Our goal is to develop a new method to detect trunk diseases by sampling asymptomatic leaves. We revealed a unique set of grape genes expressed in asymptomatic leaves in the early phase of infection, using Botryosphaeria dieback pathogen Neofusicoccum parvum as a model to study host responses to a trunk pathogen. Tests are in progress to confirm specificity of these grape genes to Neofusicoccum infection, in inoculations with other trunk pathogens, common foliar pathogens, and to rule out possible interactions with drought stress.
Link to presentation:Early Detection
We as researchers think the preventative practices for trunk diseases are effective. We surveyed growers to see if they feel the same.
Link to presentation:Trunk Disease Management, grower usage and perspective of preventative practices.
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.
Vicken Hillis, Mark Lubell, and Kendra Baumgartner
This research is a broad effort to understand grower decision making in the context of trunk disease management.” A presentation on a research survey to identify hurdles in which farm managers, consultants, and the like, face when adoption of new management practices may be necessary.
Link to the presentation: “Identifying Sociological Hurdles to Adoption of Trunk Disease Management Practices“
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”
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 a detection tool for the early stage of infection, to quickly identify infected nursery stock, and as a study tool for field-testing new pruning-wound protectants.
Activities – Defined the timing and characteristics of the early stage of infection by the Botryosphaeria dieback pathogen Neofusicoccum parvum, based on spread of the infection and anatomic changes in the trunk, and differential gene expression in the leaves.
Use of High Resolution Computed Tomography
HRCT of grapevine at 2weeks after infection
HRCT of uninfected grapevine
Our focus in 2013-2014 was on Neofusicoccum parvum, which attacks grape, almond,
and pistachio. As the canker developed, anatomical responses in the woody stems of
potted grapes were examined by light microscopy and High Resolution Computed
Tomography (HRCT). Comparisons of inoculated – wounded plants (IW) vs. non-
inoculated – wounded plants (NIW) showed the main differences at 2 MPI. IW plants
were characterized by xylem vessels filled with gels, in stems of intact plants examined
For more movies, please click the link below:
Results & Outputs – Identified a set of eight grapevine genes (aka ‘molecular signature’) expressed in leaves during the early stage of infection from 0.5 to 1.5 months post-inoculation (MPI). For e.g., genes VIT_00s1455g00010 (dark bars) and VIT_01s0026g02710 (white bars) are highly expressed in inoculated plants, compared to the non-inoculated control plants.
Significant Outcomes & Impacts – Demonstrated ‘Proof of concept’, that the early stage of infection in the stem is detectable in asymptomatic leaves. This was first in a series of experiments, the next of which will confirm specificity of the molecular signature for possible interactive effects with drought stress and other trunk pathogens.