for use with materials from VitisGen and other grape breeding projects. In this way, our SCRI project builds on other SCRI projects that have already completed major genotyping efforts.
Goal – Develop visual diagnostic aids for trunk diseases.
Activities—Create a web/mobile application and website for trunk disease diagnosis.
Results & Outputs
Developed beta-versions of logic and flow charts.
Significant Outcomes & Impacts
Accurate disease diagnosis will minimize losses by leading growers to proper management practices.
Link: Trunk Disease Management for Eastern grape growing regions
Goal 1 – Develop a detection tool for spores of wood-canker pathogens (aka trunk pathogens), combined with new molecular markers for rapid identification.
Activities – Evaluated spore traps in young, apparently-healthy vineyards vs. mature, diseased vineyards.
Results & Outputs – Demonstrated that both young and mature vineyards are at similar risk of infection by spores of the same trunk pathogens.
Significant Outcomes & Impacts – Growers routinely forego preventative practices in young vineyards because trunk diseases are not a serious problem until year 8. Our results make it clear – disease prevention should be adopted in young vineyards.
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